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Sample records for hafnium correlations entre

  1. Correlations between nuclear data and integral slab experiments: the case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J M

    1999-07-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  2. Correlations between nuclear data and integral slab experiments: the case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J.M

    1999-07-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  3. Correlations between nuclear data and results of integral slab experiments. Case of hafnium; Correlations entre donnees nucleaires et experiences integrales a plaques: le cas du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Palau, J M

    1997-10-22

    The aim of this thesis was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular `mock-up` reactor. In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods (APOLLO2 code) together with Monte Carlo- type simulations (TRIPOLI4 code) enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope {sup 177}Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent`s efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author) 128 refs.

  4. Commercial production of metal hafnium and hafnium-based products

    International Nuclear Information System (INIS)

    Negodin, D.A.; Shtutsa, M.G.; Akhtonov, S.G.; Il'enko, E.V.; Kobyzev, A.M.

    2012-01-01

    Hafnium possesses a unique complex of physical and chemical properties which allow the application of products on its basis in various industries. Joint Stock Company 'Chepetsky Mechanical Plant' is the single enterprise which produces hafnium on the territory of Russia. The manufacture of metal hafnium with the total content of zirconium and hafnium, at least, 99,8 % of weights is developed at the present time at Joint Stock Company CHMZ. The weight of melted hafnium ingots is up to 1 ton. Manufacture of wide range of products from hafnium is implemented. The plates from a hafnium with thickness of 0.60 mm which are used for emergency control cartridges of VVER-440 reactors are the most critical product. It is shown that ingots and products obtained from metal hafnium correspond to the Russian and international standards for reactor materials in chemical composition, mechanical and corrosion properties.

  5. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    Energy Technology Data Exchange (ETDEWEB)

    Chain, Cecilia Y. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Rivas, Patricia [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Universidad Nacional de La Plata (Argentina). Facultad de Ciencias Agrarias y Forestales; Pasquevich, Alberto F. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica; Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), La Plata (Argentina). IFLP-CCT; Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)

    2014-07-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H{sub 2}O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω{sub Q} = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H{sub 2}O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω{sub Q} = 168 Mrad/s. (orig.)

  6. Thermal behaviour of hafnium diethylenetriaminepentaacetate studied using the perturbed angular correlation technique

    International Nuclear Information System (INIS)

    Chain, Cecilia Y.; Rivas, Patricia

    2014-01-01

    Polyaminecarboxilic ligands like diethylenetriaminepentaacetic acid form stable complexes with many heavy metal ions, excelling as cation chelants especially in the field of radiopharmacy. The aim of this work is to characterize, by using the Time Differential Perturbed Angular Correlations (TDPAC) technique, the hyperfine interactions at hafnium sites in hafnium diethylenetriaminepentaacetate and to investigate their evolution as temperature increases. TDPAC results for KHfDTPA.3H 2 O obtained by chemical synthesis yield a well defined and highly asymmetric interaction of quadrupole frequency ω Q = 141 Mrad/s, which is consistent with the existence of a unique site for the metal in the crystal lattice. The thermal behaviour of the chelate is investigated by means of differential scanning calorimetry and thermogravimetrical analyses revealing that an endothermic dehydration of KHfDTPA.3H 2 O takes place in one step between 80 C and 180 C. The anhydrous KHfDTPA thus arising is characterized by a fully asymmetric and well defined interaction of quadrupole frequency ω Q = 168 Mrad/s. (orig.)

  7. Metallurgy of zirconium and hafnium

    International Nuclear Information System (INIS)

    Baryshnikov, N.V.; Geger, V.Eh.; Denisova, N.D.; Kazajn, A.A.; Kozhemyakin, V.A.; Nekhamkin, L.G.; Rodyakin, V.V.; Tsylov, Yu.A.

    1979-01-01

    Considered are those properties of zirconium and of hafnium, which are of practical interest for the manufacture of these elements. Systematized are the theoretical and the practical data on the procedures for thermal decomposition of zirconia and for obtaining zirconium dioxide and hafnium dioxide by a thermal decomposition of compounds and on the hydrometallurgical methods for extracting zirconium and hafnium. Zirconium and hafnium fluorides and chlorides production procedures are described. Considered are the iodide and the electrolytic methods of refining zirconium and hafnium

  8. Gravimetric determination of hafnium through its arsenate in carbide and boride of hafnium

    International Nuclear Information System (INIS)

    Rasulbekova, R.A.; Mamedov, I.A.

    1976-01-01

    A gravimetric method of determining hafnium through hydroarsenate has been recommended. The method differs from the known ones by its simplicity and by the recalculation coefficient which is more than by 50% smaller than that used in preparing a weight form of HfO 2 . Upon development of gravimetric determination of hafnium through hydro-and pyroarsenate, an investigation has been conducted with the aim to find some physico-chemical constants of hafnium hydroarsenate. The weighed amount of hafnium hydroarsenate is dissolved in sulphuric acid (2:5). The precipitate of hafnium hydroarsenate has been studied for recording infrared absorption spectra. Thermographic analysis of the precipitate has been performed. Thermogram reveals endothermal effect at 105 deg C and exothermal at 840 deg C. Water solubility of hafnium has been determined equal to 1.75x10 6 g mol/l. The corresponding solubility product of the precipitate has been calculated which is 2.1x10 -17 . It is shown that the method possesses certain selectivity, sufficient accuracy, and is rather fast. It has been established that determination can be performed in the presence of excess amounts of ions

  9. Correlations between nuclear data and integral slab experiments: the case of hafnium

    International Nuclear Information System (INIS)

    Palau, J.M.

    1999-01-01

    The aim of this work was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor.In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods together with Monte Carlo- type simulations enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope 177 Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  10. The corrosion behavior of hafnium in high-temperature-water environments

    Energy Technology Data Exchange (ETDEWEB)

    Rishel, D.M.; Smee, J.D.; Kammenzind, B.F.

    1999-10-01

    The high-temperature-water corrosion performance of hafnium is evaluated. Corrosion kinetic data are used to develop correlations that are a function of time and temperature. The evaluation is based on corrosion tests conducted in out-of-pile autoclaves and in out-of-flux locations of the Advanced Test Reactor (ATR) at temperatures ranging from 288 to 360 C. Similar to the corrosion behavior of unalloyed zirconium, the high-temperature-water corrosion response of hafnium exhibits three corrosion regimes: pretransition, posttransition, and spalling. In the pretransition regime, cubic corrosion kinetics are exhibited, whereas in the posttransition regime, linear corrosion kinetics are exhibited. Because of the scatter in the spalling regime data, it is not reasonable to use a best fit of the data to describe spalling regime corrosion. Data also show that neutron irradiation does not alter the corrosion performance of hafnium. Finally, the data illustrate that the corrosion rate of hafnium is significantly less than that of Zircaloy-2 and Zircaloy-4.

  11. Correlations between nuclear data and results of integral slab experiments. Case of hafnium

    International Nuclear Information System (INIS)

    Palau, J.M.

    1997-01-01

    The aim of this thesis was to evaluate how much integral slab experiments can both reduce discrepancies between experimental results and calculations, and improve the knowledge of hafnium isotopes neutronic parameters by an adapted sensitivity and uncertainty method. A statistical approach, based on the generalized least squares method and perturbation theory, has been incorporated into our calculation system in order to deduce microscopic cross-section adjustments from observed integral measurements on this particular 'mock-up' reactor. In this study it has been established that the correlations between integral parameters and hafnium capture cross-sections enable specific variations in the region of resolved resonances at the level of multigroup and punctual cross-sections recommended data (JEF-2.2 evaluation) to be highlighted. The use of determinist methods (APOLLO2 code) together with Monte Carlo- type simulations (TRIPOLI4 code) enabled a depth analysis of the modelling approximations to be carried out. Furthermore, the sensitivity coefficient validation technique employed leads to a reliable assessment of the quality of the new basic nuclear data. In this instance, the adjustments proposed for certain isotope 177 Hf resonance parameters reduce, after error propagation, by 3 to 5 per cent the difference between experimental results and calculations related to this absorbent's efficiency. Beyond this particular application, the qualification methodology integrated in our calculation system should enable other basic sizing parameters to be treated (chemical / geometric data or other unexplored nuclear data) to make technological requirements less stringent. (author)

  12. Hafnium isotope stratigraphy of ferromanganese crusts

    Science.gov (United States)

    Lee; Halliday; Hein; Burton; Christensen; Gunther

    1999-08-13

    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in (87)Sr/(86)Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  13. SEPARATION OF HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Overholser, L.B.; Barton, C.J. Sr.; Ramsey, J.W.

    1960-05-31

    The separation of hafnium impurities from zirconium can be accomplished by means of organic solvent extraction. The hafnium-containing zirconium feed material is dissolved in an aqueous chloride solution and the resulting solution is contacted with an organic hexone phase, with at least one of the phases containing thiocyanate. The hafnium is extracted into the organic phase while zirconium remains in the aqueous phase. Further recovery of zirconium is effected by stripping the onganic phase with a hydrochloric acid solution and commingling the resulting strip solution with the aqueous feed solution. Hexone is recovered and recycled by means of scrubbing the onganic phase with a sulfuric acid solution to remove the hafnium, and thiocyanate is recovered and recycled by means of neutralizing the effluent streams to obtain ammonium thiocyanate.

  14. Zirconium and hafnium

    Science.gov (United States)

    Jones, James V.; Piatak, Nadine M.; Bedinger, George M.; Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    Zirconium and hafnium are corrosion-resistant metals that are widely used in the chemical and nuclear industries. Most zirconium is consumed in the form of the main ore mineral zircon (ZrSiO4, or as zirconium oxide or other zirconium chemicals. Zirconium and hafnium are both refractory lithophile elements that have nearly identical charge, ionic radii, and ionic potentials. As a result, their geochemical behavior is generally similar. Both elements are classified as incompatible because they have physical and crystallochemical properties that exclude them from the crystal lattices of most rock-forming minerals. Zircon and another, less common, ore mineral, baddeleyite (ZrO2), form primarily as accessory minerals in igneous rocks. The presence and abundance of these ore minerals in igneous rocks are largely controlled by the element concentrations in the magma source and by the processes of melt generation and evolution. The world’s largest primary deposits of zirconium and hafnium are associated with alkaline igneous rocks, and, in one locality on the Kola Peninsula of Murmanskaya Oblast, Russia, baddeleyite is recovered as a byproduct of apatite and magnetite mining. Otherwise, there are few primary igneous deposits of zirconium- and hafnium-bearing minerals with economic value at present. The main ore deposits worldwide are heavy-mineral sands produced by the weathering and erosion of preexisting rocks and the concentration of zircon and other economically important heavy minerals, such as ilmenite and rutile (for titanium), chromite (for chromium), and monazite (for rare-earth elements) in sedimentary systems, particularly in coastal environments. In coastal deposits, heavy-mineral enrichment occurs where sediment is repeatedly reworked by wind, waves, currents, and tidal processes. The resulting heavy-mineral-sand deposits, called placers or paleoplacers, preferentially form at relatively low latitudes on passive continental margins and supply 100 percent of

  15. Molten salt scrubbing of zirconium or hafnium tetrachloride

    International Nuclear Information System (INIS)

    Lee, E.D.; McLaughlin, D.F.

    1990-01-01

    This patent describes a continuous process for removing impurities of iron or aluminum chloride or both from vaporous zirconium or hafnium chloride or both. It comprises: introducing impure zirconium or hafnium chloride vapor or both into a middle portion of an absorbing column containing a molten salt phase, the molten salt phase absorbing the impurities of iron or aluminum chloride or both to produce chloride vapor stripped of zirconium or hafnium chloride; introducing sodium or potassium chloride or both into a top portion of the column; controlling the top portion of the column to between 300--375 degrees C.; heating a bottom portion of the column to 450--550 degrees C. To vaporize zirconium chloride or hafnium chloride or hafnium and zirconium chloride from the molten salt; withdrawing molten salt substantially free of zirconium and hafnium chloride from the bottom portion of the column; and withdrawing zirconium chloride or hafnium chloride or hafnium and zirconium chloride vapor substantially free of impurities of iron and aluminum chloride from the top of the column

  16. Recovery of hafnium values from loaded extraction solvent

    International Nuclear Information System (INIS)

    Abodishish, H.A.

    1989-01-01

    This patent describes an improvement in a process for recovering high purity hafnium hydroxide from a methyl isobutyl ketone organic solvent that is substantially free of sulfate ions and contains hafnium thiocyanate and thiocyanic acid. The improvement comprising reacting the organic solvent with ammonia to produce a reaction product in the form of a methyl isobutyl ketone organic solvent that is substantially free of sulfate ions and contains ammonium thiocyanite solution and hafnium hydroxide; separating the constituents of the reaction product in accordance with their respective specific gravities to produce a hafnium hydroxide sludge as one of the separation products; and removing the liquid component of the sludge to yield a high purity hafnium hydroxide ready for calcination to hafnium oxide

  17. Hafnium carbide formation in oxygen deficient hafnium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rodenbücher, C. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); Hildebrandt, E.; Sharath, S. U.; Kurian, J.; Komissinskiy, P.; Alff, L. [Technische Universität Darmstadt, Institute of Materials Science, 64287 Darmstadt (Germany); Szot, K. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); University of Silesia, A. Chełkowski Institute of Physics, 40-007 Katowice (Poland); Breuer, U. [Forschungszentrum Jülich GmbH, Central Institute for Engineering, Electronics and Analytics (ZEA-3), 52425 Jülich (Germany); Waser, R. [Forschungszentrum Jülich GmbH, Peter Grünberg Institute (PGI-7), JARA-FIT, 52425 Jülich (Germany); RWTH Aachen, Institute of Electronic Materials (IWE 2), 52056 Aachen (Germany)

    2016-06-20

    On highly oxygen deficient thin films of hafnium oxide (hafnia, HfO{sub 2−x}) contaminated with adsorbates of carbon oxides, the formation of hafnium carbide (HfC{sub x}) at the surface during vacuum annealing at temperatures as low as 600 °C is reported. Using X-ray photoelectron spectroscopy the evolution of the HfC{sub x} surface layer related to a transformation from insulating into metallic state is monitored in situ. In contrast, for fully stoichiometric HfO{sub 2} thin films prepared and measured under identical conditions, the formation of HfC{sub x} was not detectable suggesting that the enhanced adsorption of carbon oxides on oxygen deficient films provides a carbon source for the carbide formation. This shows that a high concentration of oxygen vacancies in carbon contaminated hafnia lowers considerably the formation energy of hafnium carbide. Thus, the presence of a sufficient amount of residual carbon in resistive random access memory devices might lead to a similar carbide formation within the conducting filaments due to Joule heating.

  18. SEPARATING HAFNIUM FROM ZIRCONIUM

    Science.gov (United States)

    Lister, B.A.J.; Duncan, J.F.

    1956-08-21

    A dilute aqueous solution of zirconyl chloride which is 1N to 2N in HCl is passed through a column of a cation exchange resin in acid form thereby absorbing both zirconium and associated hafnium impurity in the mesin. The cation exchange material with the absorbate is then eluted with aqueous sulfuric acid of a O.8N to 1.2N strength. The first portion of the eluate contains the zirconium substantially free of hafnium.

  19. Determination of hafnium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Yoshida, Isao; Kobayashi, Hiroshi; Ueno, Keihei.

    1977-01-01

    Optimum conditions for atomic absorption spectrophotometric determination of hafnium were investigated by use of a Jarrel-Ash AA-1 instrument which was equipped with a premixed gas burner slotted 50 mm in length and 0.4 mm in width. Absorption of hafnium, which was atomized in an nitrous oxide-acetylene flame, was measured on a resonance line at 307.29 nm. The absorption due to hafnium was enhanced in the presence of ammonium fluoride and iron(III) ion, as shown in Figs. 2 and 3, depending on their concentration. The highest absorption was attained by the addition of (0.15 -- 0.3)M ammonium fluoride, 0.07 M of iron(III) ion and 0.05 M of hydrochloric acid. An excess of the additives decreased the absorption. The presence of zirconium, which caused a significant interference in the ordinary analytical methods, did not affect the absorption due to hafnium, if the zirconium concentration is less than 0.2 M. A standard procedure was proposed; A sample containing a few mg of hafnium was dissolved in a 25-ml volumetric flask, and ammonium fluoride, ferric nitrate and hydrochloric acid were added so that the final concentrations were 0.3, 0.07 and 0.05 M, respectively. Atomic absorption was measured on the aqueous solution in a nitrous oxide-acetylene flame and the hafnium content was calculated from the absorbance. Sensitivity was as high as 12.5 μg of Hf/ml/l% absorption. The present method is especially recommendable to the direct determination of hafnium in samples containing zirconium. (auth.)

  20. New solvent extraction process for zirconium and hafnium

    International Nuclear Information System (INIS)

    Takahashi, M.; Katoh, Y.; Miyazaki, H.

    1984-01-01

    The authors' company developed a new solvent extraction process for zirconium and hafnium separation, and started production of zirconium sponge by this new process in September 1979. The process utilizes selective extraction of zirconium oxysulfate using high-molecular alkyl amine, and has the following advantages: 1. This extraction system has a separation factor as high as 10 to 20 for zirconium and hafnium in the range of suitable acid concentration. 2. In the scrubbing section, removal of all the hafnium that coexists with zirconium in the organic solvent can be effectively accomplished by using scrubbing solution containing hafnium-free zirconium sulfate. Consequently, hafnium in the zirconium sponge obtained is reduced to less than 50 ppm. 3. The extractant undergoes no chemical changes but is very stable for a long period. In particular, its solubility in water is small, about 20 ppm maximum, posing no environmental pollution problems such as are often caused by other process raffinates. At the present time, the zirconium and hafnium separation operation is very stable, and zirconium sponge made by this process can be applied satisfactorily to nuclear reactors

  1. Preparation of hafnium carbide by chemical vapor deposition

    International Nuclear Information System (INIS)

    Hertz, Dominique.

    1974-01-01

    Hard, adhesive coatings of single-phase hafnium carbide were obtained by chemical vapor reaction in an atmosphere containing hafnium tetrachloride, methane and a large excess of hydrogen. By varying the gas phase composition and temperature the zones of formation of the different solid phases were studied and the growth of elementary hafnium and carbon deposits evaluated separately. The results show that the mechanism of hafnium carbide deposition does not hardly involve phenomene of homogeneous-phase methane decomposition or tetrachloride reduction by hydrogen unless the atmosphere is very rich or very poor in methane with respect to tetrachloride. However, hydrogen acting inversely on these two reactions, affects the stoichiometry of the substance deposited. The methane decomposition reaction is fairly slow, the reaction leading to hafnium carbide deposition is faster and that of tetrachloride reduction by hydrogen is quite fast [fr

  2. Assessing hafnium on hafnia as an oxygen getter

    International Nuclear Information System (INIS)

    O'Hara, Andrew; Demkov, Alexander A.; Bersuker, Gennadi

    2014-01-01

    Hafnium dioxide or hafnia is a wide band gap dielectric used in a range of electronic applications from field effect transistors to resistive memory. In many of these applications, it is important to maintain control over oxygen stoichiometry, which can be realized in practice by using a metal layer, specifically hafnium, to getter oxygen from the adjacent dielectric. In this paper, we employ density functional theory to study the thermodynamic stability of an interface between (100)-oriented monoclinic hafnia and hafnium metal. The nudged elastic band method is used to calculate the energy barrier for migration of oxygen from the oxide to the metal. Our investigation shows that the presence of hafnium lowers the formation energy of oxygen vacancies in hafnia, but more importantly the oxidation of hafnium through the migration of oxygen from hafnia is favored energetically

  3. Flotation separation of hafnium(IV) from aqueous solutions

    International Nuclear Information System (INIS)

    Downey, D.M.; Narick, C.N.; Cohen, T.A.

    1985-01-01

    A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175+181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author)

  4. Method of separating hafnium from zirconium

    International Nuclear Information System (INIS)

    Megy, J.A.

    1980-01-01

    English. A new anhydrous method was developed for separating zirconium and hafnium, which gives higher separation factors and is more economical than previous methods. A molten phase, comprising a solution of unseparated zirconium and hafnium and a solvent metal, is first prepared. The molten metal phase is contacted with a fused salt phase which includes a zirconium salt. Zirconium and hafnium separation is effected by mutual displacement with hafnium being transported from the molten metal phase to the fused salt phase, while zirconium is transported from the fused salt phase to the molten metal phase. The solvent metal is less electropositive than zirconium. Zinc was chosen as the solvent metal, from a group which also included cadmium, lead, bismuth, copper, and tin. The fused salt phase cations are more electropositive than zirconium and were selected from a group comprising the alkali elements, the alkaline earth elements, the rare earth elements, and aluminum. A portion of the zirconium in the molten metal phase was oxidized by injecting an oxidizing agent, chlorine, to form zirconium tetrachlorid

  5. Flotation separation of hafnium(IV) from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Downey, D.M.; Narick, C.N.; Cohen, T.A.

    1985-09-01

    A simple, rapid method for the separation of hafnium from aqueous solutions was investigated using sup(175 + 181)Hf tracer. Cationic hafnium complex ions were floated from dilute acid solutions with sodium lauryl sulfate (SLS) and anionic hafnium complexes were floated from basic and oxalic acid solutions with hexadecyltrimethyl ammonium bromide (HTMAB). The conditions necessary for quantitative recovery of the metal and mechanisms of flotation are described. (author). 21 refs.; 5 figs.

  6. Kinetic studies on the hafnium nad deuterium

    International Nuclear Information System (INIS)

    Bing Wenzeng; Long Xinggui; Zhu Zuliang

    2009-04-01

    Through the method of reaction rate analysis in a constant volume reactor, the time dependence of the pressure drop of the hafnium deuteride formation are studied over a temperature range 573-873 K on a metal hydride thermodynamic and kinetic parameters measuring apparatus. The rate constants of the hafnium deuteride formation, which are 0.0530 s -1 , 0.0452 s -1 , 0.0319 s -1 , 0.0261 s -1 , are calculated at a serial temperatures of 573 K, 673 K, 773 K, 873 K and the initial pressure of 13 kPa. The activation energy of the reaction is (-10.1±1.5) kJ·mol -1 . Comparing the above results with those of titanium deuteride formation on the same measuring apparatus, the kinetic mechanism of the deuteride formation of hafnium and titanium is considered different. It is concluded that the reaction rate of hafnium absorbing deuterium may be controlled by phase transformation and surface oxidation. (authors)

  7. Electronic properties of hafnium oxide: A contribution from defects and traps

    Energy Technology Data Exchange (ETDEWEB)

    Gritsenko, Vladimir A., E-mail: grits@isp.nsc.ru; Perevalov, Timofey V.; Islamov, Damir R., E-mail: damir@isp.nsc.ru

    2016-02-15

    In the present article, we give a review of modern data and latest achievements pertaining to the study of electronic properties of oxygen vacancies in hafnium oxide. Hafnium oxide is a key dielectric for use in many advanced silicon devices. Oxygen vacancies in hafnium oxide largely determine the electronic properties of the material. We show that the electronic transitions between the states due to oxygen vacancies largely determine the optical absorption and luminescent properties of hafnium oxide. We discuss the role of oxygen vacancies as traps that facilitate charge transport in hafnium oxide films. Also, we demonstrate the fact that the electrical conductivity in hafnium oxide is controlled by the phonon-assisted tunnelling of charge carriers between traps that were identified as oxygen vacancies.

  8. Preparation of complexes of zirconium and hafnium tetrachlorides with phosphorus oxychloride

    International Nuclear Information System (INIS)

    McLaughlin, D.F.

    1989-01-01

    This patent describes an improvement in a method for separating hafnium tetrachloride from zirconium tetrachloride where a complex of zirconium-hafnium tetrachlorides and phosphorus oxychloride is prepared from zirconium-hafnium tetrachlorides and the complex of zirconium-hafnium tetrachlorides and phosphorus oxychloride is introduced into a distillation column, which distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and where a hafnium tetrachloride enriched stream is taken from the top of the column and a zirconium enriched tetrachloride stream is taken from the bottom of the column. The improvement comprising: prepurifying the zirconium-hafnium tetrachlorides, prior to preparation of the complex and introduction of the complex into a distillation column, to substantially eliminate iron chloride from the zirconium hafnium tetrachlorides, whereby buildup or iron chloride in the distillation column and in the reboiler is substantially eliminated and the column can be operated in a continuous, stable and efficient manner

  9. Study of fine structure of deformed hafnium

    International Nuclear Information System (INIS)

    Voskresenskaya, L.A.; Petukhova, A.S.; Kovalev, K.S.

    1978-01-01

    Variations in the hafnium fine structure following the cold plastic deformation have been studied. The fine structure condition has been studied through the harmonic analysis of the profile of the X-ray diffraction line, obtained at the DRON-I installation. Received has been the dependence of the crystal lattice microdistortions value on the deformation extent for hafnium. This dependence is compared with the corresponding one for zirconium. It is found out that at all the deformations the microdistortion distribution is uniform. The microdistortion value grows with the increase in the compression. During the mechanical impact higher microdistortions of the crystal lattice occur in the hafnium rather than in zirconium

  10. Properties of filmogen solutions and films of hafnium compounds

    International Nuclear Information System (INIS)

    Sviridova, A.I.

    1986-01-01

    Study on hafnium hydrolizing compound solutions, used for hafnium oxide homogeneous layer formation, is conducted. In particular, electric conductivity, acidity and refractive index were investigated depending on the sal on ether concentration and the storage time. Oxyhafnium nitrate, hafnium chloride in ethanol, dichlorodiethoxyhafnium, hafnium oxychloride were used as initial compounds. Hydrolysis of hafnium compounds in solution occurs partially; further process occurs in the thin layer on the optical element surface; final decomposition is performed under heat treatment. It is ascertained, that alcoholic-aqueous solutions of inorganic salts can be filmogen only at definite acidity, density and viscosity (1.33-2.5 cp.). It is also ascertained that refractive index values and transmission spectral boundary of coatings, produced from alkoxy compound solutions and from chloride salt solutions, are practically the same. Transmittance boundary in ultraviolet region of spectrum of oxide films produced from nitrate and chloride solutions, varies with the heating temperature increase differently

  11. Investigation of ferromagnetism in oxygen deficient hafnium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Krockenberger, Yoshiharu; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Suter, Andreas [PSI, Villingen (Switzerland); Wilhelm, Fabrice; Rogalev, Andrei [ESRF, Grenoble (France)

    2008-07-01

    Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by X-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films.

  12. Titanium zirconium and hafnium coordination compounds with vanillin thiosemicarbazone

    International Nuclear Information System (INIS)

    Konunova, Ts.B.; Kudritskaya, S.A.

    1987-01-01

    Coordination compounds of titanium zirconium and hafnium tetrachlorides with vanillin thiosemicarbazone of MCl 4 x nLig composition, where n=1.5, 4 for titanium and 1, 2, 4 for zirconium and hafnium, are synthesized. Molar conductivity of ethanol solutions is measured; IR spectroscopic and thermochemical investigation are carried out. The supposition about ligand coordination via sulfur and azomethine nitrogen atoms is made. In all cases hafnium forms stable compounds than zirconium

  13. Hafnium - material for chemical apparatus engineering

    International Nuclear Information System (INIS)

    Jennert, D.

    1981-01-01

    This work describes - on the background of available literature - the properties of hafnium in technical quality (DIN-material No. 2.6400) as material for chemical apparatus engineering. The occurence, refining, physical and chemical properties will be described as well as the material behavior. In conclusion, it has been found that there is, at present, sufficient information for the engineering of hafnium which has to be completed by additional investigations for special applications. (orig.) [de

  14. Internal Dosimetry for Inhalation of Hafnium Tritide Aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Inkret, W.C.T.; Schillaci, M.E.; Boyce, M.K.; Cheng, Y.S.; Efurd, D.W.; Little, T.T.; Miller, G.; Musgrave, J.A.; Wermer, J.R

    2001-07-01

    Metal tritides with low dissolution rates may have residence times in the lungs which are considerably longer than the biological half-time normally associated with tritium in body water, resulting in long-term irradiation of the lungs by low energy {beta} particles and bremsstrahlung X rays. Samples of hafnium tritide were placed in a lung simulant fluid to determine approximate lung dissolution rates. Hafnium hydride samples were analysed for particle size distribution with a scanning electron microscope. Lung simulant data indicated a biological dissolution half-time for hafnium tritide on the order of 10{sup 5}d. Hafnium hydride particle sizes ranged between 2 and 10 {mu}m, corresponding to activity median aerodynamic diameters of 5 to 25 {mu}m. Review of in vitro dissolution data, development of a biokinetic model, and determination of secondary limits for 1 {mu}m AMAD particles are presented and discussed. (author)

  15. Titanium(IV), zirconium, hafnium and thorium

    International Nuclear Information System (INIS)

    Brown, Paul L.; Ekberg, Christian

    2016-01-01

    Titanium can exist in solution in a number of oxidation states. The titanium(IV) exists in acidic solutions as the oxo-cation, TiO 2+ , rather than Ti 4+ . Zirconium is used in the ceramics industry and in nuclear industry as a cladding material in reactors where its reactivity towards hydrolysis reactions and precipitation of oxides may result in degradation of the cladding. In nature, hafnium is found together with zirconium and as a consequence of the contraction in ionic radii that occurs due to the 4f -electron shell, the ionic radius of hafnium is almost identical to that of zirconium. All isotopes of thorium are radioactive and, as a consequence of it being fertile, thorium is important in the nuclear fuel cycle. The polymeric hydrolysis species that have been reported for thorium are somewhat different to those identified for zirconium and hafnium, although thorium does form the Th 4 (OH) 8 8+ species.

  16. Perturbed angular correlation

    International Nuclear Information System (INIS)

    Fabris, J.D.

    1977-01-01

    The electric quadrupolar interaction in some hafnium complexes, measured at the metal nucleus level is studied. For that purpose, the technique of γ-γ perturbed angular correlation is used: the frequencies of quadrupolar interaction are compared with some hafnium α-hydroxicarboxilates, namely glycolate, lactate, mandelate and benzylate; the influence of the temperature on the quadrupolar coupling on the hafnium tetramandelate is studied; finally, the effects associated with the capture of thermal neutrons by hafnium tetramandelate are examined locally at the nuclear level. The first group of results shows significant differences in a series of complexes derived from glycolic acid. On the other hand, the substitution of the protons in hafnium tetramandelate structure by some alkaline cations permits to verify a correlation between the variations in the quadrupolar coupling and the electronegativities of the substituent elements. Measurements at high temperatures show that this complex is thermally stable at 100 and 150 0 C. It is possible to see the appearance of two distinct sites for the probe nucleus, after heating the sample at 100 0 C for prolonged time. This fact is attributed to a probable interconversion among the postulated structural isomers for the octacoordinated compounds. Finally, measurements of angular correlation on the irradiated complex show that there is an effective destruction of the target molecule by neutron capture [pt

  17. Ferroelectricity in undoped hafnium oxide

    International Nuclear Information System (INIS)

    Polakowski, Patrick; Müller, Johannes

    2015-01-01

    We report the observation of ferroelectric characteristics in undoped hafnium oxide thin films in a thickness range of 4–20 nm. The undoped films were fabricated using atomic layer deposition (ALD) and embedded into titanium nitride based metal-insulator-metal (MIM) capacitors for electrical evaluation. Structural as well as electrical evidence for the appearance of a ferroelectric phase in pure hafnium oxide was collected with respect to film thickness and thermal budget applied during titanium nitride electrode formation. Using grazing incidence X-Ray diffraction (GIXRD) analysis, we observed an enhanced suppression of the monoclinic phase fraction in favor of an orthorhombic, potentially, ferroelectric phase with decreasing thickness/grain size and for a titanium nitride electrode formation below crystallization temperature. The electrical presence of ferroelectricity was confirmed using polarization measurements. A remanent polarization P r of up to 10 μC cm −2 as well as a read/write endurance of 1.6 × 10 5 cycles was measured for the pure oxide. The experimental results reported here strongly support the intrinsic nature of the ferroelectric phase in hafnium oxide and expand its applicability beyond the doped systems

  18. Hafnium-Based Contrast Agents for X-ray Computed Tomography.

    Science.gov (United States)

    Berger, Markus; Bauser, Marcus; Frenzel, Thomas; Hilger, Christoph Stephan; Jost, Gregor; Lauria, Silvia; Morgenstern, Bernd; Neis, Christian; Pietsch, Hubertus; Sülzle, Detlev; Hegetschweiler, Kaspar

    2017-05-15

    Heavy-metal-based contrast agents (CAs) offer enhanced X-ray absorption for X-ray computed tomography (CT) compared to the currently used iodinated CAs. We report the discovery of new lanthanide and hafnium azainositol complexes and their optimization with respect to high water solubility and stability. Our efforts culminated in the synthesis of BAY-576, an uncharged hafnium complex with 3:2 stoichiometry and broken complex symmetry. The superior properties of this asymmetrically substituted hafnium CA were demonstrated by a CT angiography study in rabbits that revealed excellent signal contrast enhancement.

  19. 40 CFR 471.90 - Applicability; description of the zirconium-hafnium forming subcategory.

    Science.gov (United States)

    2010-07-01

    ... zirconium-hafnium forming subcategory. 471.90 Section 471.90 Protection of Environment ENVIRONMENTAL... POINT SOURCE CATEGORY Zirconium-Hafnium Forming Subcategory § 471.90 Applicability; description of the zirconium-hafnium forming subcategory. This subpart applies to discharges of pollutants to waters of the...

  20. Calorimetric measurements on hafnium titanate

    International Nuclear Information System (INIS)

    Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.

    2012-01-01

    Owing to its desirable nuclear and mechanical properties such as good absorption cross-section for thermal neutrons (105 barns), hafnium titanate (HfTiO 4 ) finds application as control rods for nuclear reactors. An accurate knowledge of the thermo physical properties of this material is necessary for design of control rod and for modeling its performance. Heat capacity is an important thermodynamic property that determines the temperature dependent variation of all other thermodynamic properties. Hence enthalpy increments of hafnium titanate (HfTiO 4 ) were measured in the temperature range 803-1663 K by employing the method of inverse drop calorimetry using high temperature differential calorimeter

  1. Preparation of complexes of zirconium and hafnium tetrachlorides with phosphorus oxychloride

    International Nuclear Information System (INIS)

    Snyder, T.S.; Stoltz, R.A.

    1989-01-01

    This patent describes an improvement in a method for separating hafnium chloride from zirconium chloride using a distillation column, with a hafnium chloride enriched vapor stream taken from the top of the column and a zirconium enriched chloride stream taken from the bottom of the column. The improvement comprising: purifying the zirconium-hafnium chloride in a molten salt purification vessel prior to or after introduction into the distillation column to substantially eliminate iron chloride from the zirconium-hafnium chloride by at least periodically removing iron chloride from the molten salt purification vessel by electrochemically plating iron onto an electrode in the molten salt purification vessel. The molten salt in the molten salt purification vessel consisting essentially of a mixture of chlorides selected from the group consisting of alkali metals, alkaline earth metals, zirconium, hafnium, aluminum, manganese, and zinc

  2. Method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream

    International Nuclear Information System (INIS)

    Snyder, T.S.; Stolz, R.A.

    1992-01-01

    This patent describes a method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream from a sand chlorinator in which the silicon and metals present in sand fed to the chlorinator are converted to chlorides at temperatures over about 800 degrees C. It comprises cooling a vapor stream from a sand chlorinator, the vapor stream containing principally silicon tetrachloride, zirconium tetrachloride, and hafnium tetrachloride contaminated with ferric chloride, to a temperature of from about 335 degrees C to about 600 degrees C; flowing the vapor stream through a gaseous diffusion separative barrier to produce a silicon tetrachloride-containing vapor stream concentrated in zirconium tetrachloride and hafnium tetrachloride and a silicon tetrachloride-containing vapor stream depleted in zirconium tetrachloride and hafnium tetrachloride; adsorbing the ferric chloride in the separative barrier; and recovering the silicon tetrachloride stream concentrated in zirconium tetrachloride and hafnium tetrachloride separately from the silicon tetrachloride stream depleted in zirconium tetrachloride and hafnium tetrachloride

  3. Spectrofluorimetric determination of hafnium and zirconium with 3,7-dihydroxyflavone

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Takushi; Suzuki, Osamu; Seuzuki, Tetsuo; Murata, Akira

    1986-04-01

    The absorptive and fluorescent characteristics of the hafnium and zirconium complexes of 3-hydroxyflavone and its 12 hydroxy and methoxy derivatives have been studied. The fluorescence of the 1:1 hafnium - 3,7-dihydroxyflavone complex (lambdasub(ex.)397 nm,lambdasub(em.) 465 nm) in 3 M hydrochloric acid has been used to determine 2-40 ng ml/sup -1/ of hafnium. The fluorescence of the 1:1 zirconium - 3,7-dihydroxyflavone complex (lambdasub(ex.) 395 nm, lambda sub(em.) 465 nm) at pH 2.0 in 0.02 M sulphate solution has been used to determine 2-40 ng ml/sup -1/ of zirconium. These methods are very sensitive and can be used for the simultaneous determination of hafnium and zirconium with an error of about 5%.

  4. Molten salt extractive distillation process for zirconium-hafnium separation

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1989-01-01

    This patent describes an improvement in a process for zirconium-hafnium separation. It utilizes an extractive distillation column with a mixture of zirconium and hafnium tetrachlorides introduced into a distillation column having a top and bottom with hafnium enriched overheads taken from the top of the column and a molten salt solvent circulated through the column to provide a liquid phase, and with molten salt solvent containing zirconium chloride being taken from the bottom of the distillation column. The improvements comprising: utilizing a molten salt solvent consisting principally of lithium chloride and at least one of sodium, potassium, magnesium and calcium chlorides; stripping of the zirconium chloride taken from the bottom of the distillation column by electrochemically reducing zirconium from the molten salt solvent; and utilizing a pressurized reflux condenser on the top of the column to add the hafnium chloride enriched overheads to the molten salt solvent previously stripped of zirconium chloride

  5. 40 CFR 421.330 - Applicability: Description of the primary zirconium and hafnium subcategory.

    Science.gov (United States)

    2010-07-01

    ... primary zirconium and hafnium subcategory. 421.330 Section 421.330 Protection of Environment ENVIRONMENTAL... CATEGORY Primary Zirconium and Hafnium Subcategory § 421.330 Applicability: Description of the primary zirconium and hafnium subcategory. The provisions of this subpart are applicable to discharges resulting...

  6. Design and fabrication of hafnium tube to control the power of the irradiation test fuel in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. H.; Lee, C. B.; Kim, Y. M.; Yang, Y. S.; Jung, Y. H

    2003-05-01

    For the irradiation test at HANARO, non-instrumentation capsule was manufactured and hafnium tube was used to control LHGR of HANARO. Hafnium tube can control the irradiation condition of HANARO similar to that of commercial reactor. Hafnium tube thickness was determined by the LHGR calculated at OR-4 irradiation hole to be installed the non-instrumented capsule. To fabricate the hafnium tube with hafnium plate, the fabrication method was determined by using the hafnium mechanical properties. And the tensile strength of hafnium was confirmed by tensile test. This report is confirmed the LHGR control at the OR-4 and the Hafnium fabrication for in used which the AFPCAP non-instrumented irradiation capsule.

  7. Use of X-ray fluorescence analysis for the determination of hafnium in zircalloys

    International Nuclear Information System (INIS)

    Sato, I.M.; Salvador, V.L.R.; Lordello, A.R.

    1985-01-01

    The determination of hafnium at trace levels (ppm) in the presence of zirconium by X-ray fluorescence technique is presented. The samples were prepared in the form of double-layer pellets, with boric acid as the binding material. The most sensitive first order line of hafnium HfLα (0.157 nm), which is used analyticaly, has approximately 67% overlapping with second order line of zirconium ZrKα 1 , (0.079 nm). As the excitation potencial of zirconium is larger than hafnium, the best condition was selected, so that the interference of zirconium intensity would not be significant in hafnium analytical line. The method allowed the determination of hafnium above 5.0 ppm (LLd = 1.5 ppm) with an accuracy of less than 10%. (Author) [pt

  8. Use of hafnium in control bars of nuclear reactors

    International Nuclear Information System (INIS)

    Ramirez S, J.R.; Alonso V, G.

    2003-01-01

    Recently the use of hafnium as neutron absorber material in nuclear reactors has been reason of investigation by virtue of that this material has nuclear properties as to the neutrons absorption and structural that can prolong the useful life of the control mechanisms of the nuclear reactors. In this work some of those more significant hafnium properties are presented like nuclear material. Also there are presented calculations carried out with the HELIOS code for fuel cells of uranium oxide and of uranium and plutonium mixed oxides under controlled conditions with conventional bars of boron carbide and also with similar bars to which are substituted the absorbent material by metallic hafnium, the results are presented in this work. (Author)

  9. Corrosion potentials of hafnium in molten alkaline-earth metal chlorides

    International Nuclear Information System (INIS)

    Kovalik, O.Yu.; Tkhaj, V.D.

    2000-01-01

    Corrosion potentials of hafnium in molten calcium, strontium and barium chlorides are measured and their temperature dependences are determined. It is stated that the corrosion potential of hafnium becomes more electropositive with an increase of the environment temperature. If the temperature is the same the potential shifts to the interval of more electronegative values in the row of CaCl 2 , SrCl 2 , BaCl 2 which corresponds to a lesser corrosion rate in environments positioned from left to right. the comparison of hafnium corrosion potentials with previously measured values for titanium and zirconium shows that a metal activity decrease results in a more electronegative corrosion potential [ru

  10. Electronic structure of pentacene on hafnium studied by ultraviolet photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Kang, Seong Jun; Yi, Yeon Jin; Kim, Chung Yi; Whang, Chung Nam

    2005-01-01

    The electronic structure of pentacene on hafnium, which is a low work function metal, was analyzed by using ultraviolet photoelectron spectroscopy. The energy level alignment was studied by using the onset of the highest occupied molecular orbital level and the shift of the vacuum level of the pentacene layer, which was deposited on a clean hafnium surface in a stepwise manner. The measured onset of the highest occupied molecular orbital energy level was 1.52 eV from the Fermi level of hafnium. The vacuum level was shifted 0.28 eV toward higher binding energy with additional pentacene layers, which means an interfacial dipole exists at the interface between pentacene and hafnium. We confirm that a small electron injection barrier can be achieved by inserting a low work function metal in a pentacene thin-film transistor.

  11. Synthesis of Hafnium-Based Ceramic Materials for Ultra-High Temperature Aerospace Applications

    Science.gov (United States)

    Johnson, Sylvia; Feldman, Jay

    2004-01-01

    This project involved the synthesis of hafnium (Hf)-based ceramic powders and Hf-based precursor solutions that were suitable for preparation of Hf-based ceramics. The Hf-based ceramic materials of interest in this project were hafnium carbide (with nominal composition HE) and hafnium dioxide (HfO2). The materials were prepared at Georgia Institute of Technology and then supplied to research collaborators Dr. Sylvia Johnson and Dr. Jay Feldman) at NASA Ames Research Center.

  12. Application of hafnium hydride control rod to large sodium cooled fast breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Kazumi, E-mail: kazumi_ikeda@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Moriwaki, Hiroyuki, E-mail: hiroyuki_moriwaki@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Ohkubo, Yoshiyuki, E-mail: yoshiyuki_okubo@mfbr.mhi.co.jp [Mitsubishi FBR Systems, Inc., 34-17, Jingumae 2-Chome, Shibuya-ku, Tokyo 150-0001 (Japan); Iwasaki, Tomohiko, E-mail: tomohiko.iwasaki@qse.tohoku.ac.jp [Department of Quantum Science and Energy Engineering, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai-shi, Miyagi-ken 980-8579 (Japan); Konashi, Kenji, E-mail: konashi@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Narita-cho, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki-ken 311-1313 (Japan)

    2014-10-15

    Highlights: • Application of hafnium hydride control rod to large sodium cooled fast breeder reactor. • This paper treats application of an innovative hafnium hydride control rod to a large sodium cooled fast breeder reactor. • Hydrogen absorption triples the reactivity worth by neutron spectrum shift at H/Hf ratio of 1.3. • Lifetime of the control rod quadruples because produced daughters of hafnium isotopes are absorbers. • Nuclear and thermal hydraulic characteristics of the reactor are as good as or better than B-10 enriched boron carbide. - Abstract: This study treats the feasibility of long-lived hafnium hydride control rod in a large sodium-cooled fast breeder reactor by nuclear and thermal analyses. According to the nuclear calculations, it is found that hydrogen absorption of hafnium triples the reactivity by the neutron spectrum shift at the H/Hf ratio of 1.3, and a hafnium transmutation mechanism that produced daughters are absorbers quadruples the lifetime due to a low incineration rate of absorbing nuclides under irradiation. That is to say, the control rod can function well for a long time because an irradiation of 2400 EFPD reduces the reactivity by only 4%. The calculation also reveals that the hafnium hydride control rod can apply to the reactor in that nuclear and thermal characteristics become as good as or better than 80% B-10 enriched boron carbide. For example, the maximum linear heat rate becomes 3% lower. Owing to the better power distribution, the required flow rate decreases approximately by 1%. Consequently, it is concluded on desk analyses that the long lived hafnium hydride control rod is feasible in the large sodium-cooled fast breeder reactor.

  13. X-Ray Photoemission Study of the Oxidation of Hafnium

    International Nuclear Information System (INIS)

    Chourasia, R.; Hickman, J.L.; Miller, R.L.; Nixon, G.A.; Seabolt, M.A.

    2011-01-01

    About 20 angstrom of hafnium were deposited on silicon substrates using the electron beam evaporation technique. Two types of samples were investigated. In one type, the substrate was kept at the ambient temperature. After the deposition, the substrate temperature was increased to 100, 200, and 300 degree C. In the other type, the substrate temperature was held fixed at some value during the deposition. For this type, the substrate temperatures used were 100, 200, 300, 400, 500, 550, and 600 degree C. The samples were characterized in situ by the technique of X-ray photoelectron spectroscopy. No trace of elemental hafnium is observed in the deposited overlayer. Also, there is no evidence of any chemical reactivity between the overlayer and the silicon substrate over the temperature range used. The hafnium overlayer shows a mixture of the dioxide and the suboxide. The ratio of the suboxide to dioxide is observed to be more in the first type of samples. The spectral data indicate that hafnium has a strong affinity for oxygen. The overlayer gets completely oxidized to form HfO 2 at substrate temperature around 300 degree C for the first type of samples and at substrate temperature greater than 550 degree C for the second type

  14. X-Ray Photoemission Study of the Oxidation of Hafnium

    Directory of Open Access Journals (Sweden)

    A. R. Chourasia

    2009-01-01

    Full Text Available About 20 Å of hafnium were deposited on silicon substrates using the electron beam evaporation technique. Two types of samples were investigated. In one type, the substrate was kept at the ambient temperature. After the deposition, the substrate temperature was increased to 100, 200, and 300∘C. In the other type, the substrate temperature was held fixed at some value during the deposition. For this type, the substrate temperatures used were 100, 200, 300, 400, 500, 550, and 600∘C. The samples were characterized in situ by the technique of X-ray photoelectron spectroscopy. No trace of elemental hafnium is observed in the deposited overlayer. Also, there is no evidence of any chemical reactivity between the overlayer and the silicon substrate over the temperature range used. The hafnium overlayer shows a mixture of the dioxide and the suboxide. The ratio of the suboxide to dioxide is observed to be more in the first type of samples. The spectral data indicate that hafnium has a strong affinity for oxygen. The overlayer gets completely oxidized to form HfO2 at substrate temperature around 300∘C for the first type of samples and at substrate temperature greater than 550∘C for the second type.

  15. High temperature diffusion of hafnium in tungsten and a tungsten-hafnium carbide alloy

    International Nuclear Information System (INIS)

    Ozaki, Y.; Zee, R.H.

    1994-01-01

    Refractory metals and ceramics are used extensively in energy systems due to their high temperature properties. This is particularly important in direct conversion systems where thermal to electric conversion efficiency is a direct function of temperature. Tungsten, which has the highest melting temperature among elemental metals, does not possess sufficient creep resistance at temperature above 1,600 K. Different dispersion strengthened tungsten alloys have been developed to extend the usefulness of tungsten to higher temperatures. One of these alloys, tungsten with 0.4 mole percent of finely dispersed HfC particles (W-HfC), has the optimum properties for high temperature applications. Hafnium carbide is used as the strengthening agent due to its high chemical stability and its compatibility with tungsten. The presence of HfC particles retards the rate of grain growth as well as restricting dislocation motion. Both of which are beneficial for creep resistance. The long term behavior of this alloy depends largely on the evolution of its microstructure which is governed by the diffusion of its constituents. Data on the diffusion of carbon in tungsten and tungsten self-diffusion are available, but no direct measurements have been made on the diffusion of hafnium in tungsten. The only diffusion data available are estimated from a coarsening study and these data are highly unreliable. In this study, the diffusion behavior of hafnium in pure tungsten and in a W-HfC alloy was directly measured by means of Secondary Ion Mass Spectroscopy (SIMS). The selection of the W-HfC alloy is due to its importance in high temperature engineering applications, and its higher recrystallization temperature. The presence of HfC particles in tungsten restricts grain growth resulting in better high temperature creep resistance. The higher recrystallization temperature allows measurements to be made over a wider range of temperatures at a relatively constant grain size

  16. Elaboration and characterisation of yttrium oxide and hafnium oxide powders by the sol-gel process

    International Nuclear Information System (INIS)

    Hours, T.

    1988-01-01

    The two classical sol-gel processes, colloidal and polymeric are studied for the preparation of yttrium oxide and hafnium oxide high performance powders. In the colloidal process, controlled and reproducible conditions for the preparation of yttrium oxide and hafnium oxide sols from salts or alkoxides are developed and the hydrothermal synthesis monodisperse hafnium oxide colloids is studied. The polymeric process is studied with hafnium ethyl-hexylate, hydrolysis kinetics for controlled preparation of sols and gels is investigated. Each step of preparation is detailed and powders obtained are characterized [fr

  17. Modelling of Zirconium and Hafnium separation using continuous annular chromatography

    International Nuclear Information System (INIS)

    Moch-Setyadji; Endang Susiantini

    2014-01-01

    Nuclear degrees of zirconium in the form of a metal alloy is the main material for fuel cladding of NPP. Zirconium is also used as sheathing UO 2 kernel in the form of ZrC as a substitute of SiC in the fuel elements of High Temperature Reactor (HTR). Difficulty separating hafnium from zirconium because it has a lot of similarities in the chemical properties of Zr and Hf. Annular chromatography is a device that can be used for separating of zirconium and hafnium to obtain zirconium nuclear grade. Therefore, it is necessary to construct the mathematical modelling that can describe the separation of zirconium and hafnium in the annular chromatography containing anion resin dowex-1X8. The aim of research is to perform separation simulation by using the equilibrium model and mass transfer coefficient resulted from research. Zr and Hf feed used in this research were 26 and 1 g/l, respectively. Height of resin (L), angular velocity (ω) and the superficial flow rate (uz) was varied to determine the effect of each parameter on the separation of Zr and Hf. By using Kd and Dv values resulted previous research. Simulation results showed that zirconium and hafnium can be separated using a continuous annular chromatography with high resin (long bed) 50 cm, superficial flow rate of 0.001 cm/s, the rotation speed of 0.006 rad/min and 20 cm diameter annular. In these conditions the results obtained zirconium concentration of 10,303.226 g/m 3 and hafnium concentration of 12.324 g/m 3 (ppm). (author)

  18. Joint titrimetric determination of zirconium and hafnium

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Botbol, Moises; Bianco de Salas, G.N.; Cornell de Casas, M.I.

    1980-01-01

    A method for the joint titrimetric determination of zirconium and hafnium, which are elements of similar chemical behaviour, is described. The disodic salt of the ethylendiaminetetracetic acid (EDTA) is used for titration, while xilenol orange serves as final point indicator. Prior to titration it is important to evaporate with sulfuric acid, the solution resulting from the zirconium depolymerization process, to adjust the acidity and to eliminate any interferences. The method, that allows the quick and precise determination of zirconium and hafnium in quantities comprised between 0.01 and mg, was applied to the analysis of raw materials and of intermediate and final products in the fabrication of zirconium sponge and zircaloy. (M.E.L.) [es

  19. Compositional characterization of hafnium alloy used as control rod material in nuclear reactor

    International Nuclear Information System (INIS)

    Sharma, P.K.; Bassan, M.K.T.; Avhad, D.K.; Singhal, R.K.

    2014-01-01

    Hafnium (Hf) is a heavy, steel-gray metal in the reactive metals group that is very closely related to zirconium (Zr) and forms a continuous solid-solution at all concentrations of zirconium and hafnium. Hafnium occurs naturally with zirconium at a ratio of approximately 1:50 and is produced exclusively as a co-product of nuclear-grade zirconium. It is used in a variety of applications where few substitutes are available. Thus with its relatively high thermal neutron absorption cross-section, hafnium's biggest application is as control rod material in nuclear reactors. During this work, major (Zirconium (Zr), Cobalt (Co) and Molybdenum (Mo)) and trace ((Iron (Fe), Nickel (Ni) and Titanium (Ti)) elements were measured in the bulk matrices of Hf. These materials are also associated with other impurities such as O, N, H etc.

  20. Bond formation in hafnium atom implantation into SiC induced by high-energy electron irradiation

    International Nuclear Information System (INIS)

    Yasuda, H.; Mori, H.; Sakata, T.; Naka, M.; Fujita, H.

    1992-01-01

    Bilayer films of Hf (target atoms)/α-SiC (substrate) were irradiated with 2 MeV electrons in an ultra-high voltage electron microscope (UHVEM), with the electron beam incident on the hafnium layer. As a result of the irradiation, hafnium atoms were implanted into the SiC substrate. Changes in the microstructure and valence electronic states associated with the implantation were studied by a combination of UHVEM and Auger valence electron spectroscopy. The implantation process is summarized as follows. (1) Irradiation with 2 MeV electrons first induces a crystalline-to-amorphous transition in α-SiC. (2) Hafnium atoms which have been knocked-off from the hafnium layer by collision with the 2 MeV electrons are implanted into the resultant amorphous SiC. (3) The implanted hafnium atoms make preferential bonding to carbon atoms. (4) With continued irradiation, the hafnium atoms repeat the displacement along the beam direction and the subsequent bonding with the dangling hybrids of carbon and silicon. The repetition of the displacement and subsequent bonding lead to the deep implantation of hafnium atoms into the SiC substrate. It is concluded that implantation successfully occurs when the bond strength between a constituent atom of a substrate and an injected atom is stronger than that between constituent atoms of a substrate. (Author)

  1. Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

    International Nuclear Information System (INIS)

    MJ Trbovich; DP Barry; RE Slovacck; Y Danon; RC Block; JA Burke; NJ Drindak; G Leinweber; RV Ballad

    2004-01-01

    The focus of this work is to determine resonance parameters for stable hafnium isotopes in the 0.005-200 eV region, with special emphasis on the overlapping 176 Hf and 178 Hf resonances near 8 eV. The large neutron cross section of hafnium, combined with its corrosion resistance and excellent mechanical properties, make it a useful material for controlling nuclear reactions. Experiments measuring neutron capture and transmission were performed at the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) using the time of flight method. 6 Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m. Capture experiments were done using a sixteen section NaI(Tl) multiplicity detector at a flight path length of 25 m. These experiments utilized various thicknesses of metallic and isotopically-enriched liquid samples. The liquid samples were designed to provide information on the 176 Hf and 178 Hf contributions to the 8 eV doublet without saturation. Data analysis was done using the R-matrix Bayesian code SAMMY version M6 beta. SAMMY is able to account for experimental resolution effects for each of the experimental setups at the RPI LINAC, and also can correct for multiple scattering effects in neutron capture yield data. The combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005-200 eV. Resonance integrals were calculated along with errors for each hafnium isotope using the NJOY [1] and INTER [2] codes. The isotopic resonance integrals calculated were significantly different than previously published values; however the calculated elemental hafnium resonance integral changed very little

  2. Zirconium and hafnium in the southeastern Atlantic States

    Science.gov (United States)

    Mertie, J.B.

    1958-01-01

    The principal source of zirconium and hafnium is zircon, though a minor source is baddeleyite, mined only in Brazil. Zircon is an accessory mineral in igneous, metamorphic, and sedimentary rocks, but rarely occurs in hardrock in minable quantities. The principal sources of zircon are therefore alluvial deposits, which are mined in many countries of five continents. The principal commercial deposits in the United States are in Florida, though others exist elsewhere in the southeastern Coastal Plain. The evidence indicates that conditions for the accumulation of workable deposits of heavy minerals were more favorable during the interglacial stages of the Pleistocene epoch than during Recent time. Therefore detrital ores of large volume and high tenor are more likely to be found in the terrace deposits than along the present beaches. Other concentrations of heavy minerals, however, are possible at favored sites close to the Fall Line where the Tuscaloosa formation rests upon the crystalline rocks of the Piedmont province. A score of heavy and semiheavy minerals occur in the detrital deposits of Florida, but the principal salable minerals are ilmenite, leucoxene, rutile, and zircon, though monazite and staurolite are saved at some mining plants. Commercial deposits of heavy minerals are generally required to have a tenor of 4 percent, though ores with a lower tenor can be mined at a profit if the content of monazite is notably high. The percentages of zircon in the concentrates ranges from 10 to 16 percent, and in eastern Florida from 13 to 15 percent. Thus the tenor in zircon of the ore-bearing sands ranges from 0.4 to 0.6 percent. The content of hafnium in zircon is immaterial for many uses, but for some purposes very high or very low tenors in hafnium are required. Alluvial zircon cannot be separated into such varieties, which, if needed, must be obtained from sources in bedrock. It thus becomes necessary to determine the Hf : Zr ratios in zircon from many kinds of

  3. Niobium and hafnium grown on porous membranes

    International Nuclear Information System (INIS)

    Morant, C.; Marquez, F.; Campo, T.; Sanz, J.M.; Elizalde, E.

    2010-01-01

    In this work we report on a method for fabricating highly ordered nanostructures of niobium and hafnium metals by physical vapour deposition using two different templates: anodized aluminum oxide membranes (AAO) and zirconium onto AAO membranes (Zr/AAO). The growth mechanism of these metal nanostructures is clearly different depending on the material used as a template. A different morphology was obtained by using AAO or Zr/AAO templates: when the metal is deposited onto AAO membranes, nanospheres with ordered hexagonal regularity are obtained; however, when the metal is deposited onto a Zr/AAO template, highly ordered nanocones are formed. The experimental approach described in this work is simple and suitable for synthesizing nanospheres or nanoholes of niobium and hafnium metals in a highly ordered structure.

  4. Analytical study of zirconium and hafnium α-hydroxy carboxylates

    International Nuclear Information System (INIS)

    Terra, V.R.

    1991-01-01

    The analytical study of zirconium and hafnium α-hydroxy carboxylates was described. For this purpose dl-mandelic, dl-p-bromo mandelic, dl-2-naphthyl glycolic, and benzilic acids were prepared. These were used in conjunction with glycolic, dl-lactic, dl-2-hydroxy isovaleric, dl-2-hydroxy hexanoic, and dl-2-hydroxy dodecanoic acids in order to synthesize the zirconium(IV) and hafnium(IV) tetrakis(α-hydroxy carboxylates). The compounds were characterized by melting point determination, infrared spectroscopy, thermogravimetric analysis, calcination to oxides and X-ray diffractometry by the powder method. (C.G.C)

  5. High temperature evaporation of titanium, zirconium and hafnium carbides

    International Nuclear Information System (INIS)

    Gusev, A.I.; Rempel', A.A.

    1991-01-01

    Evaporation of cubic nonstoichiometric carbides of titanium, zirconium and hafnium in a comparatively low-temperature interval (1800-2700) with detailed crystallochemical sample certification is studied. Titanium carbide is characterized by the maximum evaporation rate: at T>2300 K it loses 3% of sample mass during an hour and at T>2400 K titanium carbide evaporation becomes extremely rapid. Zirconium and hafnium carbide evaporation rates are several times lower than titanium carbide evaporation rates at similar temperatures. Partial pressures of metals and carbon over the carbides studied are calculated on the base of evaporation rates

  6. Determination of hafnium, molybdenum, and vanadium in niobium and niobium-based alloys by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Ide, Kunikazu; Kobayashi, Takeshi; Sudo, Emiko.

    1985-01-01

    The analytical procedure is as follows: Weigh 1 g of a sample and put it into a 100 cm 3 PTFE beaker. Add 5 ml of distilled water and 5 ml of hydrofluoric acid, and then heat the solution on a hot plate, adding 3 ml of nitric acid dropwise. Dilute the solution to 100 cm 3 with distilled water. When hafnium is determined, add 2 g of diammonium titanium hexafluoride ((NH 4 ) 2 TiF 6 )) before dilution. Working standard solutions are prepared by adding the stock standard solutions of hafnium, molybdenum, and vanadium into niobium solutions. When hafnium is determined, add 2 g of (NH 4 ) 2 TiF 6 and the alloying elements in amounts corresponding to those in sample solutions into the working standard solutions. The tolerable amounts of hydrofluoric acid were 2.9 M, 2.1 M, and 3.1 M and those of nitric acid were 1.0 M, 1.6 M, and 1.6 M for hafnium, molybdenum, and vanadium, respectively. It was found that (NH 4 ) 2 TiF 6 greatly increased the sensitivity for hafnium determination. Niobium showed minus effect for hafnium and plus effect for molybdenum and vanadium. The atomic absorption of molybdenum and vanadium were not influenced by the presence of 20 % of each alloying element, while the atomic absorption of hafnium was given plus effect by 20 % of zirconium, iron, cobalt, nickel, manganese, chromium or vanadium and minus effect by 20 % tungsten. The analytical values of hafnium, molybdenum, and vanadium in niobium-based alloys by this method showed a good agreement with those by X-ray fluorescence analysis. The lower limits of determination (S/N=2) were 0.05, 0.001, and 0.002 % and the relative standard deviation were 3, 1, and 1.5 % for hafnium, molybdenum, and vanadium, respectively. (author)

  7. Differential perturbed angular correlation: use of physico-chemical study of some hafnium complexes derivates of hydroxy acids and EDTA

    International Nuclear Information System (INIS)

    Silveira, J.G. da.

    1981-01-01

    Measures of quadrupolar interaction to nucleus level of the metal, in some hafnium complexes are presented, including the analysis by combustion, microanalysis, infrared spectroscopy and thermogravimetry. The hyperfine interaction parameters, the temperature effects and the thermal neutrons capture effects over the irradiated Hf Y (Y = EDTA) are also studied. (author)

  8. Separation of zirconium from hafnium by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Felipe, Elaine C.B.; Palhares, Hugo G.; Ladeira, Ana Claudia Q., E-mail: elainecfelipe@yahoo.com.br, E-mail: hugopalhares@gmail.com, E-mail: ana.ladeira@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Zirconium and hafnium are two of the most important metals for the nuclear industry. Hafnium occurs in all zirconium ores usually in the range 2 - 3%. However, for the most nuclear industry applications, it is necessary to use a zirconium of extremely pure level. The current work consists in the separation of zirconium and hafnium by the ion exchange method in order to obtain a zirconium concentrate of high purity. The zirconium and hafnium liquors were produced from the leaching of the Zr(OH){sub 4} and Hf(OH){sub 4} with nitric acid for 24 hours. From these two liquors it was prepared one solution containing 7.5 x 10{sup -2} mol L{sup -1} of Zr and 5.8 x 10{sup -3} mol L{sup -1} of Hf with acidity of 1 M. Ion exchange experiments were carried out in batch with the resins Dowex 50WX4, Dowex 50WX8 100, Dowex 50WX8 50, Amberlite IR-120 and Marathon C at constant temperature 28 deg C. Other variables such as, acidity and agitation were kept constant. The data were adjusted to Langmuir equation in order to calculate the maximum loading capacity (q{sub max}) of the resins, the distribution coefficient (K{sub d}) for Zr and Hf and the separation factor (α{sub Hf}{sup Zr} ). The results of maximum loading capacity (q{sub max}) for Zr and Hf, in mmol g{sup -}1, showed that the most suitable resins for columns experiments are: Dowex 50WX4 50 (q{sub max} Z{sub r} = 2.21, Hf = 0.18), Dowex 50WX8 50 (q{sub max} Zr = 1.89, Hf = 0.13) and Amberlite (q{sub max} Zr = 1.64, Hf = 0.12). However, separations factors, α{sub Hf}{sup Zr}, showed that the resins are not selective. (author)

  9. On the stabilization of niobium(V) solutions by zirconium(IV) and hafnium(IV)

    DEFF Research Database (Denmark)

    Sørensen, E.; Bjerre, A.B.

    1992-01-01

    Niobium cannot be separated from zirconium or hafnium when these elements occur together in solution with common anions such as chloride and sulphate. This is ascribed to the co-polymerization of niobium(V) and the hydrolysed ionic species of zirconium(IV) and hafnium(IV) to form colloidal...

  10. Analysis of hafnium in zirconium alloys

    International Nuclear Information System (INIS)

    Kondo, Isao; Sakai, Fumiaki; Ohuchi, Yoshifusa; Nakamura, Hisashi

    1977-01-01

    It is required to analyse alloying components and impurity elements in the acceptance analysis of zirconium alloys as the material for fuel cladding tubes and pressure tubes for advanced thermal reactors. Because of extreme similarity in chemical properties between zirconium and hafnium, about 100 ppm of hafnium is usually contained in zirconium alloys. Zircaloy-2 alloy and 2.5% Nb-zirconium with the addition of hafnium had been prepared as in-house standard samples for rapid analysis. Study was made on fluorescent X-ray analysis and emission spectral analysis to establish the analytical method. By using these in-house standard samples, acceptance analysis was successfully carried out for the fuel cladding tubes for advanced thermal reactors. Sulfuric acid solution was prepared from JAERI-Z 1, 2 and 3, the standard sample for zircaloy-2 prepared by the Analytical Committee on Nuclear Fuel and Reactor Materials, JAERI, and zirconium oxide (Hf 1 ppm/Zr). Standard Hf solution was added to the sulfuric acid solution step by step, to make up a series of the standard oxide samples by the precipitation process. By the use of these standard samples, the development of the analytical method and joint analysis were made by the three-member analytical technique research group including PNC. The analytical precision for the fluorescent X-ray analysis was improved by attaching a metallic yttrium filter to the window of an X-ray tube so as to suppress the effect due to zirconium matrix. The variation factor of the joint analysis was about 10% to show good agreement, and the indication value was determined. (Kobatake, H.)

  11. Knight shift in scandium and its alloys with hafnium and titanium

    International Nuclear Information System (INIS)

    Chachkhiani, Z.B.; Chechernikov, V.I.; Martynova, L.F.; Nidel'ko, V.I.; Chachkhiani, L.G.; Georgadze, G.S.

    1981-01-01

    Results of the investigation of NMR on 45 Sc nuclei and magnetic susceptibility of scandium and its solid solutions with titanium and hafnium are presented. It is shown that the existing hybridization of S and d zones in pure scandium and its alloys with titanium and hafnium affects the Knight shift reducing the value of the contact contribution. The temperature behaviour of the Knight shift from the temperature dependence and spin susceptibility of collectivized d electrons [ru

  12. Composition and microstructure of zirconium and hafnium germanates obtained by different chemical routes

    International Nuclear Information System (INIS)

    Utkin, A.V.; Prokip, V.E.; Baklanova, N.I.

    2014-01-01

    The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. The products were characterized using high-temperature X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal (TG/DTA) analysis. To investigate the phase composition and stoichiometry of compounds the unit cell parameters were refined by full-profile Rietveld XRD analysis. The morphology of products and its evolution during high-temperature treatment was examined by SEM analysis. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. The ceramic route requires a multi-stage high-temperature treatment to obtain zirconium and hafnium germanates of 95% purity or more. Also, there are strong diffusion limitations to obtain hafnium germanate Hf 3 GeO 8 by ceramic route. On the contrary, the co-precipitation route leads to the formation of nanocrystalline single phase germanates of stoichiometric composition at a relatively low temperatures (less than 1000 °C). The results of quantitative XRD analysis showed the hafnium germanates are stoichiometric compounds in contrast to zirconium germanates that form a set of solid solutions. This distinction may be related to the difference in the ion radii of Zr and Hf. - Graphical abstract: The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. Display Omitted - Highlights: • Zr and Hf germanates were synthesized by ceramic and co-precipitation routes. • The morphology of products depends on the synthesis parameters. • Zirconium germanates forms a set of solid solutions. • Hafnium germanates are stoichiometric compounds

  13. Recovery of hafnium radioisotopes from a proton irradiated tantalum target

    International Nuclear Information System (INIS)

    Taylor, W.A.; Garcia, J.G.; Hamilton, V.T.; Heaton, R.C.; Jamriska, D.J.; Ott, M.A.; Philips, D.R.; Radzinski, S.D.

    1998-01-01

    The 178m2 Hf nucleus, with its long half-life (31 y) and high-spin isomeric state (16 + ) is desired for new and exotic nuclear physics studies. The Los Alamos Radioisotope Program irradiated a kilogram of natural tantalum at the Los Alamos Meson Physics Facility in early 1981. After fifteen years of decay, this target was ideal for the recovery of 178m2 Hf. There was more than a millicurie of 178m2 Hf produced during this irradiation and there has been a sufficient period of time for most of the other hafnium radioisotopes to decayed away. Traditionally, separation techniques for recovering hafnium isotopes from tantalum targets employ solvent extractions with reagents that are considered hazardous. These techniques are no longer condoned because they generate a mixed-waste (radioactive and hazardous components) that can not be treated for disposal. In this paper we describe a new and unique procedure for the recovery of hafnium radioisotopes from a highly radioactive, proton irradiated, tantalum target using reagents that do not contribute a hazardous waste component. (author)

  14. Molecular structure, vibrational, HOMO-LUMO, MEP and NBO analysis of hafnium selenite

    Science.gov (United States)

    Yankova, Rumyana; Genieva, Svetlana; Dimitrova, Ginka

    2017-08-01

    In hydrothermal condition hafnium selenite with estimated chemical composition Hf(SeO3)2·n(H2O) was obtained and characterized by powder X-Ray diffraction, IR spectroscopy and thermogravimetrical analysis. The composition of the obtained crystalline phase was established as dihydrate of tetraaqua complex of the hafnium selenite [Hf(SeO3)2(H2O)4]·2H2O. The results of the thermogravimetrical analysis are shown that the two hydrated water molecules are released in the temperature interval 80-110°C, while the four coordinated water molecules - at 210-300°C. By DFT method, with Becke's three parameter exchange-functional combined with gradient-corrected correlation functional of Lee, Yang and Parr and 6-31G(d), 6-311 + G(d,p) basis sets and LANL2DZ for Hf atom were calculated the molecular structure, vibrational frequencies and thermodynamic properties of the structure. The UV-Vis spectra and electronic properties are presented. The energy and oscillator strength calculated by time-dependent density functional theory corresponds well with the experimental ones. Molecular electrostatic potential (MEP) was performed. Mulliken population analysis on atomic charges was also calculated. The stability and intramolecular interactions are interpreted by NBO analysis.

  15. Investigation of colourless complexes of thorium, hafnium and zirconium

    International Nuclear Information System (INIS)

    Kiciak, S.; Stefanowicz, T.; Gontarz, H.; Swit, Z.

    1980-01-01

    The investigations conducted in the Institute of General Chemistry of Poznan Technical University in partial cooperation with Kharkhof Technical University related with thorium, hafnium and zirconium complexes are reviewed. (author)

  16. Separation process of zirconium and hafnium; Procede de separation du zirconium et du hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Hure, J; Saint-James, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    About the separation different processes of zirconium-hafnium, the extraction by solvent in cross-current is the most easily the process usable on an industrial scale. It uses tributyl phosphate as solvent, diluted with white spirit to facilitate the decanting. Some exploratory tests showed that nitric environment seemed the most favorable for extraction; but a lot of other factors intervene in the separation process. We studied the influence of the acidity successively, the NO{sub 3}{sup -} ions concentration, the role of the cation coming with NO{sub 3}{sup -}, as well as the influence of the concentration of zirconium in the solution on the separation coefficient {beta} = {alpha}{sub Zr} / {alpha}{sub Hf}. (M.B.) [French] Des differents procedes de separation zirconium-hafnium, l'extraction par solvant en contre-courant est le procede le plus facilement utilisable a l'echelle industrielle. On utilise comme solvant le phosphate de tributyle, dilue avec du white spirit pour faciliter les decantations. Des essais preliminaires ont montre que le milieu nitrique semblait le plus favorable a l'extraction; mais beaucoup d'autres facteurs interviennent dans le processus de separation. Nous avons etudie successivement l'influence de l'acidite, celle de la concentration en ions NO{sub 3}{sup -}, le role du cation accompagnant NO{sub 3}{sup -}, ainsi que l'influence de la concentration en zirconium de la solution sur le coefficient de separation {beta} = {alpha}{sub Zr} / {alpha}{sub Hf}. (MB)

  17. Strong influence of polymer architecture on the microstructural evolution of hafnium-alkoxide-modified silazanes upon ceramization.

    Science.gov (United States)

    Papendorf, Benjamin; Nonnenmacher, Katharina; Ionescu, Emanuel; Kleebe, Hans-Joachim; Riedel, Ralf

    2011-04-04

    The present study focuses on the synthesis and ceramization of novel hafnium-alkoxide-modified silazanes as well as on their microstructure evolution at high temperatures. The synthesis of hafnia-modified polymer-derived SiCN ceramic nanocomposites is performed via chemical modification of a polysilazane and of a cyclotrisilazane, followed by cross-linking and pyrolysis in argon atmosphere. Spectroscopic investigation (i.e., NMR, FTIR, and Raman) shows that the hafnium alkoxide reacts with the N-H groups of the cyclotrisilazane; in the case of polysilazane, reactions of N-H as well as Si-H groups with the alkoxide are observed. Consequently, scanning and transmission electron microscopy studies reveal that the ceramic nanocomposites obtained from cyclotrisilazane and polysilazane exhibited markedly different microstructures, which is a result of the different reaction pathways of the hafnium alkoxide with cyclotrisilazane and with polysilazane. Furthermore, the two prepared ceramic nanocomposites are unexpectedly found to exhibit extremely different high-temperature behavior with respect to decomposition and crystallization; this essential difference is found to be related to the different distribution of hafnium throughout the ceramic network in the two samples. Thus, the homogeneous distribution of hafnium observed in the polysilazane-derived ceramic leads to an enhanced thermal stability with respect to decomposition, whereas the local enrichment of hafnium within the matrix of the cyclotrisilazane-based sample induces a pronounced decomposition upon annealing at high temperatures. The results indicate that the chemistry and architecture of the precursor has a crucial effect on the microstructure of the resulting ceramic material and consequently on its high-temperature behavior. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1981-01-01

    High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 μm) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes 90 Zr and 180 Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer

  19. Separation of zirconium and hafnium from acompanying elements by paper chromatography in the systems of alcohol-acid

    International Nuclear Information System (INIS)

    Lebedeva, G.G.; Viktorova, M.E.

    1980-01-01

    Solvents have been chosen and investigated which provide expressed separation of zirconium and hafnium at the analysis of mineral raw materials by paper chromatography. The systems with HNO 3 and HCl containing methyl, ethyl, propyl and butyl alcohols have been studied as mobile phases for separation of zirconium and hafnium. It has been shown that alcohol contents and solvent acidity affect the Rsub(f) value of these elements. The C 2 H 5 OH-5MHCl and C 2 H 5 OH-5MHNO 3 systems are most optimal for pre-concentration of zirconium and hafnium

  20. Preparation, structure and properties of hafnium compounds in the system Hf-C-N-O

    International Nuclear Information System (INIS)

    Brundiers, G.D.

    1975-08-01

    Highly dense, homogenous and single phase hafnium carbonitride samples (with low oxygen content) were prepared in the whole concentration range of the ternary cubic carbonitrides. Stoichiometric hafnium oxicarbides were also prepared within the range of solubility. The procedure involved the hot pressing of powders of HfC, HfN, Hf, Hf-Oxide and carbon at temperatures of 3,000 0 C and pressures up to 550 kpf/cm 2 using a novel technique. Small single crystals of slightly substoichiometric HfN were also repared. The densification of the powders was studied as a function of the non-metal concentration. Carbonitrides with N/Hf ratio of 0.37 were prepared in a high temperature autoclave operating at medium pressures by the reaction of HfC with nitrogen. All the samples were characterized by density measurements, chemical, X-ray and metallographic analysis and in some cases with the aid of quantitative metallography and microprobe analysis. Typical properties investigated were lattice parameter, thermal expansion, microhardness and electrical resistivity as function of the non-metal content. For specific concentrations extreme values in the properties are attained. With the aid of the valence electron concentration (VEC) parameter, the properties can be correlated with the density of states of electrons at the Fermi level. (orig./HK) [de

  1. Low-voltage bendable pentacene thin-film transistor with stainless steel substrate and polystyrene-coated hafnium silicate dielectric.

    Science.gov (United States)

    Yun, Dong-Jin; Lee, Seunghyup; Yong, Kijung; Rhee, Shi-Woo

    2012-04-01

    The hafnium silicate and aluminum oxide high-k dielectrics were deposited on stainless steel substrate using atomic layer deposition process and octadecyltrichlorosilane (OTS) and polystyrene (PS) were treated improve crystallinity of pentacene grown on them. Besides, the effects of the pentacene deposition condition on the morphologies, crystallinities and electrical properties of pentacene were characterized. Therefore, the surface treatment condition on dielectric and pentacene deposition conditions were optimized. The pentacene grown on polystyrene coated high-k dielectric at low deposition rate and temperature (0.2-0.3 Å/s and R.T.) showed the largest grain size (0.8-1.0 μm) and highest crystallinity among pentacenes deposited various deposition conditions, and the pentacene TFT with polystyrene coated high-k dielectric showed excellent device-performance. To decrease threshold voltage of pentacene TFT, the polystyrene-thickness on high-k dielectric was controlled using different concentration of polystyrene solution. As the polystyrene-thickness on hafnium silicate decreases, the dielectric constant of polystyrene/hafnium silicate increases, while the crystallinity of pentacene grown on polystyrene/hafnium silicate did not change. Using low-thickness polystyrene coated hafnium silicate dielectric, the high-performance and low voltage operating (pentacene thin film transistor (μ: ~2 cm(2)/(V s), on/off ratio, >1 × 10(4)) and complementary inverter (DC gains, ~20) could be fabricated.

  2. Primary hafnium metal sponge and other forms, approved standard 1973

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    A specification is presented covering virgin hafnium metal commonly designated as sponge because of its porous, sponge-like texture; it may also be in other forms such as chunklets. The specification does not cover crystal bar

  3. Evolution of the hafnium isotopic composition in the RBMK reactor

    International Nuclear Information System (INIS)

    Jurkevicius, A.; Remeikis, V.

    2002-01-01

    The isotopic composition of hafnium in the radial neutron flux sensor of the RBMK-1500 reactor, the rates of the neutron absorption on Hf isotopes and the neutron spectrum in the sensor were numerically modeled. The sequence SAS2 (Shielding Analysis Sequence) program from the package SCALE 4.4A and the HELIOS code system were used for calculations. It has been obtained that the overall neutron absorption rates in hafnium for the sensors located in the 2.4 % and 2.6 % enrichment uranium-erbium nuclear fuel assemblies are by 16 % and 19 % lower than in the 2.0 % enrichment uranium nuclear fuel assemblies. The overall neutron absorption rate in hafnium decreases 2.70-2.75 times due to the sensor burnup to 5800 MW d. The sensitivity of the Hf sensors to the thermal neutron flux increases twice due to the nuclear fuel assembly burnup to 3000 MW d. The corrective factors ξ d (I) at the different integral current I of the sensors and ξ td (E) at the different burnup E of the nuclear fuel assemblies were calculated. The obtained dependence ξ d (I) calculated numerically was compared to the experimental one determined by comparing signals of the fresh sensor and the sensor with the integral current I and by processing repeated calibration results of Hf sensors in RBMK-1500 reactors. The relative relationship coefficients K T (T FA ) were found for all RBMK-1500 nuclear fuel types. (author)

  4. Preparation of hafnium metal by calciothermic reduction of HfO2

    International Nuclear Information System (INIS)

    Sharma, I.G.; Vijay, P.L.; Sehra, J.C.; Sundaram, C.V.

    1975-01-01

    Hafnium metal powder has been produced by the calciothermic reduction of hafnium oxide. The influence of various experimental parameters - such as amount of calcium in excess of stoichiometric requirement, temperature, and time of reduction - on the yield and purity of the metal has been studied. The metal powder obtained by reduction at 960 0 C (two hours) with a calcium excess of 70% analysed 600 ppm of oxygen and 147 ppm of nitrogen. A reduction efficiency of 96% has been achieved under these conditions. The refining of the powder by electron beam melting, fused salt electrolysis, and iodide process has been studied. The oxygen content in the metal could be brought down from 6900 to 148 ppm by electron beam melt-refining. (author)

  5. ENTIRELY AQUEOUS SOLUTION-GEL ROUTE FOR THE PREPARATION OF ZIRCONIUM CARBIDE, HAFNIUM CARBIDE AND THEIR TERNARY CARBIDE POWDERS

    Directory of Open Access Journals (Sweden)

    Zhang Changrui

    2016-07-01

    Full Text Available An entirely aqueous solution-gel route has been developed for the synthesis of zirconium carbide, hafnium carbide and their ternary carbide powders. Zirconium oxychloride (ZrOCl₂.8H₂O, malic acid (MA and ethylene glycol (EG were dissolved in water to form the aqueous zirconium carbide precursor. Afterwards, this aqueous precursor was gelled and transformed into zirconium carbide at a relatively low temperature (1200 °C for achieving an intimate mixing of the intermediate products. Hafnium and the ternary carbide powders were also synthesized via the same aqueous route. All the zirconium, hafnium and ternary carbide powders exhibited a particle size of ∼100 nm.

  6. On the phase formation of sputtered hafnium oxide and oxynitride films

    International Nuclear Information System (INIS)

    Sarakinos, K.; Music, D.; Mraz, S.; Baben, M. to; Jiang, K.; Nahif, F.; Braun, A.; Zilkens, C.; Schneider, J. M.; Konstantinidis, S.; Renaux, F.; Cossement, D.; Munnik, F.

    2010-01-01

    Hafnium oxynitride films are deposited from a Hf target employing direct current magnetron sputtering in an Ar-O 2 -N 2 atmosphere. It is shown that the presence of N 2 allows for the stabilization of the transition zone between the metallic and the compound sputtering mode enabling deposition of films at well defined conditions of target coverage by varying the O 2 partial pressure. Plasma analysis reveals that this experimental strategy facilitates control over the flux of the O - ions which are generated on the oxidized target surface and accelerated by the negative target potential toward the growing film. An arrangement that enables film growth without O - ion bombardment is also implemented. Moreover, stabilization of the transition sputtering zone and control of the O - ion flux without N 2 addition is achieved employing high power pulsed magnetron sputtering. Structural characterization of the deposited films unambiguously proves that the phase formation of hafnium oxide and hafnium oxynitride films with the crystal structure of HfO 2 is independent from the O - bombardment conditions. Experimental and theoretical data indicate that the presence of vacancies and/or the substitution of O by N atoms in the nonmetal sublattice favor the formation of the cubic and/or the tetragonal HfO 2 crystal structure at the expense of the monoclinic HfO 2 one.

  7. Solvent extraction of titanium(IV), zirconium(IV) and hafnium(IV) salicylates using liquid ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Sundaramurthi, N M; Shinde, V M

    1989-02-01

    A solvent extraction method is proposed for the extraction of quadrivalent titanium, zirconium an hafnium from salicylate media using liquid ion exchangers such as Aliquat 336 and trioctylamine dissolved in xylene. The optimum conditions were evaluated from a critical study of the following: pH, salicylate concentration, amine concentration, diluent and period of equilibration. The method allows the separation of titanium, zirconium and hafnium from binary mixtures containing commonly associated metal ions and is applicable to the analysis of real samples such as BCS-CRM 387 nimonic 901, BCS-CRM 243/4 ferro-titanium, BCS-CRM 307 magnesium alloy and BCS-CRM 388 zircon. Titanium is determined either with hydrogen peroxide or by atomic absorption spectrometry whereas zirconium and hafnium are determined spectrophotometrically with Alizarin Red S and Zylenol Orange, respectively. The results of both separation and analysis are reported. The method is precise, accurate and fast.

  8. Solvent extraction of zirconium and hafnium using MIBK-HSCN-HCL process

    International Nuclear Information System (INIS)

    Borges, J.A.L.; Cunha, O.G.C. da

    1985-01-01

    The separation process of zirconium and hafnium, using MIBK as extractant in a set of mixer-settler is described. The chemical analysis was done by X-ray fluorescence and emission spectrography. (Author) [pt

  9. Radiation effects on the electrical properties of hafnium oxide based MOS capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Petrosky, J. C. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH); McClory, J. W. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH); Bielejec, Edward Salvador; Foster, J. C. (Air Force Institute of Technology, Wright-Patterson Air Force Base, OH)

    2010-10-01

    Hafnium oxide-based MOS capacitors were investigated to determine electrical property response to radiation environments. In situ capacitance versus voltage measurements were analyzed to identify voltage shifting as a result of changes to trapped charge with increasing dose of gamma, neutron, and ion radiation. In situ measurements required investigation and optimization of capacitor fabrication to include dicing, cleaning, metalization, packaging, and wire bonding. A top metal contact of 200 angstroms of titanium followed by 2800 angstroms of gold allowed for repeatable wire bonding and proper electrical response. Gamma and ion irradiations of atomic layer deposited hafnium oxide on silicon devices both resulted in a midgap voltage shift of no more than 0.2 V toward less positive voltages. This shift indicates recombination of radiation induced positive charge with negative trapped charge in the bulk oxide. Silicon ion irradiation caused interface effects in addition to oxide trap effects that resulted in a flatband voltage shift of approximately 0.6 V also toward less positive voltages. Additionally, no bias dependent voltage shifts with gamma irradiation and strong oxide capacitance room temperature annealing after ion irradiation was observed. These characteristics, in addition to the small voltage shifts observed, demonstrate the radiation hardness of hafnium oxide and its applicability for use in space systems.

  10. Investigation of chlorination of zirconium and hafnium and their compounds in discharge from hollow cathode

    International Nuclear Information System (INIS)

    Ioffe, R.B.; Korovin, Yu.I.

    1978-01-01

    The possibility is investigated of chlorinating various zirconium and hafnium compounds (metal, oxide, carbide) in a hot discharge from a hollow cathode with various chlorinating reagents: copper monochloride, nickel chloride, magnesium chloride, for the purpose of accelerating their entrance into the excitation zone. It has been shown thermodynamically and experimentally that chlorination of metal zirconium and hafnium and their carbides with copper monochloride in hot hollow cathode conditions provides a sharp increase in the intensity of the lines of these elements

  11. Development and characterization of ultrathin hafnium titanates as high permittivity gate insulators

    Science.gov (United States)

    Li, Min

    High permittivity or high-kappa materials are being developed for use as gate insulators for future ultrascaled metal oxide semiconductor field effect transistors (MOSFETs). Hafnium containing compounds are the leading candidates. Due to its moderate permittivity, however, it is difficult to achieve HfO2 gate structures with an EOT well below 1.0 nm. One approach to increase HfO2 permittivity is combining it with a very high-kappa material, such as TiO2. In this thesis, we systematically studied the electrical and physical characteristics of high-kappa hafnium titanates films as gate insulators. A series of HfxTi1-xO2 films with well-controlled composition were deposited using an MOCVD system. The physical properties of the films were analyzed using a variety of characterization techniques. X-ray micro diffraction indicates that the Ti-rich thin film is more immune to crystallization. TEM analysis showed that the thick stoichiometric HfTiO 4 film has an orthorhombic structure and large anisotropic grains. The C-V curves from the devices with the hafnium titanates films displayed relatively low hysteresis. In a certain composition range, the interfacial layer (IL) EOT and permittivity of HfxTi1-x O2 increases linearly with increasing Ti. The charge is negative for HfxTi1-xO2/IL and positive for Si/IL interface, and the magnitude increases as Hf increases. For ultra-thin films (less than 2 nm EOT), the leakage current increases with increasing HE Moreover, the Hf-rich sample has weaker temperature dependence of the current. In the MOSFET devices with the hafnium titanates films, normal transistor characteristics were observed, also electron mobility degradation. Next, we investigated the effects that different pre-deposition surface treatments, including HF dipping, NH3 surface nitridation, and HfO2 deposition, have on the electrical properties of hafnium titanates. Surface nitridation shows stronger effect than the thin HfO2 layer. The nitrided samples displayed a

  12. Separation of zirconium and hafnium using paper distribution chromatography

    International Nuclear Information System (INIS)

    Lebedeva, G.G.; Viktorova, M.E.

    1981-01-01

    A method is suggested of chromatographic separation of zirconium and hafnium in a CCl 4 -tributyl phosphate system (1:9) containing KCl as a salting-out agent in 5 M HNO 3 at 28-30 deg C. Zr and Hf are deterfmined in articiial mixtures under optimal chromatography conditions using visual colorimetry [ru

  13. Hafnium as a prospective absorber for VVER-1000 reactors of Ukraine

    International Nuclear Information System (INIS)

    Afanas'ev, A.A.; Konotop, Yu.F.; Odejchuk, N.L.

    2000-01-01

    Nuclear-physical parameters of hafnium having in mind its use as an absorber, are considered. Technical aspects of Hf production are exposed. Use of B 4 C/Hf absorber is twice cheaper than a standard one

  14. Evaluation of thermodynamic data on zirconium and hafnium halides and oxyhalides by means of transport experiments

    International Nuclear Information System (INIS)

    Dittmer, G.; Niemann, U.

    1987-01-01

    A consistent set of thermodynamic data for zirconium and hafnium halides, oxides and oxyhalides was achieved. It was found that formation enthalpies of gaseous compounds could be derived from solubility measurements together with theoretical estimations and a revision of literature data. Free energy functions were calculated employing statistical mechanics. Data for liquid and solid compounds were obtained via sublimation and vaporization data. Chemical equilibria of zirconium and hafnium with halogens are discussed. 51 refs.; 16 figs.; 14 tabs

  15. Electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium

    International Nuclear Information System (INIS)

    Serrano, K.

    1998-01-01

    The aim of this work is to study the electrodeposition in molten salts of metals used in nuclear industry: hafnium and uranium. The experiment is carried out in a molten alkaline halogenide medium in a temperature range between 670 and 750 degrees Celsius. The first part of this work concerns more particularly the electrochemical behaviour of the hafnium and uranium ions in the electrolytic solution. The reduction mechanisms of these ions have been studied by the use of three methods: cyclic voltametry, chrono-potentiometry and square wave voltametry. Results have shown that the process of metal deposition is difficult to explain because secondary reactions (as for instance: adsorption phenomena or cathodic deposit dissolution) occur. The uranium germination has then been studied by modelling of chrono-amperograms. The experiments have shown that the deposition is the result of the initial uranium crystal growth and depends on the electrolyte diffusion. The second part of this work deals with the implementation of hafnium and uranium deposition taking into account the preceding mechanistic studies. Depositions have all been observed by physical methods as for instance scanning electron microscopy. Particular experimental solutions (soluble anode, addition of fluoride ions to the electrolyte) have been used. The obtained deposition of hafnium is smooth and adheres very well to the substrate. The uranium depositions have been implemented with the use of a soluble anode. Uranium is deposited in a dendritic shape to the cathode. It has also been shown that the electro-kinetic parameters (temperature, uranium ions concentration, current density) have not an important influence on the dendritic morphology of the deposition. This morphology could be the consequence of particular convection movements to the surface of the cathode. (O.M.)

  16. Synthesis and characterization of Ho3+ doped hafnium oxide TLD for radiation dosimeter

    International Nuclear Information System (INIS)

    Sekar, Nandakumar; Ganesan, Bharanidharan; Sahib, Hajee Reyaz Ali; Aruna, Prakasarao; Ganesan, Singaravelu; Thamilkumar, P.; Rai, R.R.

    2017-01-01

    Cancer is a dreaded disease which is treated by Radiotherapy, Chemotherapy and Surgery. Radiotherapy plays a vital role in treatment of cancer and recently measurements of invivo radiation dosimetric in patient is of great interest due to high dose gradients in advanced technology like IMRT, IGRT etc. Hence, for the last few decades, a great degree of interest has been shown for the hafnium oxide for radiation dosimetric applications, due to its high dielectric constant, wide band gap and better interface properties such as chemical stability, conduction band offset and thermodynamic stability. In the present study, Synthesis and characterization of Ho 3+ doped Hafnium oxide were carried out and its applications towards radiation dosimeter were investigated

  17. Use of hafnium in control bars of nuclear reactors; Uso de hafnio en barras de control de reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J.R.; Alonso V, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: jrrs@nuclear.inin-mx

    2003-07-01

    Recently the use of hafnium as neutron absorber material in nuclear reactors has been reason of investigation by virtue of that this material has nuclear properties as to the neutrons absorption and structural that can prolong the useful life of the control mechanisms of the nuclear reactors. In this work some of those more significant hafnium properties are presented like nuclear material. Also there are presented calculations carried out with the HELIOS code for fuel cells of uranium oxide and of uranium and plutonium mixed oxides under controlled conditions with conventional bars of boron carbide and also with similar bars to which are substituted the absorbent material by metallic hafnium, the results are presented in this work. (Author)

  18. Plasma spraying of zirconium carbide – hafnium carbide – tungsten cermets

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Ctibor, Pavel; Cheong, D.-I.; Yang, S.-H.

    2009-01-01

    Roč. 9, č. 1 (2009), s. 49-64 ISSN 1335-8987 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma spraying * cermet coatings * microhardness * zirconium carbide * hafnium carbide * tungsten * water stabilized plasma Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  19. Extraction of zirconium and hafnium thiocyanates by CH3COCH2CH.(CH3)2-HSCN solvent from chloride medium

    International Nuclear Information System (INIS)

    Okada, A.T.

    1982-01-01

    A zirconium-hafnium separation process for application in nuclear industry is presented. The extraction of zirconium and hafnium thiocyanates in chloride medium by hexone-HSCN solvent was studied. The extraction process was developed, varying the parameters, such as, concentrations of the metals, the thiocyanate ion, the sulphate ion and free acidity in aqueous phase. (Author) [pt

  20. Pyroelectricity of silicon-doped hafnium oxide thin films

    Science.gov (United States)

    Jachalke, Sven; Schenk, Tony; Park, Min Hyuk; Schroeder, Uwe; Mikolajick, Thomas; Stöcker, Hartmut; Mehner, Erik; Meyer, Dirk C.

    2018-04-01

    Ferroelectricity in hafnium oxide thin films is known to be induced by various doping elements and in solid-solution with zirconia. While a wealth of studies is focused on their basic ferroelectric properties and memory applications, thorough studies of the related pyroelectric properties and their application potential are only rarely found. This work investigates the impact of Si doping on the phase composition and ferro- as well as pyroelectric properties of thin film capacitors. Dynamic hysteresis measurements and the field-free Sharp-Garn method were used to correlate the reported orthorhombic phase fractions with the remanent polarization and pyroelectric coefficient. Maximum values of 8.21 µC cm-2 and -46.2 µC K-1 m-2 for remanent polarization and pyroelectric coefficient were found for a Si content of 2.0 at%, respectively. Moreover, temperature-dependent measurements reveal nearly constant values for the pyroelectric coefficient and remanent polarization over the temperature range of 0 ° C to 170 ° C , which make the material a promising candidate for IR sensor and energy conversion applications beyond the commonly discussed use in memory applications.

  1. Separation process of zirconium and hafnium

    International Nuclear Information System (INIS)

    Hure, J.; Saint-James, R.

    1955-01-01

    About the separation different processes of zirconium-hafnium, the extraction by solvent in cross-current is the most easily the process usable on an industrial scale. It uses tributyl phosphate as solvent, diluted with white spirit to facilitate the decanting. Some exploratory tests showed that nitric environment seemed the most favorable for extraction; but a lot of other factors intervene in the separation process. We studied the influence of the acidity successively, the NO 3 - ions concentration, the role of the cation coming with NO 3 - , as well as the influence of the concentration of zirconium in the solution on the separation coefficient β = α Zr / α Hf . (M.B.) [fr

  2. Synthesis and characterization of hafnium oxide films for thermo and photoluminescence applications

    International Nuclear Information System (INIS)

    Guzman Mendoza, J.; Aguilar Frutis, M.A.; Flores, G. Alarcon; Garcia Hipolito, M.; Maciel Cerda, A.; Azorin Nieto, J.; Rivera Montalvo, T.; Falcony, C.

    2010-01-01

    Hafnium oxide (HfO 2 ) films were deposited by the ultrasonic spray pyrolysis process. The films were synthesized from hafnium chloride as raw material in deionized water as solvent and were deposited on corning glass substrates at temperatures from 300 to 600 deg. C. For substrate temperatures lower than 400 deg. C the deposited films were amorphous, while for substrate temperatures higher than 450 deg. C, the monoclinic phase of HfO 2 appeared. Scanning electron microscopy showed that the film's surface resulted rough with semi-spherical promontories. The films showed a chemical composition close to HfO 2 , with an Hf/O ratio of about 0.5. UV radiation was used in order to achieve the thermoluminescent characterization of the films; the 240 nm wavelength induced the best response. In addition, preliminary photoluminescence spectra, as a function of the deposition temperatures, are shown.

  3. A study of a production process for hafnium-free zirconium from zircon

    International Nuclear Information System (INIS)

    Ratanalert, N.

    1985-01-01

    The purpose of this experiment was to extract and purify the zirconium from zircon. The effects of time of extraction and stripping of zirconium, concentration of feed solution, concentration of hydrochloric acid in stripping process, equilibrium curve of extraction of zirconium and hafnium and equilibrium curve of stripping zirconium or scrubbing hafnium were studied from standard zirconium and hafnium. The results, subsequently were applied to the extraction procedures for zirconium from zircon. Minus 100 mesh zircon was fused with sodium hydroxide in the ratio of 1 : 6 at 700 degree C for l hour. After fusion the zirconate was leached with water and dissolved in hot concentrated hydrochloric acid. Zirconyl chloride octahydrate crystallized out when the solution was cooled. An agueons solution of zirconyl chloride was used as the feed to the hexone - thiocyanate solvent extraction process. This was prepared by dissolving zirconyl chloride octahydrate crystal in waster. This zirconium feed solution in 1 M HCl and 1 M N H 4 CNS was extracted with 2.7 m N H 4 CNS in hexone and then stripped with 3.6 M HCl the aqueous phase was got rid of thiocyanate ion by extracting with pure hexone, then the zirconium in aqueous phase was precipitated with sulfuric acid and ammonium hydroxide at pH 1.8 - 2.0 and zirconium oxide was obtained by ignition at 700 degree C. The process could be modified to improve the purity of zirconium by using cation exchange resin to get rid of thiocyanate ion after solvent extraction process

  4. Vapor pressure, heat capacities, and phase transitions of tetrakis(tert-butoxy)hafnium

    Czech Academy of Sciences Publication Activity Database

    Fulem, Michal; Růžička, K.

    2011-01-01

    Roč. 311, Dec. (2011), s. 25-29 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : tetrakis(tert-butoxy)hafnium * MO precursor * vapor pressure * heat capacity * vaporization enthalpy * enthalpy of fusion Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

  5. Pentamethylcyclopentadienyl Zirconium and Hafnium Polyhydride Complexes : Synthesis, Structure, and Reactivity

    NARCIS (Netherlands)

    Visser, Cindy; Hende, Johannes R. van den; Meetsma, Auke; Hessen, Bart; Teuben, Jan H.

    2001-01-01

    The half-sandwich zirconium and hafnium N,N-dimethylaminopropyl complexes Cp*M[(CH2)3NMe2]Cl2 (Cp* = η5-C5Me5, M = Zr, 1; Hf, 2) and Cp*M[(CH2)3NMe2]2Cl (M = Zr, 3; Hf, 4) were synthesized by mono- or dialkylation of Cp*MCl3 with the corresponding alkyllithium and Grignard reagents. Hydrogenolysis

  6. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  7. Ion-bombardment-induced reduction in vacancies and its enhanced effect on conductivity and reflectivity in hafnium nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhiqing; Wang, Jiafu; Hu, Chaoquan; Zhang, Xiaobo; Dang, Jianchen; Gao, Jing; Zheng, Weitao [Jilin University, School of Materials Science and Engineering, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Changchun (China); Zhang, Sam [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Xiaoyi [Chinese Academy of Sciences, Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun (China); Chen, Hong [Jilin University, Department of Control Science and Engineering, Changchun (China)

    2016-08-15

    Although the role of ion bombardment on electrical conductivity and optical reflectivity of transition metal nitrides films was reported previously, the results were controversial and the mechanism was not yet well explored. Here, we show that proper ion bombardment, induced by applying the negative bias voltage (V{sub b}), significantly improves the electrical conductivity and optical reflectivity in rocksalt hafnium nitride films regardless of level of stoichiometry (i.e., in both near-stoichiometric HfN{sub 1.04} and over-stoichiometric HfN{sub 1.17} films). The observed improvement arises from the increase in the concentration of free electrons and the relaxation time as a result of reduction in nitrogen and hafnium vacancies in the films. Furthermore, HfN{sub 1.17} films have always much lower electrical conductivity and infrared reflectance than HfN{sub 1.04} films for a given V{sub b}, owing to more hafnium vacancies because of larger composition deviation from HfN exact stoichiometry (N:Hf = 1:1). These new insights are supported by good agreement between experimental results and theoretical calculations. (orig.)

  8. Results for heterogeneous poisoning of the critical HTR-test facility KAHTER using absorber elements containing hafnium and boron

    International Nuclear Information System (INIS)

    Drueke, V.; Filges, D.; Nabi, R.; Neef, R.D.; Paul, N.; Schaal, H.

    1979-10-01

    Experiments and checking computations for investigating the initial-core poisoning of the pebble bed high temperature reactor are described. Following the example of the THTR-300, THTR absorber elements poisoned with hafnium/boron were added to the THTR fuel- and graphite elements of the KAHTER core. Three different hafnium-boron poisoned core loadings, corresponding to 2.7, 5.3 and 8% reactivity compensation, were used in the experiments. For purposes of comparison, two cores exclusively boron poisoned were also studied. The poisoning of these cores correspond to 2.7 and 8% reactivity compensation. The experiments and checking computations should serve to test the accuracy of the theoretical models and data sets in modeling the reactivity effects of absorber poisoned elements in the THTR. In particular, the applicability of the nuclear data of hafnium and the treatment of resonance calculations should be verified. In addition, to determining critical masses and ksub(eff), special emphasis was placed in the experiments on the exact determination of all reactivity effects. In some cases, repeated loading of a configuration also provided a measure of the reproducibility of ksub(eff). The experiments were checked computationally using the GAMTEREX code package and the program system RSYST. These two computation packages contain different data bases, - although the hafnium data are identical -, and the computing models differ in certain phases of the calculations. Both code systems compute ksub(eff) values to within the present accuracy requirements, whereas the program system RSYST gives better agreement with experimental measurements. (orig.) 891 RW/orig. 892 RDG [de

  9. Calculation of correlation between spins in a magnetic substance; Calcul des correlations entre spins dans une substance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Gennes, P.G. de [Commissariat a l' Energie Atomique, Saclay (France)

    1959-07-01

    The report states an elementary calculation of the correlation between spins in a magnetic substance, and particularly of their asymptotic form with regard to relatively wide-spaced spins. This permits the determination of the phenomenological parameters introduced by Var Hove to describe the magnetic scatter of neutrons in the critical opalescent area. (author) [French] On donne un calcul elementaire des correlations entre spins dans une substance magnetique, et notamment de leur forme asymptotique pour des spins assez eloignes. Ceci permet de determiner les parametres phenomenologiques introduits par Van Hove pour decrire la diffusion magnetique des neutrons dans la region d'opalescence critique. (auteur)

  10. Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

    Science.gov (United States)

    Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

    2017-07-01

    In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

  11. Rare-earth hafnium oxide materials for magnetohydrodynamic (MHD) generator application

    Energy Technology Data Exchange (ETDEWEB)

    Marchant, D. D; Bates, J. L.

    1979-01-01

    Several ceramic materials based on rare-earth hafnium oxides have been identified as potential high-temperature electrodes and low-temperature current leadouts for open cycle coal-fired MHD generator channels. The electrode-current leadouts combination must operate at temperatures between 400 and 2000K with an electrical conductivity greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/. The electrodes will be exposed to flowing (linear flow rates up to 100 m/s) potassium seeded coal combustion gases (plasma core temperatures between 2400 to 3200/sup 0/K) and coal slag. During operation the electrodes must conduct direct electric current at densities near 1.5 amp/cm/sup 2/. Consequently, the electrodes must be resistant to electrochemical decompositions and interactions with both the coal slag and potassium salts (e.g., K/sub 2/SO/sub 4/, K/sub 2/CO/sub 3/). The current leadout materials are placed between the hot electrodes and the water-cooled copper structural members and must have electrical conductivities greater than 10/sup -2/ ohm/sup -1/ cm/sup -1/ between 1400 and 400/sup 0/K. The current leadouts must be thermally and electrochemically compatible with the electrode, copper, and potassium salts. Ideally, the electrodes and current leadouts should exhibit minimal ionic conductivity. The fabrication, electrical conductivity, and electrochemical corrosion of rare-earth hafnium oxide materials are discussed. (WHK)

  12. Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago.

    Science.gov (United States)

    Næraa, T; Scherstén, A; Rosing, M T; Kemp, A I S; Hoffmann, J E; Kokfelt, T F; Whitehouse, M J

    2012-05-30

    Earth's lithosphere probably experienced an evolution towards the modern plate tectonic regime, owing to secular changes in mantle temperature. Radiogenic isotope variations are interpreted as evidence for the declining rates of continental crustal growth over time, with some estimates suggesting that over 70% of the present continental crustal reservoir was extracted by the end of the Archaean eon. Patterns of crustal growth and reworking in rocks younger than three billion years (Gyr) are thought to reflect the assembly and break-up of supercontinents by Wilson cycle processes and mark an important change in lithosphere dynamics. In southern West Greenland numerous studies have, however, argued for subduction settings and crust growth by arc accretion back to 3.8 Gyr ago, suggesting that modern-day tectonic regimes operated during the formation of the earliest crustal rock record. Here we report in situ uranium-lead, hafnium and oxygen isotope data from zircons of basement rocks in southern West Greenland across the critical time period during which modern-like tectonic regimes could have initiated. Our data show pronounced differences in the hafnium isotope-time patterns across this interval, requiring changes in the characteristics of the magmatic protolith. The observations suggest that 3.9-3.5-Gyr-old rocks differentiated from a >3.9-Gyr-old source reservoir with a chondritic to slightly depleted hafnium isotope composition. In contrast, rocks formed after 3.2 Gyr ago register the first additions of juvenile depleted material (that is, new mantle-derived crust) since 3.9 Gyr ago, and are characterized by striking shifts in hafnium isotope ratios similar to those shown by Phanerozoic subduction-related orogens. These data suggest a transitional period 3.5-3.2 Gyr ago from an ancient (3.9-3.5 Gyr old) crustal evolutionary regime unlike that of modern plate tectonics to a geodynamic setting after 3.2 Gyr ago that involved juvenile crust generation by plate

  13. The interaction of fast neutrons with hafnium

    International Nuclear Information System (INIS)

    Smith, A.B.

    2002-01-01

    Elemental hafnium neutron total cross sections are measured from ∼0.75 to 4.5 MeV in steps of ∼40 keV. Differential neutron elastic-scattering cross sections are measured from ∼4.5 to 10.0 MeV in ∼0.5 MeV steps and at 40 scattering angles distributed between ∼17 and 160 deg. These data are combined with those found in the literature to construct a comprehensive experimental data base which is interpreted in terms of coupled-channels models. Physical characteristics of the resulting potentials are discussed. Comparisons are made with ENDF/B-6 (MAT 7200). A detailed report of this work is given by Smith (Smith, A., 2001. Argonne National Laboratory Report ANL/NDM-153)

  14. Reinforcement against crack propagation of PWR absorbers by development of boron-carbon-hafnium composites

    International Nuclear Information System (INIS)

    Provot, B.; Herter, P.

    2000-01-01

    In order to improve the mechanical behaviour of materials used as neutron absorbers in nuclear reactors, we have developed CERCER or CERMET composites with boron and hafnium. Thus a new composite B 4 C/HfB 2 has been especially studied. We have identified three kinds of degradation under irradiation (thermal gradient, swelling due to fission products and accidental corrosion) that induce imposed deformations cracking phenomena. Mechanical behaviour and crack propagation resistance have been studied by ball-on-three-balls and double torsion tests. A special device was developed to enable crack propagation and associated stress intensity factor measurements. Effects of structure and of a second phase are underline. First results show that these materials present crack initiation and propagation resistance much higher than pure boron carbide or hafnium diboride. We observe R-Curves effects, crack bridging or branching, crack arrests, and toughness increases that we can relate respectively to the composite structures. (author)

  15. Titrimetric determination of thiocyanate in solutions of the hafnium-zirconium separation process

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Botbol, Moises; Hernandez, M.H.

    1980-01-01

    The control of the thiocyanate concentration is necessary during the process of separating hafnium from zirconium by the hexone-thiocyanate method. Said control is carried out by titrimetric determination of thiocyanate in aqueous and organic solutions containing hydrochloric acid and ammonium thiocyanate in presence or absence of zirconium and/or hafnium. The method consists in a redox volumetric analysis using a cerium (IV) salt as titrating agent, and ferroine as the final point indicator. Owing to the instability of thiocyanate in an acid medium it is necessary to know previously if the decomposition of solutions with different concentration of ammonium thiocyanate and hydrochloric acid may have an influence upon the analytic results or may even invalidate them. In order to obtain reliable results, it must be taken into account that the stability of the solutions depends on the thiocyanate concentration, the acidity and the time elapsed from the moment the sample is taken until the test is performed. The decomposition process can be slowed down by cooling the solutions. This method allows to control the plant and does not require any special equipment. (M.E.L) [es

  16. Synthesis and characterization of hafnium oxide for luminescent applications

    International Nuclear Information System (INIS)

    Guzman Mendoza, J.; Aguilar Frutis, M.A.; Flores, G. Alarcon; Garcia Hipolito, M.; Azorin Nieto, J.; Rivera Montalvo, T.; Falcony, C.

    2008-01-01

    Full text: Hafnium oxide (HfO 2 ) is a material with a wide range of possible technological applications because it's chemical and physical properties such as high melting point, high chemical stability, high refraction index, high dielectric constant and hardness near to diamond in the tetragonal phase. The large energy gap and low phonon frequencies of the HfO 2 makes it appropriate as a host matrix for been doped with rare earth activators. Efficient luminescent materials find wide application in electroluminescent flat panel displays; color plasma displays panels, scintillators, cathode ray tubes, fluorescent lamps, lasers, etc. In recent years the study of luminescent materials based on HfO 2 has been intensified. Some groups have studied the optical properties of doped and undoped HfO 2 . In this contribution, Hafnium Oxide (HfO 2 ) films were prepared using the spray pyrolysis deposition technique. The material was synthesized using chlorides as raw materials in deionised water as solvent and deposited on Corning glass substrates at temperatures from 300 deg C to 600 deg C. For substrate temperatures lower than 400 deg C, the deposited films are amorphous, while for substrate temperatures higher than 450 deg C, the monoclinic phase of HfO 2 appears. Scanning electron microscopy with microprobe analysis was use to observe the microstructure and obtain the chemical composition of the films; rough surfaces with spherical particles were appreciated. UV and low energy X Ray radiations were used in order to achieve the thermoluminescent characterization of the films as a function of the deposition temperature

  17. Titanium, zirconium- and hafnium containing initiators in the polymerization of acrylic monomers to ''living'' polymers

    International Nuclear Information System (INIS)

    Farnham, W.B.; Hertler, W.R.

    1988-01-01

    This patent describes a process for preparing ''living'' polymer. The process comprises contacting one or more acrylic monomers under polymerizing conditions with a polymerization-initiating amount of a tetra-coordinate organotitanium, organozirconium or organo-hafnium polymerization initiator, and ''living'' polymers produced thereby

  18. Zirconium and hafnium tetrachloride separation by extractive distillation with molten zinc chloride lead chloride solvent

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1988-01-01

    In an extractive distillation method for separating hafniuim tetrachloride from zirconium tetrachloride of the type wherein a mixture of zirconium and hafnium tetrachlorides is introduced into an extractive distillation column, which extractive distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a molten salt solvent is circulated into the reflux condenser and through the column to provide a liquid phase, and wherein molten salt solvent containing zirconium tetrachloride is taken from the reboiler and run through a stripper to remove zirconium tetrachloride product from the molten salt solvent and the stripped molten salt solvent is returned to the reflux condenser and hafnium tetrachloride enriched vapor is taken as product from the reflux condenser, the improvement is described comprising: the molten salt having a composition of at least 30 mole percent zinc chloride and at least 10 mole percent of lead chloride

  19. Atomic layer deposition of calcium oxide and calcium hafnium oxide films using calcium cyclopentadienyl precursor

    International Nuclear Information System (INIS)

    Kukli, Kaupo; Ritala, Mikko; Sajavaara, Timo; Haenninen, Timo; Leskelae, Markku

    2006-01-01

    Calcium oxide and calcium hafnium oxide thin films were grown by atomic layer deposition on borosilicate glass and silicon substrates in the temperature range of 205-300 o C. The calcium oxide films were grown from novel calcium cyclopentadienyl precursor and water. Calcium oxide films possessed refractive index 1.75-1.80. Calcium oxide films grown without Al 2 O 3 capping layer occurred hygroscopic and converted to Ca(OH) 2 after exposure to air. As-deposited CaO films were (200)-oriented. CaO covered with Al 2 O 3 capping layers contained relatively low amounts of hydrogen and re-oriented into (111) direction upon annealing at 900 o C. In order to examine the application of CaO in high-permittivity dielectric layers, mixtures of Ca and Hf oxides were grown by alternate CaO and HfO 2 growth cycles at 230 and 300 o C. HfCl 4 was used as a hafnium precursor. When grown at 230 o C, the films were amorphous with equal amounts of Ca and Hf constituents (15 at.%). These films crystallized upon annealing at 750 o C, showing X-ray diffraction peaks characteristic of hafnium-rich phases such as Ca 2 Hf 7 O 16 or Ca 6 Hf 19 O 44 . At 300 o C, the relative Ca content remained below 8 at.%. The crystallized phase well matched with rhombohedral Ca 2 Hf 7 O 16 . The dielectric films grown on Si(100) substrates possessed effective permittivity values in the range of 12.8-14.2

  20. Correlações entre as estruturas dos membros inferiores Correlations between lower limb structures

    Directory of Open Access Journals (Sweden)

    Francis Trombini-Souza

    2009-09-01

    Full Text Available A literatura sugere que mudanças no ângulo Q podem alterar o arco plantar longitudinal e que um mau alinhamento do retropé poderia também modificar a postura do antepé. Contudo, não foram encontrados estudos que correlacionem quantitativamente, na postura ortostática bipodal, todos esses segmentos. Assim, o propósito deste estudo foi avaliar quantitativamente e verificar eventuais correlações entre o ângulo Q, arco plantar longitudinal, alinhamento frontal do tendão do calcâneo e antepé, na postura ortostática bipodal, por meio de fotogrametria. Foram avaliados 30 indivíduos jovens (60 membros inferiores de ambos os sexos, com idade entre 18 e 24 anos. Foi feita captura fotográfica digital no plano frontal anterior de joelho e antepé; no plano frontal posterior, do tendão do calcâneo; e da impressão plantar exposta no podoscópio. Os dados foram analisados estatisticamente e o nível de signficância fixado em 5%. Foram obtidas as seguintes correlações entre: ângulo Q X arco plantar, r=0,29 (p=0,021; ângulo Q X antepé, r=0,23 (p=0,092; ângulo Q X tendão do calcâneo, r=0,06 (p=0,627; arco plantar X antepé, r=0,09 (p=0,464; arco plantar X tendão do calcâneo, r=-0,05 (p=0,680; e antepé X tendão do calcâneo, r=-0,02 (p=0,857. A única correlação significativa encontrada, embora fraca, foi entre o ângulo Q e o arco plantar longitudinal medial, o que sugere cautela ao se inferirem correlações entre estruturas dos membros inferiores.Literature often reports that changes in the Q angle may alter the longitudinal plantar arch and that a misalignment of the rearfoot might also modify forefoot position. However, no studies could be found that quantitatively establish correlations between those lower limb segments in orthostatic bipedal posture. The goal of this study was to quantitatively assess possible correlations between the Q angle, longitudinal plantar arch, frontal forefoot and rearfoot alignment in bipedal

  1. Separation of zirconium--hafnium by nitride precipitation

    International Nuclear Information System (INIS)

    Anderson, R.N.; Parlee, N.A.

    1977-01-01

    A method is described for the separation of a light reactive metal (e.g., zirconium) from a heavy reactive metal (e.g., hafnium) by forming insoluble nitrides of the metals in a molten metal solvent (e.g., copper) inert to nitrogen and having a suitable density for the light metal nitride to form a separate phase in the upper portion of the solvent and for the heavy metal nitride to form a separate phase in the lower portion of the solvent. Nitriding is performed by maintaining a nitrogen-containing atmosphere over the bath. The light and heavy metals may be an oxide mixture and carbothermically reduced to metal form in the same bath used for nitriding. The nitrides are then separately removed and decomposed to form the desired separate metals. 16 claims, 1 figure

  2. Modified method for zirconium or hafnium gravimetric determination with glycolic acid derivatives

    International Nuclear Information System (INIS)

    Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Neto, A.

    1989-01-01

    The conditions for gravimetric determination of zirconium or hafnium by glicolic acid derivatives were studied by thermogravimetric analysis. The method utilized shown that after precipitation, washing and drying of precipitates at 150 0 C, the resulting solid was weighed in the form of [M{RCH(OH)COO} 4 ] (M = Zr,Hf;R = C 6 H 5 , β-C 10 H 7 ,p-BrC 6 H 4 ). (author) [pt

  3. On-line separation of refractory hafnium and tantalum isotopes at the ISOCELE separator

    CERN Document Server

    Liang, C F; Obert, J; Paris, P; Putaux, J C

    1981-01-01

    By chemical evaporation technique, neutron deficient hafnium nuclei have been on-line separated at the ISOCELE facility, from the isobar rare-earth elements, in the metal-fluoride HfF/sub 3//sup +/ ion form. Half-lives of /sup 162-165/Hf have been measured. Similarly, tantalum has been selectively separated on the TaF/sub 4//sup +/ form. (4 refs) .

  4. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide.

    Science.gov (United States)

    Timm, Rainer; Head, Ashley R; Yngman, Sofie; Knutsson, Johan V; Hjort, Martin; McKibbin, Sarah R; Troian, Andrea; Persson, Olof; Urpelainen, Samuli; Knudsen, Jan; Schnadt, Joachim; Mikkelsen, Anders

    2018-04-12

    Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor-oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor-oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

  5. Ground-state structures of Hafnium clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)

    2015-04-24

    Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.

  6. Near net shape processing of zirconium or hafnium metals and alloys

    International Nuclear Information System (INIS)

    Evans, S.C.

    1992-01-01

    This patent describes a process for producing a metal shape. It comprises: plasma arc melting a metal selected from zirconium, hafnium and alloys thereof comprising at least about 90 w/o of these metals to form a liquid pool; pouring the metal form the pool into a mold to form a near net shape; and reducing the metal from its near net shape to a final size while maintaining the metal temperature below the alpha-beta transition temperature throughout the size reducing step

  7. In-Pile Experiment of a New Hafnium Aluminide Composite Material to Enable Fast Neutron Testing in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Donna Post Guillen; Douglas L. Porter; James R. Parry; Heng Ban

    2010-06-01

    A new hafnium aluminide composite material is being developed as a key component in a Boosted Fast Flux Loop (BFFL) system designed to provide fast neutron flux test capability in the Advanced Test Reactor. An absorber block comprised of hafnium aluminide (Al3Hf) particles (~23% by volume) dispersed in an aluminum matrix can absorb thermal neutrons and transfer heat from the experiment to pressurized water cooling channels. However, the thermophysical properties, such as thermal conductivity, of this material and the effect of irradiation are not known. This paper describes the design of an in-pile experiment to obtain such data to enable design and optimization of the BFFL neutron filter.

  8. Proton and O sup(2-) ion diffusion studied by γ-γ angular correlation and by impedance spectroscopy

    International Nuclear Information System (INIS)

    Oliveira Damasceno, O. de.

    1988-01-01

    The interaction of sup(181) Ta quadrupole momentum with electric field gradient was measured by perturbed angular correlation spectroscopy in polycrystalline samples of hafnium hydride and hafnium oxide. The measurements were done as function of the temperature, in cubic and tetragonal phases of hafnium hydride. In the cubic phase, spin relaxation effects related to proton diffusion with activation energy of 0.43 ± 0.05eV were observed, and in the tetragonal phase, the interaction was purely static. The hafnium oxide was studied in cubic phase stabilized by addition of calcium oxide or magnesium oxide. Relaxation effects probably due to O sup(2-) ion diffusion were verified. The protonic conduction in K H sub(2) PO sub(4) was studied by impedance spectroscopy, in pellets prepared by melting or powder compression using silver and platinum electrodes. In the case of silver electrodes, in the low frequency region, the impedance spectrum tends to a 45 sup(0) typical line of the diffusion process. It was attributed to hydrogen injection in the electrode. Heating k H sub(2) PO sub(4) at about 230 sup(0)C modifies significantly the electric properties. Two relaxation annealing reduced conductivities to constant values independently of preparation method. (author)

  9. Complexing of zirconium and hafnium with ortho-aminobenzoic acid and paraaminobenzoic acid

    International Nuclear Information System (INIS)

    Alekseeva, I.I.; Nemzer, I.I.; Yuranova, L.I.; Borisova, V.V.; Prozorovskaya, Z.N.

    1977-01-01

    Formation of complexes between zirconium and hafnium and ortho- and para-aminobenzoic acids has been studied by the kinetic method. It has been found that at pH=1.3-2.0 and concentrations of metals 10 -5 -10 -6 mole complex compounds are formed with composition Me:L=1:2 and 1:1 (Me=Zr, Hf; L=ortho- or para-aminobenzoic acids). Stepwise constants and overall effective constants of complex formation have been calculated

  10. High temperature thermodynamics of solutions of oxygen in zirconium and hafnium

    International Nuclear Information System (INIS)

    Boureau, G.; Gerdanian, P.

    1984-01-01

    The Tian-Calvet microcalorimetric method has been applied to the determination at 1323 Kelvin of ΔH(O 2 ), the partial molar enthalpy of mixing of oxygen in zirconium and in hafnium. No measurable departure from Henry's law has been found for dilute solutions (ratio oxygen over metal smaller than 0.1). For concentrated solutions repulsive interactions are found in agreement with the existence of ordered structures at lower temperatures. The domain of homogeneity of zirconium has been found larger than previously assumed. (author)

  11. Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyralozone from aqueous-alcoholic solutions

    International Nuclear Information System (INIS)

    Hala, J.; Prihoda, J.

    1975-01-01

    Extraction of hafnium by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (HL) in benzene, toluene, chloroform and tetrachloromethane from aqueous-alcoholic solutions of the formal acidity of 2M-HClO 4 was studied. Methyl, ethyl, n- and isopropyl, tert-butyl and allyl alcohol as well as ethylene glycol monomethyl ether and propylene glycol were used as organic components of the mixed aqueous-organic phase. Their presence in some cases resulted in a synergic increase in the distribution ratio of hafnium. The increase is interpreted using the results of a slope analysis and measurements of the alcohol distribution and the relative permittivity of the organic phase. It is suggested that HfL 4 molecules were solvated by alcohol molecules in the organic phase. At high alcohol concentration synergism changed into antagonism. This was caused by changes in the distribution of HL and its interaction with the alcohol in the organic phase. (author)

  12. Trap state passivation improved hot-carrier instability by zirconium-doping in hafnium oxide in a nanoscale n-metal-oxide semiconductor-field effect transistors with high-k/metal gate

    International Nuclear Information System (INIS)

    Liu, Hsi-Wen; Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin; Chang, Ting-Chang; Chen, Ching-En; Tseng, Tseung-Yuen; Lin, Chien-Yu; Cheng, Osbert; Huang, Cheng-Tung; Ye, Yi-Han

    2016-01-01

    This work investigates the effect on hot carrier degradation (HCD) of doping zirconium into the hafnium oxide high-k layer in the nanoscale high-k/metal gate n-channel metal-oxide-semiconductor field-effect-transistors. Previous n-metal-oxide semiconductor-field effect transistor studies demonstrated that zirconium-doped hafnium oxide reduces charge trapping and improves positive bias temperature instability. In this work, a clear reduction in HCD is observed with zirconium-doped hafnium oxide because channel hot electron (CHE) trapping in pre-existing high-k bulk defects is the main degradation mechanism. However, this reduced HCD became ineffective at ultra-low temperature, since CHE traps in the deeper bulk defects at ultra-low temperature, while zirconium-doping only passivates shallow bulk defects.

  13. Determination of hafnium with the inductively coupled plasma (ICP)

    International Nuclear Information System (INIS)

    Wuensch, G.; Pose, K.

    1985-01-01

    The relative intensities of 198 hafnium lines in the Ar-ICP are listed. Spectral interference tables are given for the 9 analytically best lines, covering the range of +-60 pm around the Hf-lines. They include measured (not calculated) data of the interferent equivalent concentrations (IEC) and the critical concentration ratios (CCR) for 115 lines of all 34 possibly interfering elements. In many cases, these IEC- or CCR-data differ by 1 or 2 orders of magnitude from those calculated from intensities observed in the NBS-copper arc. Since no intense Hf-line is free from spectral interferences, examples are given for the calculation of the most suitable line for a known matrix. (orig.) [de

  14. Recoil Induced Room Temperature Stable Frenkel Pairs in a-Hafnium Upon Thermal Neutron Capture

    Science.gov (United States)

    Butz, Tilman; Das, Satyendra K.; Dey, Chandi C.; Ghoshal, Shamik

    2013-11-01

    Ultrapure hafnium metal (110 ppm zirconium) was neutron activated with a thermal neutron flux of 6:6 · 1012 cm-2s-1 in order to obtain 181Hf for subsequent time differential perturbed angular correlation (TDPAC) experiments using the nuclear probe 181Hf(β-) 181Ta. Apart from the expected nuclear quadrupole interaction (NQI) signal for a hexagonal close-packed (hcp) metal, three further discrete NQIs were observed with a few percent fraction each. The TDPAC spectra were recorded for up to 11 half lives with extreme statistical accuracy. The fitted parameters vary slightly within the temperature range between 248 K and 373 K. The signals corresponding to the three additional sites completely disappear after `annealing' at 453 K for one minute. Based on the symmetry of the additional NQIs and their temperature dependencies, they are tentatively attributed to Frenkel pairs produced by recoil due to the emission of a prompt 5:694 MeV -ray following thermal neutron capture and reported by the nuclear probe in three different positions. These Frenkel pairs are stable up to at least 373 K.

  15. Atom-vacancy ordering and magnetic susceptibility of nonstoichiometric hafnium carbide

    International Nuclear Information System (INIS)

    Gusev, A.I.; Zyryanova, A.N.

    1999-01-01

    Experimental results on magnetic susceptibility of nonstoichiometric hafnium carbide HfC y (0.6 0.71 , HfC 0.78 and HfC 0.83 in the range of 870-930 K the anomalies are revealed which are associated with superstructure short-range ordering in a non-metallics sublattice. It is shown that a short-range order in HfC 0.71 and HfC 0.78 carbides corresponds to Hf 3 C 2 ordered phase, and in HfC 0.83 carbide - to Hf 6 C 5 ordered phase. HfC 0.78 carbide is found to possesses zero magnetic susceptibility in temperature range 910-980 K [ru

  16. Hafnium carbide nanocrystal chains for field emitters

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang

    2014-01-01

    A hafnium carbide (HfC) nanostructure, i.e., HfC nanocrystal chain, was synthesized by a chemical vapor deposition (CVD) method. X-ray diffractometer, field-emission scanning electron microscope, transmission electron microscope, and energy-dispersive X-ray spectrometer were employed to characterize the product. The synthesized one-dimensional (1D) nanostructures with many faceted octahedral nanocrystals possess diameters of tens of nanometers to 500 nm and lengths of a few microns. The chain-like structures possess a single crystalline structure and preferential growth direction along the [1 0 0] crystal orientation. The growth of the chains occurred through the vapor–liquid–solid process along with a negative-feedback mechanism. The field emission (FE) properties of the HfC nanocrystal chains as the cold cathode emitters were examined. The HfC nanocrystal chains display good FE properties with a low turn-on field of about 3.9 V μm −1 and a high field enhancement factor of 2157, implying potential applications in vacuum microelectronics.

  17. Simplified method for gravimetric determination of zirconium or hafnium with α-hydroxy carboxylic acids

    International Nuclear Information System (INIS)

    Barbieri, R.S.; Rocha, J.C.; Terra, V.R.; Marques Netto, A.

    1989-01-01

    The conditions for gravimetric determination of zirconium or hafnium by glicoloc acids derivatives were studied by thermogravimetric analysis. The method utilized shownd that after precipitation, washing and drying of precipitates at 150 o C, the resulting solid was weighed in the form of [M (RCH(OH)COO) 4 ] (M = Zr, Hf; R + C 6 H 5 , β-C 10 H 7 , p-BrC 6 H 4 ). (author)

  18. Complexonometric determination of hafnium (4) in the presence of europium(3) or tantalum(5)

    International Nuclear Information System (INIS)

    Oziashvili, E.D.; Ehsakiya, K.E.; Sirakanyan, N.M.

    1986-01-01

    Complexonometric determination of hafnium in the presence of Ta or Eu in samples which can be decomposed by acids, i.e. in double borides has been investigated. Initial solutions are prepared by fusing with K 2 S 2 O 8 excess, the fusion was leached by hot water, H 2 SO L 4 was added and Hf was titrated by complexone 3 in the presence of xylenol orange

  19. Investigation of interaction of zirconium and hafnium tetrafluorides with strontium fluoride

    International Nuclear Information System (INIS)

    Ratnikova, I.D.; Korenev, Yu.M.; Novoselova, A.V.

    1980-01-01

    Diagrams of the condensated state of systems SrF 2 -EF 4 have been plotted, where E represents Zr, Hf. In these systems, three intermediate compounds of Sr 3 EF 10 , Sr 2 EF 8 and Sr EF 6 compositions are formed. All those compounds melt incongruently at temperatures of 982, 865 and 750 deg C, respectively - zirconium salt; at temperatures of 1000, 900 and 820 deg C - hafnium salts. Fluoro-metallates of composition 2:1, and 1:1, exist in two polymorphic forms. Tetrafluorides were found to dissolve in strontium fluoride: they form solid solutions having fluorite structure

  20. Laser coating of hafnium on Ti6Al4 for biomedical applications

    CSIR Research Space (South Africa)

    Phume, L

    2012-12-01

    Full Text Available Al4V FOR BIOMEDICAL APPLICATIONS Lerato Phume 1, 2, S.L. Pityana 1, 2, C. Meacock 1, A.P.I Popoola 2 1. National Laser Centre, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria, 0001, South Africa 2. Department of Chemical... and Metallurgical Engineering, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001, South Africa (b) (c) (e) To investigate laser surface coating of Ti6Al4V with preplaced Hafnium powder, to determine the influence of the energy density...

  1. Systematic investigation of electromagnetic properties of all stable hafnium isotopes

    International Nuclear Information System (INIS)

    Napiorkowski, T.J.; Choinski, J.; Czosnyka, T.; Iwanicki, J.; Kownacki, J.; Zemlo, L.; Srebrny, J.; Starosta, K.; Boer, J. de.; Gollwitzer, A.; Loewe, M.; Wuerkner, M.; Guenther, C.; Weber, T.; Hagemann, G.; Sletten, G.

    1996-01-01

    In a systematic investigation of the electromagnetic structure of hafnium stable isotopes enriched targets of 176, 177, 178, 179, 180 Hf were Coulomb exciting using: 67 MeV 19 F beam from NBITAL FN Tandem, 125 MeV 32 S beam from MP Tandem in Accelerator Laboratory LMU and TU Munich, 225 MeV 58 Ni beam from NBITAL FN Tandem plus 2 Liniac Boosters complex. Scattered particle-gamma as well as p-γ-γ coincidence were registered. A further simultaneous analysis of Coulomb excitation cross section as a function of scattering angle of 19 F, 32 S, 58 Ni projectiles should be sufficient to deduce reduced probabilities of E2 transitions in ground state band

  2. Highly substituted zirconium and hafnium cyclopentadienyl bifunctional β-diketiminate complexes – Synthesis, structure, and catalytic activity towards ethylene polymerization

    Czech Academy of Sciences Publication Activity Database

    Havlík, A.; Lamač, Martin; Pinkas, Jiří; Varga, Vojtěch; Růžička, A.; Olejník, R.; Horáček, Michal

    2015-01-01

    Roč. 786, JUN 2015 (2015), s. 71-80 ISSN 0022-328X R&D Projects: GA ČR GAP106/10/0924 Institutional support: RVO:61388955 Keywords : Zirconium * Hafnium * Cyclopentadienyl Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.336, year: 2015

  3. Wake-up effects in Si-doped hafnium oxide ferroelectric thin films

    International Nuclear Information System (INIS)

    Zhou, Dayu; Xu, Jin; Li, Qing; Guan, Yan; Cao, Fei; Dong, Xianlin; Müller, Johannes; Schenk, Tony; Schröder, Uwe

    2013-01-01

    Hafnium oxide based ferroelectric thin films have shown potential as a promising alternative material for non-volatile memory applications. This work reports the switching stability of a Si-doped HfO 2 film under bipolar pulsed-field operation. High field cycling causes a “wake-up” in virgin “pinched” polarization hysteresis loops, demonstrated by an enhancement in remanent polarization and a shift of negative coercive voltage. The rate of wake-up is accelerated by either reducing the frequency or increasing the amplitude of the cycling field. We suggest de-pinning of domains due to reduction of the defect concentration at bottom electrode interface as origin of the wake-up

  4. Extraction of hafnium with chelating agents from aqueous-alcoholic solutions

    International Nuclear Information System (INIS)

    Hala, J.; Prihoda, J.

    1975-01-01

    The extraction was studied of hafnium into solutions of N-benzoyl-N-phenylhydroxylamine, 2-thenoyltrifluoroacetone and di-n-butylphosphoric acid in benzene, toluene, chloroform and tetrachloromethane from aqueous alcoholic solutions with a formal acidity of 2M-HClO 4 . Methyl-, ethyl-, n- and isopropyl- and tert-butyl alcohol were used as organic components in the mixed aqueous-organic phase. In the extraction into N-benzoyl-N-phenylhydroxylamine the presence of the alcohols resulted in synergic effects analogous to the previously described extraction by substituted benzoylpyrazolone. With the other two extractants, the effect of the alcohols was antagonistic, due to the interaction of alcohol or water with the reagent in the organic phase, and to the decrease in the reagent distribution constant. (author)

  5. Studies of high-K isomers in hafnium nuclei

    International Nuclear Information System (INIS)

    Sletten, G.; Gjoerup, N.L.

    1991-01-01

    K-isomeric states built on high-Ω Nilsson orbitals from deformation-aligned high-j levels near the Fermi surface are found to cluster in the neutron rich Hf, W and Os nuclei. It has been shown that some of the high seniority states of this type have decay properties that indicate strong mixing of configurations and that in Osmium nuclei γ-softness cause strong deviations from the well established K-selection rule. Also in the Hafnium nuclei is the expected forbiddenness in isomeric decays an order of magnitude smaller than expected from the K-selection rule. A new 9 quasiparticle isomer has been discovered in 175 Hf at I=57/2. This isomer has the anomalous decay as the dominant mode. Other lower seniority states are also identified. At spin 35/2 and 45/2 the deformation aligned states become yrast, but the structure of the yrast line to even higher spins is not yet understood. (author)

  6. Luminescent determination of zirconium and hafnium with myricetin

    International Nuclear Information System (INIS)

    Talipov, Sh.T.; Zel'tser, L.E.; Morozova, L.A.; Tashkhodzhaev, A.T.

    1978-01-01

    Reaction of formation of 3, 5, 7, 3', 4', 5' - hexaoxiflavone - myricetin complexes with zirconium and hafnium ions has been the basis for development of luminescent method of determining these elements. Optimum conditions for complexing have been determined. For Hf they are : 8-9 HCl concentration, maximum fluorescence wave length (lambda fl.)of 520 nm, wave length of exciting light (lambda el) of 436 nm, for Zr lambda fl = 536nm, lambda el = 436 nm. Stable fluorescence establishes after 25 min. for Zr and after 15 min for Hf in the presence of 40% ethanol. Usage of various camouflage agents has permitted to attain high selectivity of the method. Possibility for determination of Zr with myricetin in the presence of a 10-time excess of Hf, Cr, Cu, 50-time excess of Mo and Ti is shown. Sensitivity of Zr determination is 2.0x10 μg -2 /ml, for Hf it is 9.0x10 μg -3 and mineral waters

  7. Amorphous Hafnium-Indium-Zinc Oxide Semiconductor Thin Film Transistors

    Directory of Open Access Journals (Sweden)

    Sheng-Po Chang

    2012-01-01

    Full Text Available We reported on the performance and electrical properties of co-sputtering-processed amorphous hafnium-indium-zinc oxide (α-HfIZO thin film transistors (TFTs. Co-sputtering-processed α-HfIZO thin films have shown an amorphous phase in nature. We could modulate the In, Hf, and Zn components by changing the co-sputtering power. Additionally, the chemical composition of α-HfIZO had a significant effect on reliability, hysteresis, field-effect mobility (μFE, carrier concentration, and subthreshold swing (S of the device. Our results indicated that we could successfully and easily fabricate α-HfIZO TFTs with excellent performance by the co-sputtering process. Co-sputtering-processed α-HfIZO TFTs were fabricated with an on/off current ratio of ~106, higher mobility, and a subthreshold slope as steep as 0.55 V/dec.

  8. Rhodium and Hafnium Influence on the Microstructure, Phase Composition, and Oxidation Resistance of Aluminide Coatings

    OpenAIRE

    Maryana Zagula-Yavorska; Małgorzata Wierzbińska; Jan Sieniawski

    2017-01-01

    A 0.5 μm thick layer of rhodium was deposited on the CMSX 4 superalloy by the electroplating method. The rhodium-coated superalloy was hafnized and aluminized or only aluminized using the Chemical vapour deposition method. A comparison was made of the microstructure, phase composition, and oxidation resistance of three aluminide coatings: nonmodified (a), rhodium-modified (b), and rhodium- and hafnium-modified (c). All three coatings consisted of two layers: the additive layer and the interdi...

  9. Study of bulk Hafnium oxide (HfO2) under compression

    Science.gov (United States)

    Pathak, Santanu; Mandal, Guruprasad; Das, Parnika

    2018-04-01

    Hafnium oxide (HfO2) is a technologically important material. This material has K-value of 25 and band gap 5.8 eV. A k value of 25-30 is preferred for a gate dielectric [1]. As it shows good insulating and capacitive properties, HfO2 is being considered as a replacement to SiO2 in microelectronic devices as gate dielectrics. On the other hand because of toughening mechanism due to phase transformation induced by stress field observed in these oxides, HFO2 has been a material of investigations in various configurations for a very long time. However the controversies about phase transition of HfO2 under pressure still exists. High quality synchrotron radiation has been used to study the structural phase transition of HfO2 under pressure.

  10. Hafnium at subduction zones: isotopic budget of input and output fluxes; L'hafnium dans les zones de subduction: bilan isotopique des flux entrant et sortant

    Energy Technology Data Exchange (ETDEWEB)

    Marini, J.Ch

    2004-05-15

    Subduction zones are the primary regions of mass exchanges between continental crust and mantle of Earth through sediment subduction toward the earth's mantle and by supply of mantellic magmas to volcanic arcs. We analyze these mass exchanges using Hafnium and Neodymium isotopes. At the Izu-Mariana subduction zone, subducting sediments have Hf and Nd isotopes equivalent to Pacific seawater. Altered oceanic crust has Hf and Nd isotopic compositions equivalent to the isotopic budget of unaltered Pacific oceanic crust. At Luzon and Java subduction zones, arc lavas present Hf isotopic ratios highly radiogenic in comparison to their Nd isotopic ratios. Such compositions of the Luzon and Java arc lavas are controlled by a contamination of their sources by the subducted oceanic sediments. (author)

  11. Correlações entre caracteres quantitativos em milho pipoca Correlation among quantitative traits in popcorn maize

    Directory of Open Access Journals (Sweden)

    Valéria Carpentieri-Pípolo

    2002-12-01

    Full Text Available Em um programa de melhoramento, o conhecimento da grandeza das associações entre caracteres de interesse, é de fundamental importância na obtenção de populações melhoradas. O presente trabalho teve como objetivo determinar as correlações genotípicas, fenotípicas e ambientais entre caracteres quantitativos em milho pipoca. Foram avaliados nove genótipos de milho pipoca dispostos no campo em delineamento em blocos casualizados com oito repetições. Os genótipos UEL ZP, UEL SI e UEL PAP revelaram maiores capacidades de expansão (27,50; 27,15 e 24,40 respectivamente e número de grãos por volume (244,75; 248,50 e 248,75 respectivamente. A capacidade de expansão revelou correlação fenotípica positiva com o tamanho da pipoca e com o número de grãos por volume, e correlação negativa com massa de grãos por planta. Os caracteres massa de grãos por planta e peso total da espiga revelaram correlações fenotípicas e genotípicas positivas entre si, o que possibilita a utilização de um ou outro na seleção, optando-se pelo que melhor convier aos propósitos do programa de melhoramento.Knowledge of the size of the association among traits of interest is of fundamental importance in a breeding program to allow genetic progress. The genotypic, phenotypic and environment correlation were studied among quantitative traits of popcorn maize. Nine popcorn maize genotypes were assessed. A randomized complete block design with eight replications was used. The UEL ZP, UEL SI and UEL PAP. genotypes which had greatest expansion capacity (27.50; 27.15 and 24.20, respectively, also had the greatest values for the number of grains per volume (244.75; 248.50 and 248.75, respectively. The expansion capacity correlated positively with the popcorn size and with number of grains per volume and negatively with plant yield. The traits plant yield, and total ear weight showed positive phenotypic and genotypic correlation that permits the choice of

  12. Hafnium at subduction zones: isotopic budget of input and output fluxes

    International Nuclear Information System (INIS)

    Marini, J.Ch.

    2004-05-01

    Subduction zones are the primary regions of mass exchanges between continental crust and mantle of Earth through sediment subduction toward the earth's mantle and by supply of mantellic magmas to volcanic arcs. We analyze these mass exchanges using Hafnium and Neodymium isotopes. At the Izu-Mariana subduction zone, subducting sediments have Hf and Nd isotopes equivalent to Pacific seawater. Altered oceanic crust has Hf and Nd isotopic compositions equivalent to the isotopic budget of unaltered Pacific oceanic crust. At Luzon and Java subduction zones, arc lavas present Hf isotopic ratios highly radiogenic in comparison to their Nd isotopic ratios. Such compositions of the Luzon and Java arc lavas are controlled by a contamination of their sources by the subducted oceanic sediments. (author)

  13. Thermal expansion studies on Hafnium titanate (HfTiO4)

    International Nuclear Information System (INIS)

    Panneerselvam, G.; Subramanian, G.G.S.; Antony, M.P.

    2006-01-01

    The lattice thermal expansion characteristics of hafnium titanate (HfTiO 4 ) have been studied by measuring the lattice parameter as a function of temperature by high temperature X-ray diffraction technique (HT-XRD) in the temperature range 298-1973K. Percentage linear thermal expansion and mean linear thermal expansion coefficients were computed from the lattice parameter data. The thermal expansion of HfTiO 4 is highly anisotropic. The expansivity along 'a' axis is large; as compared to the expansivity along 'b' axis which is negative below 1073 K. The percentage linear thermal expansion in the temperature range 298-1973 K along a, b and c axis are 2.74, 0.901 and 1.49 respectively. Thermal expansion values obtained in the present study are in reasonable agreement with the existing thermal expansion data. (author)

  14. Surface State Capture Cross-Section at the Interface between Silicon and Hafnium Oxide

    Directory of Open Access Journals (Sweden)

    Fu-Chien Chiu

    2013-01-01

    Full Text Available The interfacial properties between silicon and hafnium oxide (HfO2 are explored by the gated-diode method and the subthreshold measurement. The density of interface-trapped charges, the current induced by surface defect centers, the surface recombination velocity, and the surface state capture cross-section are obtained in this work. Among the interfacial properties, the surface state capture cross-section is approximately constant even if the postdeposition annealing condition is changed. This effective capture cross-section of surface states is about 2.4 × 10−15 cm2, which may be an inherent nature in the HfO2/Si interface.

  15. A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

    Directory of Open Access Journals (Sweden)

    S. Riedel

    2016-09-01

    Full Text Available Ferroelectric properties in hafnium oxide based thin films have recovered the scaling potential for ferroelectric memories due to their ultra-thin-film- and CMOS-compatibility. However, the variety of physical phenomena connected to ferroelectricity allows a wider range of applications for these materials than ferroelectric memory. Especially mixed HfxZr1-xO2 thin films exhibit a broad compositional range of ferroelectric phase stability and provide the possibility to tailor material properties for multiple applications. Here it is shown that the limited thermal stability and thick-film capability of HfxZr1-xO2 can be overcome by a laminated approach using alumina interlayers.

  16. Influence of plastic deformation on nitriding of a molybdenum-hafnium alloy

    International Nuclear Information System (INIS)

    Lakhtin, Yu.M.; Kogan, Ya.D.; Shashkov, D.P.; Likhacheva, T.E.

    1982-01-01

    The influence of a preliminary plastic strain on the structure and properties of molybdenum alloy with 0.2 wt.% Hf upon nitriding in the ammonia medium at 900-1200 deg C during 1-6 h is investigated. The study of microhardness distribution across the nitrided layer thickness has shown that with increase of the degree of preliminary plastic strain up to 50 % the nitrided layer hardness decreases and with further reduction growth up to 90 % - increases. Nitriding sharply (hundred times) increases wear resistance of molybdenum alloy with hafnium addition. At the reduction degree 25 % the wear resistance is less than at other values of percentage reduction in area owing to the minimum thickness of the nitride zone. The alloy strained before nitriding by 25 % has shown the best results during heat resistance testing

  17. Dielectric response and ac conductivity analysis of hafnium oxide nanopowder

    International Nuclear Information System (INIS)

    Karahaliou, P K; Xanthopoulos, N; Krontiras, C A; Georga, S N

    2012-01-01

    The dielectric response of hafnium oxide nanopowder was studied in the frequency range of 10 -2 -10 6 MHz and in the temperature range of 20-180 °C. Broadband dielectric spectroscopy was applied and the experimental results were analyzed and discussed using the electric modulus (M*) and alternating current (ac) conductivity formalisms. The analyses of the dc conductivity and electric modulus data revealed the presence of mechanisms which are thermally activated, both with almost the same activation energy of 1.01 eV. A fitting procedure involving the superposition of the thermally activated dc conductivity, the universal dielectric responce and the near constant loss terms has been used to describe the frequency evolution of the real part of the specific electrical conductivity. The conductivity master curve was obtained, suggesting that the time-temperature superposition principle applies for the studied system, thus implying that the conductivity mechanisms are temperature independent.

  18. Interface and oxide traps in high-κ hafnium oxide films

    International Nuclear Information System (INIS)

    Wong, H.; Zhan, N.; Ng, K.L.; Poon, M.C.; Kok, C.W.

    2004-01-01

    The origins of the interface trap generation and the effects of thermal annealing on the interface and bulk trap distributions are studied in detail. We found that oxidation of the HfO 2 /Si interface, removal of deep trap centers, and crystallization of the as-deposited film will take place during the post-deposition annealing (PDA). These processes will result in the removal of interface traps and deep oxide traps and introduce a large amount of shallow oxide traps at the grain boundaries of the polycrystalline film. Thus, trade-off has to be made in considering the interface trap density and oxide trap density when conducting PDA. In addition, the high interface trap and oxide trap densities of the HfO 2 films suggest that we may have to use the SiO 2 /HfO 2 stack or hafnium silicate structure for better device performance

  19. Effects of oxygen partial pressure and annealing temperature on the residual stress of hafnium oxide thin-films on silicon using synchrotron-based grazing incidence X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Debaleen [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Sinha, Anil Kumar [ISU, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India); Homi Bhabha National Institute, BARC, Mumbai 400 094 (India); Chakraborty, Supratic, E-mail: supratic.chakraborty@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)

    2016-10-30

    Highlights: • Residual stress estimation thin hafnium oxide film with thickness of <10 nm. • A mathematical expression is proposed for stress estimation of thin-film using GIXRD. • Residual stress varies with argon content in Ar/O{sub 2} plasma and annealing temperature. • Variation of stress is explained by IL swelling and enhanced structural relaxation. - Abstract: Synchrotron radiation-based grazing incidence X-ray diffraction (GI-XRD) technique is employed here to estimate the residual stress of < 10 nm thin hafnium oxide film deposited on Si (100) substrate at different argon/oxygen ratios using reactive rf sputtering. A decrease in residual stress, tensile in nature, is observed at higher annealing temperature for the samples deposited with increasing argon ratio in the Ar/O{sub 2} plasma. The residual stress of the films deposited at higher p{sub Ar} (Ar:O{sub 2} = 4:1) is also found to be decreased with increasing annealing temperature. But the stress is more or less constant with annealing temperature for the films deposited at lower Ar/O{sub 2} (1:4) ratio. All the above phenomena can be explained on the basis of swelling of the interfacial layer and enhanced structural relaxation in the presence of excess Hf in hafnium oxide film during deposition.

  20. Correlação entre peso fetal estimado por ultrassonografia e peso neonatal Correlation between estimated fetal weight by ultrasound and neonatal weight

    Directory of Open Access Journals (Sweden)

    Djacyr Magna Cabral Freire

    2010-01-01

    Full Text Available OBJETIVO: avaliar a correlação entre o peso fetal estimado (PFE por ultrassonografia e o peso neonatal (PN, bem como a capacidade do PFE predizer as alterações do PN entre gestantes de João Pessoa (PB. MÉTODOS: estudo de validação diagnóstica incluindo 122 gestantes que tiveram o PFE calculado por ultrassonografia até sete dias antes do parto e o PN determinado imediatamente após o nascimento, com balança específica para recém-nascidos. A correlação entre o PFE e o PN foi avaliada pelo coeficiente de correlação de Pearson entre as duas medidas e pela média das diferenças entre elas. O PFE e o PN foram classificados em: pequeno para idade gestacional (PIG, adequado para a idade gestacional (AIG e grande para a idade gestacional (GIG, de acordo com os percentis 10 e 90 das respectivas curvas de referência. O diagnóstico de desvios do PFE foi validado utilizando a curva de valores de referência de peso neonatal de Alexander como padrão-ouro, estimando-se a sensibilidade, especificidade, valores preditivos positivo e negativo. RESULTADOS: houve uma elevada correlação linear entre o PFE e o PN (R=0,96 e a diferença entre eles variou entre -474 g e +480 g, com média de +3 g. A maioria das máximas variações percentuais da estimativa de peso esteve entre 10 e 15%. O PFE teve sensibilidade de 85,7% e especificidade de 100% para detecção de PIG, e de 100 e 77,2%, respectivamente, para GIG. CONCLUSÕES: o PFE é capaz de predizer adequadamente o PN, e a curva de PFE de referência testada teve bom desempenho no rastreamento dos desvios do crescimento fetal, quando utilizada nessa população.PURPOSE: to evaluate the correlation between the estimated fetal weight (EFW by ultrasonography and the neonatal weight (NW, as well as the EFW's capacity to predict changes in NW among pregnant women in João Pessoa, Paraíba, Brazil. METHODS: a diagnostic validation study, including 122 pregnant women who have had the EFW calculated

  1. Implantation of titanium, chromium, yttrium, molybdenum, silver, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum ion source into 440C stainless steel

    International Nuclear Information System (INIS)

    Sasaki, Jun; Hayashi, Kazunori; Sugiyama, Kenji; Ichiko, Osami; Hashiguchi, Yoshihiro

    1992-01-01

    Titanium, yttrium, molybdenum, silver, chromium, hafnium, tantalum, tungsten and platinum ions generated by a metal vapor vacuum arc (MEVVA) ion source were implanted into 440C stainless steel in the dose region 10 17 ions cm -2 with extraction voltages of up to 70 kV. Glow discharge spectroscopy (GDS), friction coefficient, and Vickers microhardness of the specimens were studied. Grooves made by friction tests were investigated by electron probe microanalysis (EPMA). GDS showed incorporation of carbon in the yttrium, hafnium, tantalum, tungsten and platinum implanted specimens, as well as titanium implanted samples. A large amount of oxygen was observed in the yttrium implanted specimen. The friction coefficient was measured by reciprocating sliding of an unimplanted 440C ball without lubricant at a load of 0.245 N. The friction decreased and achieved a stable state after implantation of titanium, hafnium and tantalum. The friction coefficient of the platinum implanted specimen showed a gradual decrease after several cycles of sliding at high friction coefficient. The yttrium implanted sample exhibited a decreased but slightly unstable friction coefficient. Results from EPMA showed that the implanted elements, which gave decreased friction, remained even after sliding of 200 cycles. Implantation of chromium, molybdenum, silver and tungsten did not provide a decrease in friction and the implants were gone from the wear grooves after the sliding tests. (orig.)

  2. Critical evaluation of the determination of zirconium and hafnium by instrumental and radiochemical neutron activation analysis

    International Nuclear Information System (INIS)

    Burger, Mario; Kraehenbuehl, Urs

    1991-01-01

    Neutron activation analysis (instrument or radiochemical) is suitable for the determination of zirconium and hafnium in samples of geochemical origin only when sufficient attention is paid to inter-fering nuclides. The size of the necessary correction for INAA depends on the composition of the sample; this problem is discussed. The radio-chemical technique which is recommended involves separation of the samples, precipitations and anion-exchange separation. Results are given for various standard reference materials and for meteorites. (author). 12 refs.; 1 fig.; 9 tabs

  3. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    International Nuclear Information System (INIS)

    Rezaei, B.; Meghdadi, S.; Zarandi, R. Fazel

    2008-01-01

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis(α-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf 4+ (Hafnium(IV)) over a wide concentration range (2.0 x 10 -7 to 1.0 x 10 -1 M) with the determination coefficient of 0.9966 and slope of 15.1 ± 0.1 mV decades -1 . The limit of detection is 1.9 x 10 -7 M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf 4+ ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf 4+ in solutions by standard addition method for real sample analysis

  4. Study of hafnium (IV) oxide nanoparticles synthesized by polymerized complex and polymer precursor derived sol-gel methods

    KAUST Repository

    Ramos-Gonzá lez, R.; Garcí a-Cerda, L. A.; Alshareef, Husam N.; Gnade, Bruce E.; Quevedo-Ló pez, Manuel Angel Quevedo

    2010-01-01

    This work reports the preparation and characterization of hafnium (IV) oxide (HfO2) nanoparticles grown by derived sol-gel routes that involves the formation of an organic polymeric network. A comparison between polymerized complex (PC) and polymer precursor (PP) methods is presented. For the PC method, citric acid (CA) and ethylene glycol (EG) are used as the chelating and polymerizable reagents, respectively. In the case of PP method, poly(acrylic acid) (PAA) is used as the chelating reagent. In both cases, different precursor gels were prepared and the hafnium (IV) chloride (HfCl4) molar ratio was varied from 0.1 to 1.0 for the PC method and from 0.05 to 0.5 for the PP method. In order to obtain the nanoparticles, the precursors were heat treated at 500 and 800 °C. The thermal characterization of the precursor gels was carried out by thermogravimetric analysis (TGA) and the structural and morphological characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the samples obtained by both methods shows the formation of HfO2 at 500 °C with monoclinic crystalline phase. The PC method exhibited also the cubic phase. Finally, the HfO2 nanoparticles size (4 to 11 nm) was determined by TEM and XRD patterns. © (2010) Trans Tech Publications.

  5. Study of hafnium (IV) oxide nanoparticles synthesized by polymerized complex and polymer precursor derived sol-gel methods

    KAUST Repository

    Ramos-González, R.

    2010-03-01

    This work reports the preparation and characterization of hafnium (IV) oxide (HfO2) nanoparticles grown by derived sol-gel routes that involves the formation of an organic polymeric network. A comparison between polymerized complex (PC) and polymer precursor (PP) methods is presented. For the PC method, citric acid (CA) and ethylene glycol (EG) are used as the chelating and polymerizable reagents, respectively. In the case of PP method, poly(acrylic acid) (PAA) is used as the chelating reagent. In both cases, different precursor gels were prepared and the hafnium (IV) chloride (HfCl4) molar ratio was varied from 0.1 to 1.0 for the PC method and from 0.05 to 0.5 for the PP method. In order to obtain the nanoparticles, the precursors were heat treated at 500 and 800 °C. The thermal characterization of the precursor gels was carried out by thermogravimetric analysis (TGA) and the structural and morphological characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the samples obtained by both methods shows the formation of HfO2 at 500 °C with monoclinic crystalline phase. The PC method exhibited also the cubic phase. Finally, the HfO2 nanoparticles size (4 to 11 nm) was determined by TEM and XRD patterns. © (2010) Trans Tech Publications.

  6. Rapid formation of nanocrystalline HfO2 powders from amorphous hafnium hydroxide under ultrasonically assisted hydrothermal treatment

    International Nuclear Information System (INIS)

    Meskin, Pavel E.; Sharikov, Felix Yu.; Ivanov, Vladimir K.; Churagulov, Bulat R.; Tretyakov, Yury D.

    2007-01-01

    Peculiarities of hafnium hydroxide hydrothermal decomposition were studied by in situ heat flux calorimetry for the first time. It was shown that this process occurs in one exothermal stage (ΔH = -17.95 kJ mol -1 ) at 180-250 deg. C resulting in complete crystallization of amorphous phase with formation of pure monoclinic HfO 2 . It was found that the rate of m-HfO 2 formation can be significantly increased by combining hydrothermal treatment with simultaneous ultrasonic activation

  7. Improvement of aging kinetics and precipitate size refinement in Mg–Sn alloys by hafnium additions

    Energy Technology Data Exchange (ETDEWEB)

    Behdad, S. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Zhou, L. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Henderson, H.B.; Manuel, M.V. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Sohn, Y. [Department of Materials Science and Engineering and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816 (United States); Agarwal, A. [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Boesl, B., E-mail: bboesl@fiu.edu [Department of Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

    2016-01-10

    Two Mg–Sn alloys were microalloyed by addition of Hafnium and their age-hardening response was studied at 200 °C. Time to reach peak hardness was significantly reduced and improved by Hf addition. TEM study showed Hf clusters in the close vicinity and at the surface of Mg{sub 2}Sn precipitates, which confirms that Hf clusters act as additional nucleation centers for Mg{sub 2}Sn precipitate formation. Our results support the validity of thermokinetic criterion proposed by Mendis for selection of microalloying elements in order to refine precipitate size, accelerate aging kinetics and enhance peak hardness.

  8. Solvent extraction of hafnium(IV) by dinonylnaphthalene sulfonic acid from mixed aqueous-organic media

    International Nuclear Information System (INIS)

    Hala, J.; Piperkovova, H.

    1979-01-01

    The extraction of hafnium(IV) by heptane and toluene solutions of dinonylnaphthalene sulfonic acid (HD) from mixed aqueous-organic solutions has been studied. Alcohols, ketones, carboxylic acids, cyclic ethers, dimethylsulfoxide and dimethylformamide were used as the organic component of the mixed phase. Methanol, ethanol, formic acid and dioxane increased the extractability of Hf(IV) whereas other solvents showed only an antagonistic effect. The results were discussed from the point of view of the changes in micellar structure of HD, and compared with the uptake of Hf(IV) by resinous cation exchangers. The solubilization by HD of alcohols, carboxylic acids and dimethylsulfoxide was demonstrated by using the corresponding 14 C and 35 S labelled compounds. (author)

  9. The interfacial orientation relationship of oxide nanoparticles in a hafnium-containing oxide dispersion-strengthened austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yinbin, E-mail: miao2@illinois.edu [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Mo, Kun [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60493 (United States); Cui, Bai [Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588 (United States); Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Chen, Wei-Ying [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Miller, Michael K.; Powers, Kathy A. [Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37830 (United States); McCreary, Virginia; Gross, David [Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Almer, Jonathan [X-ray Science Division, Argonne National Laboratory, Lemont, IL 60493 (United States); Robertson, Ian M. [Department of Material Science and Engineering, University of Wisconsin-Madison, Madison, WA 53706 (United States); Department of Material Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States); Stubbins, James F. [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2015-03-15

    This work reports comprehensive investigations on the orientation relationship of the oxide nanoparticles in a hafnium-containing austenitic oxide dispersion-strengthened 316 stainless steel. The phases of the oxide nanoparticles were determined by a combination of scanning transmission electron microscopy–electron dispersive X-ray spectroscopy, atom probe tomography and synchrotron X-ray diffraction to be complex Y–Ti–Hf–O compounds with similar crystal structures, including bixbyite Y{sub 2}O{sub 3}, fluorite Y{sub 2}O{sub 3}–HfO{sub 2} solid solution and pyrochlore (or fluorite) Y{sub 2}(Ti,Hf){sub 2−x}O{sub 7−x}. High resolution transmission electron microscopy was used to characterize the particle–matrix interfaces. Two different coherency relationships along with one axis-parallel relation between the oxide nanoparticles and the steel matrix were found. The size of the nanoparticles significantly influences the orientation relationship. The results provide insight into the relationship of these nanoparticles with the matrix, which has implications for interpreting material properties as well as responses to radiation. - Highlights: • The oxide nanoparticles in a hafnium-containing austenitic ODS were characterized. • The nanoparticles are Y–Hf–Ti–O enriched phases according to APT and STEM–EDS. • Two coherency and an axis-parallel orientation relationships were found by HR-TEM. • Particle size has a prominent effect on the orientation relationship (OR). • Formation mechanism of the oxide nanoparticles was discussed based on the ORs.

  10. Hafnium oxide nanoparticles: toward an in vitro predictive biological effect?

    International Nuclear Information System (INIS)

    Marill, Julie; Anesary, Naeemunnisa Mohamed; Zhang, Ping; Vivet, Sonia; Borghi, Elsa; Levy, Laurent; Pottier, Agnes

    2014-01-01

    Hafnium oxide, NBTXR3 nanoparticles were designed for high dose energy deposition within cancer cells when exposed to ionizing radiation. The purpose of this study was to assess the possibility of predicting in vitro the biological effect of NBTXR3 nanoparticles when exposed to ionizing radiation. Cellular uptake of NBTXR3 nanoparticles was assessed in a panel of human cancer cell lines (radioresistant and radiosensitive) by transmission electron microscopy. The radioenhancement of NBTXR3 nanoparticles was measured by the clonogenic survival assay. NBTXR3 nanoparticles were taken up by cells in a concentration dependent manner, forming clusters in the cytoplasm. Differential nanoparticle uptake was observed between epithelial and mesenchymal or glioblastoma cell lines. The dose enhancement factor increased with increase NBTXR3 nanoparticle concentration and radiation dose. Beyond a minimum number of clusters per cell, the radioenhancement of NBTXR3 nanoparticles could be estimated from the radiation dose delivered and the radiosensitivity of the cancer cell lines. Our preliminary results suggest a predictable in vitro biological effect of NBTXR3 nanoparticles exposed to ionizing radiation

  11. Nano-scale Radiotherapy-NBTXR3 Hafnium Oxide Nanoparticles as Promising Cancer Therapy

    International Nuclear Information System (INIS)

    Maggiorella, L.; Barouch, G.; Devaux, C.; Pottier, A.; Levy, L.; Deutsch, E.; Bourhis, J.; Borghi, E.

    2011-01-01

    Complete text of publication follows: Background: There is considerable interest in approaches that could improve the therapeutic window of radiotherapy, which represents a crucial modality of treatment in oncology. We present the rationale for designing NBTXR3 nanoparticles activated by radiotherapy and validate the concept. We performed the Monte Carlo calculations for the first time based on the 'local model' simulation that showed a dose enhancement of radiation to tumour cells of approximately nine-fold. NBTXR3 was shown to deposit high energy when the ionizing radiation source is 'on' and to have chemically inert behavior in cellular and subcellular systems demonstrated by very good systemic tolerance, thus decreasing potential health hazards. Material and Methods: We used conventional methods, implemented in different ways, to explore interactions of high Z matter and ionizing radiation with biological systems. In addition, microtomography was performed to explore the nanoparticle volume occupancy inside the tumour and its persistence overtime in mouse tumour models. The antitumour activity of NBTXR3 and tolerance were evaluated in Ewing tumour (A673) and fibrosarcoma (HT1080) using high energy source. Results and Conclusion: We created and developed NBTXR3 nanoparticles with a crystalline hafnium oxide core which provide high electron density structure and inert behavior in biological media. NBTXR3 nanoparticles' characteristics, size, charge and shape, allow for efficient interaction with biological entities, cell membrane binding and cellular uptake. The nanoparticles were shown to form clusters at the subcellular level in tumour models. Of most importance, we show NBTXR3 intra-tumour bioavailability with dispersion of nanoparticles in the three dimensions and persistence within the tumour structure, supporting the use of NBTXR3 as effective antitumour therapeutic agent. Antitumour activity of NBTXR3 showed marked advantage in terms of survival, tumour

  12. A fast response hafnium selective polymeric membrane electrode based on N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine as a neutral carrier

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, B. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)], E-mail: rezaei@cc.iut.ac.ir; Meghdadi, S.; Zarandi, R. Fazel [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2008-08-30

    In this study a new hafnium selective sensor was fabricated from polyvinylchloride (PVC) matrix membrane containing neutral carrier N,N'-bis({alpha}-methyl-salicylidene)-dipropylenetriamine (Mesaldpt) as a new ionophore, sodium tetraphenyl borate (NaTPB) as anionic discriminator and dioctyl phthalate (DOP) as plasticizing solvent mediator in tetrahydrofuran solvent. The electrode exhibits Nernstian response for Hf{sup 4+} (Hafnium(IV)) over a wide concentration range (2.0 x 10{sup -7} to 1.0 x 10{sup -1} M) with the determination coefficient of 0.9966 and slope of 15.1 {+-} 0.1 mV decades{sup -1}. The limit of detection is 1.9 x 10{sup -7} M. The electrode has a fast response time of 18 s and a working pH range of 4-8. The proposed membrane shows excellent discriminating ability towards Hf{sup 4+} ion with regard to several alkali, alkaline earth transition and heavy metal ions. It can be used over a period of 1.5 months with good reproducibility. It is successfully applied for direct determination of Hf{sup 4+} in solutions by standard addition method for real sample analysis.

  13. Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment.

    Science.gov (United States)

    Chen, Min-Hua; Hanagata, Nobutaka; Ikoma, Toshiyuki; Huang, Jian-Yuan; Li, Keng-Yuan; Lin, Chun-Pin; Lin, Feng-Huei

    2016-06-01

    Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure. Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible

  14. Sub-10 nm low current resistive switching behavior in hafnium oxide stack

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Y., E-mail: houyi@pku.edu.cn, E-mail: lfliu@pku.edu.cn [Institute of Microelectronics, Peking University, 100871 Beijing (China); IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Celano, U.; Xu, Z.; Vandervorst, W. [IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Department of Physics and Astronomy, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Goux, L.; Fantini, A.; Degraeve, R.; Youssef, A.; Jurczak, M. [IMEC, Kapeldreef 75, B-3001 Heverlee (Belgium); Liu, L., E-mail: houyi@pku.edu.cn, E-mail: lfliu@pku.edu.cn; Cheng, Y.; Kang, J. [Institute of Microelectronics, Peking University, 100871 Beijing (China)

    2016-03-21

    In this letter, a tip-induced cell relying on the conductive atomic force microscope is proposed. It is verified as a referable replica of an integrated resistive random access memory (RRAM) device. On the basis of this cell, the functionality of sub-10 nm resistive switching is confirmed in hafnium oxide stack. Moreover, the low current switching behavior in the sub-10 nm dimension is found to be more pronounced than that of a 50 × 50 nm{sup 2} device. It shows better ON/OFF ratio and low leakage current. The enhanced memory performance is ascribed to a change in the shape of the conductive filament as the device dimensions are reduced to sub-10 nm. Therefore, device downscaling provides a promising approach for the resistance optimization that benefits the RRAM array design.

  15. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    Energy Technology Data Exchange (ETDEWEB)

    Salyulev, A B; Kudyakov, V Ya; Smirnov, M V; Moskalenko, N I [AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii

    1984-08-01

    The coefficient of HfCl/sub 4/ and ZrCl/sub 4/ separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl/sub 4/+HfCl/sub 4/). HfCl/sub 4/ and ZrCl/sub 4/ are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl.

  16. Separation of hafnium from zirconium in their tetrachloride solution in molten alkali metal chlorides

    International Nuclear Information System (INIS)

    Salyulev, A.B.; Kudyakov, V.Ya.; Smirnov, M.V.; Moskalenko, N.I.

    1984-01-01

    The coefficient of HfCl 4 and ZrCl 4 separation in the process of vapour sublimation from their solutions in molten NaCl, KCl, CsCl, NaCl-KCl and NaCl-CsCl equimolar mixtures is found to vary in the series from approximately 1.10 to approximately 1.22 and practically not to depend on the temperature (in the 600-910 deg) range and concentration (2-25 mol.% ZrCl 4 +HfCl 4 ). HfCl 4 and ZrCl 4 are shown to form almost perfect solutions with each other, which in their turn form imperfect solutions with molten alkali metal chlorides, with the strength of hafnium complex chloride anions increasing higher than that of zirconium in the series from NaCl to CsCl

  17. Correlações entre ruído ambiental em sala de aula e voz do professor Correlations between classroom environmental noise and teachers' voice

    Directory of Open Access Journals (Sweden)

    Rafaela Fernanda Guidini

    2012-12-01

    Full Text Available OBJETIVO: Identificar se existe correlação entre ruído ambiental no interior da sala de aula, intensidade da voz e presença de alteração vocal em professores. MÉTODOS: Foi realizada medição do ruído ambiental em dez salas de escolas municipais de ensino fundamental. A intensidade das vozes das professoras foi medida durante atividade de ensino. Amostras de vogal prolongada [é] e contagem de 1 a 20 emitidas pelas professoras foram analisadas utilizando escala GRBASI. Os resultados obtidos foram correlacionados. RESULTADOS: A média de ruído ambiental sem a presença das crianças em sala de aula variou de 40 a 51 dB(A e com a presença das crianças de 45 a 65 dB(A. Entre as professoras, houve 70% de ocorrência de vozes alteradas no grau geral (G e 90% com tensão na voz (S, variando entre graus discreto e moderado. Constatou-se variação entre 52 dB(A e 68 dB(A na intensidade da voz das professoras, atingindo 7,48 dB(A acima do nível do ruído ambiental. Houve correlação entre a intensidade vocal das professoras e ruído ambiental na presença das crianças durante a aula. CONCLUSÃO: Os níveis de ruído ambiental em sala de aula são altos e se correlacionam com o aumento da intensidade das vozes das professoras. Embora com alta ocorrência de vozes alteradas, não é possível correlacioná-las com o nível de ruído ambiental.PURPOSE: To explore the existence of correlations between environmental noise in classrooms, voice intensity and teacher's vocal problems. METHODS: Environmental noise was measured in 10 classrooms of municipal elementary schools; the intensity of teachers' voice was measured during teaching practice; teachers' speech samples containing emissions of sustained vowel [é] and counting from 1 to 20 were analyzed using the GRBASI protocol; and the results were tested for correlation. RESULTS: The average of environmental noise varied from 40 to 51 dB(A without the presence of children in the classroom, and

  18. Correlação entre ansiedade e anéis de tensão Correlación entre ansiedad y anillos nerviosos Anxiety and contraction furrows correlations

    Directory of Open Access Journals (Sweden)

    Leia Fortes Salles

    2011-03-01

    integrantes del Grupo de Estudios en Prácticas Alternativas y Complementarias de Salud de la Escuela de Enfermería de la Universidad de São Paulo. Hubo correspondencia entre el iris y el inventario en 75% de la población y el coeficiente de correlación de Spearman destacó una correlación positiva y significativa entre los resultados del IDARE con la cantidad y la clasificación de los anillos nerviosos. Este resultado sugiere que la presencia de estas señales en el iris indica una predisposición más importante para la ansiedad.In psychosomatic and psychoneuroimmunological studies there is growing interest in anxiety as a factor that predisposes individuals to numerous diseases. This suggests that reducing anxiety behaviors would be beneficial to an individual’s health. Evaluation of the iris permits professionals to determine certain personality characteristics of the individual. Contraction furrows are one of the signs studied in iridology and they are related to anxiety. The purpose of this study is to verify the correlation of contraction furrows analysis with the IDATE anxiety inventory results. Data collection was performed between september and october 2008, with 20 members of the National Council for Scientific and Technological Development Study Group for Alternative and Complementary Health Practices at University of Sao Paulo School of Nursing. A correlation of 75% was found between the iris analysis and the inventory. Spearman’s correlation coefficient showed a positive and statistically significant correlation between IDATE scores and the quantity and classification of contraction furrows. These results suggest that the presence of these signs indicates a greater predisposition to anxiety behaviors.

  19. Density and surface tension of melts of zirconium and hafnium fluorides with lithium fluoride

    International Nuclear Information System (INIS)

    Katyshev, S.F.; Artemov, V.V.; Desyatnik, V.N.

    1988-01-01

    A study was conducted to determine the temperature dependence of the density and surface tension of melts of LiF-ZrF 4 and LiF-HfF 4 . Density and surface tension were determined by the method of maximum pressure in an argon bubble. On the basis of experimental data over the entire concentration range the molar volumes and their relative deviations from the additive molar volumes were calculated for 1100 0 K. The positive deviations of the molar volumes from additivity in the LiF-HfF 4 system (22.45%) were greater than in the LiF-ZrF 4 system (15.75%). This indicated that the reaction with lithium fluoride is intensified with the switch to the hafnium fluoride. Results also demonstrated that the fluorides are surface-active components in the molten mixtures

  20. An Auger electron spectroscopy study on the anodization process of high-quality thin-film capacitors made of hafnium

    International Nuclear Information System (INIS)

    Noya, Atsushi; Sasaki, Katsutaka; Umezawa, Toshiji

    1989-01-01

    Formation process of the anodic oxide film of hafnium for use as a thin-film capacitor has been examined by the current-voltage characteristics of the anodization and the in-depth analysis of formed oxide using Auger electron spectroscopy. It is found that the oxide growth obeys three different rate laws such as the linear rate law at first and next the parabolic rate law during the constant current anodization, and then the reciprocal logarithmic rate law during the constant voltage anodization following after the constant current process. From the Auger electron spectroscopy analysis, it is found that the shape of the compositional depth profile of the grown oxide film varies associating with the rate law of oxidation obeyed. The variation of depth profile correlating with the rate law is discussed with respect to each elementary process such as the transport and/or the reaction of chemical species interpreted from the over-all behavior of anodization process. It is revealed that the stoichiometric film having an interface with sharp transition, which is favorable for obtaining excellent electrical properties of the capacitor, can be obtained under the condition that the phase-boundary reaction is the rate-determining step of the anodization. The constant voltage anodization process also satisfies such circumstances and therefore can be favorable method for preparing highquality thin-film capacitors. (author)

  1. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    Science.gov (United States)

    Mora, M.; Vera, E.; Aperador, W.

    2016-02-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers.

  2. Tribo-electrochemical characterization of hafnium multilayer systems deposited on nitride/vanadium nitride AISI 4140 steel

    International Nuclear Information System (INIS)

    Mora, M; Vera, E; Aperador, W

    2016-01-01

    In this work is presented the synergistic behaviour among corrosion/wear (tribocorrosion) of the multilayer coatings hafnium nitride/vanadium nitride [HfN/VN]n. The multilayers were deposited on AISI 4140 steel using the technique of physical vapor deposition PVD magnetron sputtering, the tests were performed using a pin-on-disk tribometer, which has an adapted potentiostat galvanostat with three-electrode electrochemical cell. Tribocorrosive parameters such as: Friction coefficient between the coating and the counter body (100 Cr6 steel ball); Polarization resistance by means of electrochemical impedance spectroscopy technique and corrosion rate by polarization curves were determined. It was observed an increase in the polarization resistance, a decrease in the corrosion rate and a low coefficient of friction in comparison with the substrate, due to an increase on the number of bilayers. (paper)

  3. Rapid screening of nuclear grade zirconium silicate without separation of hafnium from the bulk matrix

    International Nuclear Information System (INIS)

    Venkatesh, Manisha; Sharma, P.K.; Avhad, D.K.; Basu, H.; Singhal, R.K.; Reddy, A.V.R.

    2014-01-01

    Zirconium silicate, also zirconium orthosilicate, (ZrSiO 4 ) is a chemical compound, and occurs in nature as zircon, a silicate mineral. The concentration of Hafnium in nuclear grade Zirconium must be less than 0.2% w/w of Zr. In view of this it must be accurately chemically characterized before issuing a certification for export under non nuclear category. As the chemistry of Zr and Hf is similar, it is difficult to separate Hf by direct wet chemical method. During this work, concentration of Hf in zirconium silicate was measured by Field Portable X-ray Fluorescence (FPXRF) and results obtained were validated by using detailed chemical method. FPXRF spectrometry has become a common analytical technique for on-site screening and fast turnaround analysis of contaminant elements in environmental samples

  4. Hafnium Films and Magnetic Shielding for TIME, A mm-Wavelength Spectrometer Array

    Science.gov (United States)

    Hunacek, J.; Bock, J.; Bradford, C. M.; Butler, V.; Chang, T.-C.; Cheng, Y.-T.; Cooray, A.; Crites, A.; Frez, C.; Hailey-Dunsheath, S.; Hoscheit, B.; Kim, D. W.; Li, C.-T.; Marrone, D.; Moncelsi, L.; Shirokoff, E.; Steinbach, B.; Sun, G.; Trumper, I.; Turner, A.; Uzgil, B.; Weber, A.; Zemcov, M.

    2018-04-01

    TIME is a mm-wavelength grating spectrometer array that will map fluctuations of the 157.7-μm emission line of singly ionized carbon ([CII]) during the epoch of reionization (redshift z ˜ 5-9). Sixty transition-edge sensor (TES) bolometers populate the output arc of each of the 32 spectrometers, for a total of 1920 detectors. Each bolometer consists of gold absorber on a ˜ 3 × 3 mm silicon nitride micro-mesh suspended near the corners by 1 × 1 × 500 μm silicon nitride legs targeting a photon-noise-dominated NEP ˜ 1 × 10^{-17} W/√{Hz} . Hafnium films are explored as a lower-T_c alternative to Ti (500 mK) for TIME TESs, allowing thicker support legs for improved yield. Hf T_c is shown to vary between 250 and 450 mK when varying the resident Ar pressure during deposition. Magnetic shielding designs and simulations are presented for the TIME first-stage SQUIDs. Total axial field suppression is predicted to be 5 × 10^7.

  5. Correlación entre las edades cronológica y ósea en pacientes de ortodoncia Correlation between the chronological and bone ages in orthodontics patients

    Directory of Open Access Journals (Sweden)

    Gladia Toledo Mayarí

    2011-03-01

    Full Text Available Nos propusimos determinar la edad ósea según sexo y edad cronológica e identificar la relación existente entre las edades cronológica y ósea, en los pacientes estudiados. Se realizó un estudio descriptivo y transversal en un universo constituido por todos los niños y adolescentes tributarios de tratamiento ortodóncico, que ingresaron en la Clínica de Ortodoncia de la Facultad de Estomatología de la Universidad de Ciencias Médicas de La Habana, en el periodo de enero de 2004 a diciembre de 2006. El grupo etáreo se encontraba entre 8 y 16 años, de donde se seleccionó una muestra de 150 pacientes, mediante un muestreo por cuotas. A cada paciente se le realizó una radiografía de la mano izquierda, donde se determinó la edad ósea, a través del método de Tanner-Whitehouse 2 (TW2 y se calculó la correlación entre la edad ósea y la cronológica a través del coeficiente de correlación lineal de Pearson. Se encontraron correlaciones altas muy significativas entre las edades cronológica y ósea, en ambos sexos; sexo femenino r= 0,977 y masculino r= 0,983 (pTo determine the bone age according to the sex and chronologic age and to identify the relation between the chronologic and bone ages in study patients. A cross-sectional and descriptive study was conducted in a universe including all children and adolescents needing orthodontics treatment admitted in the Orthodontics Clinic of the Stomatology Faculty of the Higher Institute of Medical Sciences (HIMS-Habana from January, 2004 to December, 2006 aged between 8 and 16 selecting a sample including 150 patients by admission sampling, each patient undergoes a left hand radiography to determine the bone age by Tanner-Whitehouse 2 method (TW2 estimating the correlation between the bone age and chronologic one trough Pearson linear correlation coefficient. There were high and very significant correlations between the bone ages and the chronologic one in both sexes, female sex r= 0

  6. A spanish mineral of zirconium and hafnium. Separation of the two elements by liquid-liquid extraction, using tributyl phosphate as chelating agent

    International Nuclear Information System (INIS)

    Ruiz Sanchez, F.; Cruz Castillo, F. de la; Fernandez Cellini, R.

    1962-01-01

    The zirconium and Hafnium oxides are obtained from a Spanish mineral of zircon with an average contest of 55% in ZrO 2 -HfO 2 . An alkaline fusion to open the mineral, followed by a purification by crystallization as (Zr O-Hf O)Cl 2 H 2 O or as (Zr-Hf) (SO 4 ) 2 . 4H 2 O, is used. A discussion of the best experimental conditions for opening the mineral and of the purification method is made. (Author) 45 refs

  7. George de Hevesy (1885-1966). Discoverer of hafnium, founder of radioanalytical chemistry and X-ray fluorescence analysis and father of nuclear medicine

    International Nuclear Information System (INIS)

    Niese, Siegfried

    2017-01-01

    George de Hevesy known as discoverer of hafnium, founder of radioanalytical chemistry and X-ray fluorescence analysis and father of nuclear medicine has done important research work in inorganic, physical and radioanalytical and physiological chemistry as well as in geochemistry, radiation biology and medicine. When he must flee for political reasons from a country he must change his colleagues, his equipments, and the topic of his work. It is extremely surprising that he could receive important results under such circumstances even at an advanced age. (author)

  8. Silicon-doped hafnium oxide anti-ferroelectric thin films for energy storage

    Science.gov (United States)

    Ali, Faizan; Liu, Xiaohua; Zhou, Dayu; Yang, Xirui; Xu, Jin; Schenk, Tony; Müller, Johannes; Schroeder, Uwe; Cao, Fei; Dong, Xianlin

    2017-10-01

    Motivated by the development of ultracompact electronic devices as miniaturized energy autonomous systems, great research efforts have been expended in recent years to develop various types of nano-structural energy storage components. The electrostatic capacitors characterized by high power density are competitive; however, their implementation in practical devices is limited by the low intrinsic energy storage density (ESD) of linear dielectrics like Al2O3. In this work, a detailed experimental investigation of energy storage properties is presented for 10 nm thick silicon-doped hafnium oxide anti-ferroelectric thin films. Owing to high field induced polarization and slim double hysteresis, an extremely large ESD value of 61.2 J/cm3 is achieved at 4.5 MV/cm with a high efficiency of ˜65%. In addition, the ESD and the efficiency exhibit robust thermal stability in 210-400 K temperature range and an excellent endurance up to 109 times of charge/discharge cycling at a very high electric field of 4.0 MV/cm. The superior energy storage performance together with mature technology of integration into 3-D arrays suggests great promise for this recently discovered anti-ferroelectric material to replace the currently adopted Al2O3 in fabrication of nano-structural supercapacitors.

  9. Tuning the magnetic properties of pure hafnium by high pressure torsion

    International Nuclear Information System (INIS)

    Cepeda-Jiménez, C.M.; Beltrán, J.I.; Hernando, A.; García, M.A.; Ynduráin, F.; Zhilyaev, A.; Pérez-Prado, M.T.

    2017-01-01

    This work demonstrates that room temperature (RT) ferromagnetism might be triggered in pure hafnium (Hf), a classic paramagnet, by severe plastic deformation (SPD) via high pressure torsion (HPT). The origin of this phenomenon is elucidated by a combined approach including density functional theory (DFT) calculations and transmission electron microscopy (TEM). In particular, it is shown that the elastic lattice distorsions induced in pure Hf as a consequence of grain refinement down to the nanocrystalline regime by HPT lead to the development of a new monoclinic crystalline structure that exhibits a spontaneous magnetization at RT. DFT calculations are utilized to prove that local stretching of the original pure Hf hexagonal close packed (hcp) lattice along specific pyramidal directions, due to the presence of internal stresses in the deformed nanostructure, may give rise to the emergence of the monoclinic phase, which is endowed with a net magnetic moment. An excellent agreement is found between DFT calculations and experimental TEM observations, which provide a first evidence of the presence of the pure Hf monoclinic crystal lattice. This work shows that SPD may constitute a viable, yet widely unexplored, strategy to tune the magnetic properties and, in particular, to induce RT ferromagnetism in bulk non-magnetic metals.

  10. Characterization of hafnium oxide resistive memory layers deposited on copper by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, B.D.; Bishop, S.M. [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States); Leedy, K.D. [Air Force Research Laboratory, 2241 Avionics Circle, Wright Patterson Air Force Base, Dayton, OH 45433 (United States); Cady, N.C., E-mail: ncady@albany.edu [SUNY College of Nanoscale Science and Engineering, 255 Fuller Road, Albany, NY 12203 (United States)

    2014-07-01

    Hafnium oxide-based resistive memory devices have been fabricated on copper bottom electrodes. The HfO{sub x} active layers in these devices were deposited by atomic layer deposition (ALD) at 250 °C with tetrakis(dimethylamido)hafnium(IV) as the metal precursor and an O{sub 2} plasma as the reactant. Depth profiles of the HfO{sub x} by X-ray photoelectron spectroscopy and secondary ion mass spectroscopy revealed a copper concentration on the order of five atomic percent throughout the HfO{sub x} film. In addition to the Cu doped HfO{sub x}, a thin layer (20 nm) of Cu{sub x}O is present at the surface. This surface layer is believed to have formed during the ALD process, and greatly complicates the analysis of the switching mechanism. The resistive memory structures fabricated from the ALD HfO{sub x} exhibited non-polar resistive switching, independent of the top metal electrode (Ni, Pt, Al, Au). Resistive switching current voltage (I–V) curves were analyzed using Schottky emission and ionic hopping models to gain insight into the physical mechanisms underpinning the device behavior. During the forming process it was determined that, at voltages in excess of 2.5 V, an ionic hopping model is in good agreement with the I–V data. The extracted ion hopping distance ∼ 4 Å was within the range of interatomic spacing of HfO{sub 2} during the forming process consistent with ionic motion of Cu{sup 2+} ions. Lastly the on state I–V data was dominated at larger voltages by Schottky emission with an estimated barrier height of ∼ 0.5 eV and a refractive index of 2.59. The consequence of the Schottky emission analysis indicates the on state resistance to be a product of a Pt/Cu{sub 2}O/Cu filament(s)/Cu{sub 2}O/Cu structure. - Highlights: • HfO{sub 2} was grown via atomic layer deposition at 250 and 100 °C on Cu substrates. • A Cu{sub 2}O surface layer and Cu doping were observed in post-deposition of HfO{sub 2}. • Resistive memory devices were fabricated and

  11. Thermodynamic and kinetic studies in the systems alkali chloride-zinconium (or hafnium) tetrachloride: Part I. Vapour pressure measurements over hexachloro compounds and use of vapour pressure data in fractional decomposition

    International Nuclear Information System (INIS)

    Ray, H.S.; Bhat, B.G.; Reddy, G.S.; Biswas, A.K.

    1978-01-01

    A molten tin isoteniscope has been used to measure the vapour pressures over ZrCl 4 , HfCl 4 and the hexachlore zirconates (M 2 ZrCl 6 ) and the hexachloro hafnates (M 2 HfCl 6 ) of four alkali metals (M = Na,K,Rb,Cs). The method of preparation of these compounds and the effect of small amounts of residual alkali chlorides on the their vapour pressure are discussed. The pressure-temperature plots are examined in the light of some theoretical postulates. A scheme for separation of hafnium from zirconoium by multistage fractional decomposition of the hexachlore compounds of any alkali metal is described. The scheme, which is analogous to rectification in liquid-vapour systems, employs a countercurrent flow of Zr(Hf)Cl 4 in a gas stream and a moving bed of alkali chlorides. The separation is based on the difference in the dissociation equilibrium for zirconium and hafnium compounds. Stage calculations for such a scheme and the main conclusions of a computational work are presented. (author)

  12. Design of an Extractive Distillation Column for the Environmentally Benign Separation of Zirconium and Hafnium Tetrachloride for Nuclear Power Reactor Applications

    Directory of Open Access Journals (Sweden)

    Le Quang Minh

    2015-09-01

    Full Text Available Nuclear power with strengthened safety regulations continues to be used as an important resource in the world for managing atmospheric greenhouse gases and associated climate change. This study examined the environmentally benign separation of zirconium tetrachloride (ZrCl4 and hafnium tetrachloride (HfCl4 for nuclear power reactor applications through extractive distillation using a NaCl-KCl molten salt mixture. The vapor–liquid equilibrium behavior of ZrCl4 and HfCl4 over the molten salt system was correlated with Raoult’s law. The molten salt-based extractive distillation column was designed optimally using a rigorous commercial simulator for the feasible separation of ZrCl4 and HfCl4. The molten salt-based extractive distillation approach has many potential advantages for the commercial separation of ZrCl4 and HfCl4 compared to the conventional distillation because of its milder temperatures and pressure conditions, smaller number of required separation trays in the column, and lower energy requirement for separation, while still taking the advantage of environmentally benign feature by distillation. A heat-pump-assisted configuration was also explored to improve the energy efficiency of the extractive distillation process. The proposed enhanced configuration reduced the energy requirement drastically. Extractive distillation can be a promising option competing with the existing extraction-based separation process for zirconium purification for nuclear power reactor applications.

  13. Metallorganic chemical vapor deposition and atomic layer deposition approaches for the growth of hafnium-based thin films from dialkylamide precursors for advanced CMOS gate stack applications

    Science.gov (United States)

    Consiglio, Steven P.

    To continue the rapid progress of the semiconductor industry as described by Moore's Law, the feasibility of new material systems for front end of the line (FEOL) process technologies needs to be investigated, since the currently employed polysilicon/SiO2-based transistor system is reaching its fundamental scaling limits. Revolutionary breakthroughs in complementary-metal-oxide-semiconductor (CMOS) technology were recently announced by Intel Corporation and International Business Machines Corporation (IBM), with both organizations revealing significant progress in the implementation of hafnium-based high-k dielectrics along with metal gates. This announcement was heralded by Gordon Moore as "...the biggest change in transistor technology since the introduction of polysilicon gate MOS transistors in the late 1960s." Accordingly, the study described herein focuses on the growth of Hf-based dielectrics and Hf-based metal gates using chemical vapor-based deposition methods, specifically metallorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD). A family of Hf source complexes that has received much attention recently due to their desirable properties for implementation in wafer scale manufacturing is the Hf dialkylamide precursors. These precursors are room temperature liquids and possess sufficient volatility and desirable decomposition characteristics for both MOCVD and ALD processing. Another benefit of using these sources is the existence of chemically compatible Si dialkylamide sources as co-precursors for use in Hf silicate growth. The first part of this study investigates properties of MOCVD-deposited HfO2 and HfSixOy using dimethylamido Hf and Si precursor sources using a customized MOCVD reactor. The second part of this study involves a study of wet and dry surface pre-treatments for ALD growth of HfO2 using tetrakis(ethylmethylamido)hafnium in a wafer scale manufacturing environment. The third part of this study is an investigation of

  14. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface

    Science.gov (United States)

    Nguyen, Duc; Mallek, Justin; Cloud, Andrew N.; Abelson, John R.; Girolami, Gregory S.; Lyding, Joseph; Gruebele, Martin

    2014-11-01

    Direct visualization of the dynamics of structural glasses and amorphous solids on the sub-nanometer scale provides rich information unavailable from bulk or conventional single molecule techniques. We study the surface of hafnium diboride, a conductive ultrahigh temperature ceramic material that can be grown in amorphous films. Our scanning tunneling movies have a second-to-hour dynamic range and single-point current measurements extend that to the millisecond-to-minute time scale. On the a-HfB2 glass surface, two-state hopping of 1-2 nm diameter cooperatively rearranging regions or "clusters" occurs from sub-milliseconds to hours. We characterize individual clusters in detail through high-resolution (single cluster vertical displacements, we can reconstruct the local free energy landscape of individual clusters, complete with activation barrier height, a reaction coordinate in nanometers, and the shape of the free energy landscape basins between which hopping occurs. The experimental images are consistent with the compact shape of α-relaxors predicted by random first order transition theory, whereas the rapid hopping rate, even taking less confined motion at the surface into account, is consistent with β-relaxations. We make a proposal of how "mixed" features can show up in surface dynamics of glasses.

  15. Estudo correlacional entre o Teste de Pfister e o Desenho da Figura Humana Correlational study between the Test of Pfister and the Human Figure Drawing

    Directory of Open Access Journals (Sweden)

    Lucila Moraes Cardoso

    2006-12-01

    Full Text Available Este estudo teve como objetivo buscar as correlações existentes entre os indicadores emocionais e cognitivos das Pirâmides Coloridas de Pfister e do Desenho da Figura Humana, tanto no sistema DFH-Koppitz como no DFH-Sisto. As técnicas das Pirâmides Coloridas de Pfister (TPC e do Desenho da Figura Humana (DFH são instrumentos projetivos que permitem que se conheçam aspectos da personalidade de quem os executa. De acordo com a literatura, os dois métodos medem o mesmo construto, justificando o objetivo do presente estudo. Neste estudo, foram considerados os protocolos do TPC e do DFH de 118 meninos e meninas com idade entre 6 e 12 anos, estudantes do pré à sexta série e nível socioeconômico variado. Os testes foram aplicados em uma única sessão individual, com tempo livre. Utilizou-se o SPSS para estabelecer a relação entre os dois instrumentos. As análises empregadas possibilitaram verificar algumas relações entre os indicadores emocionais e cognitivos dos dois testes.The present study was aimed at seeking correlations between the emotional and cognitive indicators of the Colored Pyramids Test of Pfister (CPT and the Human Figure Drawing (HFD - both in the Koppitz's HFD and the Sisto's HFD systems. The techniques of Colored Pyramids Test (CPT of Pfister and Human Figure Drawing (HFD are projective instruments that permit to know aspects of the executor's personality. According to literature, the two methods measure the same constructo, justifying the objective of looking for correlations between them. The protocols of both CPT and HFD of 118 boys and girls aged between 6 and 12, students from elementary to sixth-grade classes and belonging to different social-economic levels, were considered at the present study. Tests were applied in a single individual session, with free time. The SPSS program was used in order to establish relation between both instruments. The analyses employed allowed to check some relations between

  16. About the structure and stability of complex carbonates of thorium (IV), cerium (IV), zirconium (IV), hafnium (IV)

    International Nuclear Information System (INIS)

    Dervin, Jacqueline

    1972-01-01

    This research thesis addressed the study of complex carbonates of cations of metals belonging to the IV A column, i.e. thorium (IV), zirconium (IV), hafnium (IV), and also cerium (IV) and uranium (VI), and more particularly focused on ionic compounds formed in solution, and also on the influence of concentration and nature of cations on stability and nature of the formed solid. The author first presents methods used in this study, discusses their precision and scope of validity. She reports the study of the formation of different complex ions which have been highlighted in solution, and the determination of their formation constants. She reports the preparation and study of the stability domain of solid complexes. The next part reports the use of thermogravimetric analysis, IR spectrometry, and crystallography for the structural study of these compounds

  17. Análise da correlação entre limiares auditivos, questionários validados e medidas psicoacústicas em pacientes com zumbido Correlation analysis of hearing thresholds, validated questionnaires and psychoacoustic measurements in tinnitus patients

    Directory of Open Access Journals (Sweden)

    Ricardo Rodrigues Figueiredo

    2010-08-01

    Full Text Available Uma das principais dificuldades nos estudos clínicos sobre zumbido reside na falta de consenso sobre os métodos de mensuração. OBJETIVO: Avaliar a correlação entre os limiares audiométricos, pitch matching (PM, minimum masking level (MML, Tinnitus Handicap Inventory (THI e o Inventário de Depressão de Beck (BDI em pacientes com zumbido. MODELO DE ESTUDO: Prospectivo, coorte transversal. MATERIAL E MÉTODO: 48 pacientes com zumbido como queixa principal foram submetidos aos testes audiométricos e questionários acima descritos. Os dados foram comparados estatisticamente para as correlações entre os métodos. RESULTADOS: Não houve correlação estatisticamente significativa entre o THI e MML, tanto em pacientes com BDI acima e abaixo de 14 pontos, bem como entre a frequência de pior limiar auditivo e o Pitch matching e entre a frequência de "cut-off" e o PM nos pacientes com curvas descendentes em rampa. CONCLUSÕES: Não existe correlação estatisticamente significativa entre as medidas psicoacústicas do zumbido, os limiares audiométricos e os questionários de avaliação. O zumbido é um sintoma muito complexo e avaliações isoladas pelos métodos acima não são satisfatórias.One of the most criticized points in tinnitus clinical studies arise from the lack of consensus about measurement methods. AIM: To evaluate the correlation between audiometric thresholds, pitch matching (PM, minimum masking level (MML, Tinnitus Handicap Inventory (THI and the Beck Depression Inventory (BDI in tinnitus patients. STUDY DESIGN: Prospective, cross-sectional. MATERIALS AND METHODS: Subjects were submitted to tonal audiometry, PM and MML for tinnitus. They also filled out the THI and BDI. Data was statistically compared for correlation purposes between audiometric thresholds, psycho-acoustic measures and questionnaires. RESULTS: There was no statistically significant correlation between THI and MML, both in patients with BDI scores under and

  18. Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study

    International Nuclear Information System (INIS)

    Davis, Linda L.; Darab, John G.; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S.; Li, Hong; Strachan, Denis M.; Li, Liyu

    2003-01-01

    A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others

  19. Entre/Plantas

    OpenAIRE

    Montoro Coso, Ricardo; Sonntag, Franca Alexandra

    2014-01-01

    La palabra Inter-és proviene etimológicamente de las palabras latinas inter y esse; y significa “lo que está-entre dos o más personas, o sea lo que las une pero también las separa”. Los prefijos inter- y entre-, en la mayor parte de los casos, describen estados o acciones ambiguas de los términos que preceden. De esta operación aditiva surgen maclas de vocablos; el inter-sticio como la “hendidura o espacio que media entre dos cuerpos o entre dos partes de un mismo cuerpo”; y así sucesivamente...

  20. Correlação fenotípica entre caracteres de híbridos diploides (AA de bananeira Phenotypic correlation between characters in banana (AA diploid hybrids

    Directory of Open Access Journals (Sweden)

    Lauro Saraiva Lessa

    2012-12-01

    Full Text Available O estudo de correlação tem como propósito mensurar a alteração em um caráter quando se altera outro. Neste trabalho, objetivou-se estimar correlações fenotípicas entre o número de frutos por cacho e 22 caracteres avaliados em híbridos diploides (AA de bananeira. No experimento, conduzido na Embrapa Mandioca e Fruticultura, em blocos casualizados com quatro repetições, foram avaliados 11 híbridos diploides (AA de bananeira. Os caracteres avaliados foram: altura de plantas, diâmetro do pseudocaule, número de filhos, número de folhas na floração, período do plantio ao florescimento, presença de pólen, peso do cacho e da ráquis, sigatoka-amarela no florescimento, número de folhas na colheita, Sigatoka-amarela na colheita do cacho, número de dias do florescimento à colheita, comprimento e diâmetro do engaço, peso da segunda penca, número de pencas e de frutos por cacho, fragilidade do pedicelo, comprimento e diâmetro do fruto e comprimento do pedicelo, além de presença de semente. Após a tabulação, procederam-se a estudos de correlação entre o número de frutos e os demais caracteres da planta. Essas correlações variaram entre os genótipos, sendo assim, observado que as associações entre o número de frutos e os caracteres vegetativos da planta foram, de forma geral, não significativas. Já as relações entre o número de frutos por cacho e os outros caracteres produtivos foram, predominantemente, significativas.The objective of the present study was to estimate the phenotypic correlations between the number of fruits per bunch and 22 characters evaluated in banana (AA diploid hybrids. The experiment was carried out at Embrapa Cassava and Fruits in randomized blocks with four repetitions and 11 (AA banana diploid hybrids were evaluated. The following characteristics were evaluated: plant height, pseudostem diameter, number of suckers, number of leaves during flowering, plant cycle until emission of the

  1. Correlação entre os teores de líber e fibras em caules de crotalária e malva Correlation between bast and fiber content in sunn hemp and malva stalks

    Directory of Open Access Journals (Sweden)

    Anísio Azzini

    1986-01-01

    Full Text Available No presente estudo, estimou-se a correlação entre os teores de líber (casca e fibras em caules de crotalária (Crotalaria juncea L. e malva (Urena lobata L., com o objetivo de estabelecer um procedimento simples e rápido de análise de fibra. Os resultados obtidos mostraram que os teores de líber e fibra estão relacionados entre si, com alto nível de significância (p > 0,99 para as correlações entre essas duas características tecnológicas. Os coeficientes de correlação observados, de 0,84 e 0,79, respectivamente, para crotalária e malva, permitem a avaliação indireta do teor de fibra liberiana através do teor de líber, estabelecendo um procedimento simples e rápido de análise de fibra, a ser utilizado especificamente em programas de melhoramento genético.In this paper it was estimated the correlation between the bast and fiber contents in suns hemp (Crotalaria juncea L. and malva (Urena lobata L. stalks. The results showed that fiber contents are related with a high level of signification (p > 0.99 for the correlation between these two technological characteristics. The correlation coefficients observed were of 0.84 and 0.79, respectively to sunn hemp and malva. These high levels of correlation showed that the fiber content may be evaluated indirectly through the bast content, establishing a simple and rapid procedure for fiber determination of both species.

  2. A search for long-lived radionuclides produced by fast-neutron irradiations of copper, silver, europium, terbium, and hafnium

    International Nuclear Information System (INIS)

    Meadows, J.W.; Smith, D.L.; Ikeda, Y.; Konno, C.

    1990-01-01

    Identical sample packets, each containing samples of elemental copper, silver, europium, terbium, and hafnium, as well as titanium, iron and nickel as dosimeters, have been irradiated in three distinct accelerator neutron fields (at Argonne National Laboratory and Los Alamos National Laboratory in the U.S.A., and Japan Atomic Energy Research Institute, Tokai, Japan) as part of an interlaboratory research collaboration to search for the production of long-lived radionuclides for fusion waste disposal applications. This paper is a progress report on this project. To date, we have detected the following activities, and have obtained preliminary experimental cross section values for several of these: Ag-106m,108m,110m; Eu-150m,152g,154; Tb-158,160; and Hf-175,178m2,179m2,181. (author). 11 refs, 1 fig., 4 tabs

  3. Correlación entre ondas de ensayo para dispositivos supresores de sobretensiones Correlation factor between standard surge waves for testing transient overvoltage suppressor devices

    Directory of Open Access Journals (Sweden)

    Julio Guillermo Zola

    2008-06-01

    Full Text Available Existe un variado número de ondas impulsivas estándar que se utilizan para ensayar el funcionamiento de los dispositivos supresores de sobretensiones transitorias. En particular, resultan de importancia los ensayos que comprueban la corriente máxima de impulso de descarga. Se analiza en este trabajo la relación existente entre estas distintas formas de ondas impulsivas, de forma tal de poder obtener una correlación entre ellas para aplicar una u otra con similares resultados. Las conclusiones que se alcanzan a partir de un desarrollo teórico simplificado son corroboradas mediante medición en laboratorio y simulación.A wide number of standard surge waves current for testing the behavior of transient overvoltage suppressor devices are currently being used. The value of pick surge current is one of the most important tests. The ratio between the surge waves to obtain a correlation factor between them, so they can be applied to get equivalent results is analyzed in this paper. The theoretical conclusions are verified by simulation and laboratory measurements.

  4. Ferroelectric transistors with monolayer molybdenum disulfide and ultra-thin aluminum-doped hafnium oxide

    Science.gov (United States)

    Yap, Wui Chung; Jiang, Hao; Liu, Jialun; Xia, Qiangfei; Zhu, Wenjuan

    2017-07-01

    In this letter, we demonstrate ferroelectric memory devices with monolayer molybdenum disulfide (MoS2) as the channel material and aluminum (Al)-doped hafnium oxide (HfO2) as the ferroelectric gate dielectric. Metal-ferroelectric-metal capacitors with 16 nm thick Al-doped HfO2 are fabricated, and a remnant polarization of 3 μC/cm2 under a program/erase voltage of 5 V is observed. The capability of potential 10 years data retention was estimated using extrapolation of the experimental data. Ferroelectric transistors based on embedded ferroelectric HfO2 and MoS2 grown by chemical vapor deposition are fabricated. Clockwise hysteresis is observed at low program/erase voltages due to slow bulk traps located near the 2D/dielectric interface, while counterclockwise hysteresis is observed at high program/erase voltages due to ferroelectric polarization. In addition, the endurances of the devices are tested, and the effects associated with ferroelectric materials, such as the wake-up effect and polarization fatigue, are observed. Reliable writing/reading in MoS2/Al-doped HfO2 ferroelectric transistors over 2 × 104 cycles is achieved. This research can potentially lead to advances of two-dimensional (2D) materials in low-power logic and memory applications.

  5. Correlações entre caracteres da planta e do cacho em bananeira (Musa spp Correlations among characters of the plant and of the bunch in banana (Musa spp.

    Directory of Open Access Journals (Sweden)

    Sérgio Luiz Rodrigues Donato

    2006-02-01

    Full Text Available Os caracteres observados em áreas experimentais têm natureza fenotípica e suas correlações são estimadas visando mensurar alterações em um caráter quando se altera outro relacionado. Objetivou-se com este trabalho, quantificar a relação entre os caracteres da planta e do cacho observados na época do florescimento e da colheita de 13 genótipos (variedades e híbridos de bananeira (Musa spp., em dois ciclos de produção, em Guanambi, Bahia. Foram utilizadas as variedades Prata anã, Pacovan (AAB, Grande naine e Nanicão (AAA, e os híbridos PA42-44, PV42-85, PV42-142, PV42-68 e ST12-31 (AAAB e Ambrosia, Calipso, Bucaneiro e FHIA02 (AAAA, selecionados na Embrapa Mandioca e Fruticultura. Consideraram-se os caracteres: altura da planta; perímetro do pseudocaule; número de folhas vivas no florescimento e na colheita; número de dias do plantio ao florescimento e à colheita; intervalo florescimento à colheita; peso do cacho, da ráquis e da pencas; comprimento e diâmetro do engaço; número de pencas e de frutos; peso da segunda penca; peso, comprimento e diâmetro do fruto e espessura da casca. As correlações entre o peso do cacho e os demais caracteres estudados, variaram entre genótipos e ciclos. As associações entre o peso do cacho e os caracteres da planta, de forma geral foram não-significativas, e entre o peso do cacho e os caracteres do cacho significativas e positivas para a maioria dos genótipos, nos ciclos avaliados. As correlações entre os caracteres envolvendo todos os genótipos ao longo dos dois ciclos foram predominantemente positivas e não- significativas, entretanto, as associações entre os caracteres do cacho foram em maioria significativas, positivas e com valores expressivos.The characters observed in a experimental areas has phenotypic nature and their correlations are estimated with the purpose to verify alterations in one character when is altered another. The objectives of this work were to

  6. Studies of metal binding by the iron transport protein transferrin using time differential perturbed angular correlation spectroscopy

    International Nuclear Information System (INIS)

    Then, G.M.

    1987-01-01

    The binding of the transition metal hafnium to transferrin was studied under various chemical conditions using time differential perturbed γγ angular correlation spectroscopy (TDPAC). Observing the electric quadrupole interaction of the 181 Hf probe nuclei size and symmetry of the electric field gradient induced by the ligands of the metal ions can be determined. The experimental data suggest how homogeneous the binding conditions are and to which extend relaxation phenomena are involved. Due to the excellent time resolution obtained with new BaF 2 detectors the quadrupole coupling parameters of 181 Hf-transferrin could be determined very accurately. Under nearly physiological conditions different binding configurations were quantitatively characterized by spectroscopic means and distinguished with high specificity. (orig./PW) [de

  7. IER-297 CED-2: Final Design for Thermal/Epithermal eXperiments with Jemima Plates with Polyethylene and Hafnium

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, A. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Zywiec, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-01-11

    This report presents the final design (CED-2) for IER-297, and focuses on 15 critical configurations using highly enriched uranium (HEU) Jemima plates moderated by polyethylene with and without hafnium diluent. The goal of the U.S. Nuclear Criticality Safety Program’s Thermal/Epithermal eXperiments (TEX) is to design and conduct new critical experiments to address high priority nuclear data needs from the nuclear criticality safety and nuclear data communities, with special emphasis on intermediate energy (0.625 eV – 100 keV) assemblies that can be easily modified to include various high priority diluent materials. The TEX (IER 184) CED-1 Report [1], completed in 2012, demonstrated the feasibility of meeting the TEX goals with two existing NCSP fissile assets, plutonium Zero Power Physics Reactor (ZPPR) plates and highly enriched uranium (HEU) Jemima plates. The first set of TEX experiments will focus on using the plutonium ZPPR plates with polyethylene moderator and tantalum diluents.

  8. Associação entre tamanho e potencial proliferativo em neurinomas do acústico Size and proliferative index correlation in acoustic neuromas

    Directory of Open Access Journals (Sweden)

    Oswaldo Inácio de Tella

    2006-03-01

    Full Text Available Schwanomas do acústico são os tumores mais freqüentes localizados no ângulo pontocerebelar. Os mecanismos moleculares que levam a sua geração e crescimento ainda não são bem conhecidos. Várias características clínicas, radiológicas e imuno-histoquímicas já foram estudadas e correlacionadas ao crescimento tumoral. Estudamos e correlacionamos aspectos clínicos e imuno-histoquímicos (MIB-1 de 11 schwanomas do acústico operados no Hospital São Paulo/UNIFESP. O tamanho dos tumores correlacionou-se com o índice proliferativo (Ki-67, não havendo correlação com significância estatística entre a idade dos pacientes, duração dos sintomas e índice proliferativo.Acoustic neuromas are the most common tumors in the cerebellopontine angle. The molecular mechanisms involved in generation and growth of these tumors are not completly elucidated. Many radiological, clinic and imunohistochemystry data were correlated to tumor growth. We studied 11 acoustic neuromas surgically treated at Hospital São Paulo/Unifesp and correlated clinical and radiological data with proliferative index (Ki-67. The size of the tumors were positively correlationated with proliferative index. No other correlation had statistic significativity.

  9. Improved DC performance of AlGaN/GaN high electron mobility transistors using hafnium oxide for surface passivation

    International Nuclear Information System (INIS)

    Liu, Chang; Chor, Eng Fong; Tan, Leng Seow

    2007-01-01

    Improved DC performance of AlGaN/GaN high electron mobility transistors (HEMTs) have been demonstrated using reactive-sputtered hafnium oxide (HfO 2 ) thin film as the surface passivation layer. Hall data indicate a significant increase in the product of sheet carrier concentration (n s ) and electron mobility (μ n ) in the HfO 2 -passivated HEMTs, compared to the unpassivated HEMTs. This improvement in electron carrier characteristics gives rise to a 22% higher I Dmax and an 18% higher g mmax in HEMTs with HfO 2 passivation relative to the unpassivated devices. On the other hand, I gleak of the HEMTs decreases by nearly one order of magnitude when HfO 2 passivation is applied. In addition, drain current is measured in the subthreshold regime. Compared to the unpassivated HEMTs, HfO 2 -passivated HEMTs exhibit a much smaller off-state I D , indicating better turn-off characteristics

  10. Protective coatings of hafnium dioxide by atomic layer deposition for microelectromechanical systems applications

    Energy Technology Data Exchange (ETDEWEB)

    Berdova, Maria, E-mail: maria.berdova@aalto.fi [Aalto University, Department of Materials Science and Engineering, 02150, Espoo (Finland); Wiemer, Claudia; Lamperti, Alessio; Tallarida, Grazia; Cianci, Elena [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Lamagna, Luca; Losa, Stefano; Rossini, Silvia; Somaschini, Roberto; Gioveni, Salvatore [STMicroelectronics, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Fanciulli, Marco [Laboratorio MDM, IMM CNR, Via C. Olivetti 2, 20864, Agrate Brianza, MB (Italy); Università degli studi di Milano Bicocca, Dipartimento di Scienza dei Materiali, 20126, Milano (Italy); Franssila, Sami, E-mail: sami.franssila@aalto.fi [Aalto University, Department of Materials Science and Engineering, 02150, Espoo (Finland)

    2016-04-15

    Graphical abstract: - Highlights: • Atomic layer deposition of HfO{sub 2} from (CpMe){sub 2}Hf(OMe)Me or Hf(NMeEt){sub 4} and ozone for potential applications in microelectromechanical systems. • ALD HfO{sub 2} protects aluminum substrates from degradation in moist environment and at the same time retains good reflectance properties of the underlying material. • The resistance of hafnium dioxide to moist environment is independent of chosen precursors. - Abstract: This work presents the investigation of HfO{sub 2} deposited by atomic layer deposition (ALD) from either HfD-CO4 or TEMAHf and ozone for microelectromechanical systems (MEMS) applications, in particular, for environmental protection of aluminum micromirrors. This work shows that HfO{sub 2} films successfully protect aluminum in moist environment and at the same time retain good reflectance properties of underlying material. In our experimental work, the chemical composition, crystal structure, electronic density and roughness of HfO{sub 2} films remained the same after one week of humidity treatment (relative humidity of 85%, 85 °C). The reflectance properties underwent only minor changes. The observed shift in reflectance was only from 80–90% to 76–85% in 400–800 nm spectral range when coated with ALD HfO{sub 2} films grown with Hf(NMeEt){sub 4} and no shift (remained in the range of 68–83%) for films grown from (CpMe){sub 2}Hf(OMe)Me.

  11. Correlación entre dimensiones de personalidad de marca y la marca emocional Correlación entre dimensiones de personalidad de marca y la marca emocional

    Directory of Open Access Journals (Sweden)

    José Luis Pirela

    2007-06-01

    Full Text Available Los resultados de la investigación permiten explicar la relación entre los conceptosteóricos de Personalidad de Marca y Marca Emocional. Se han utilizado lasCadenas de Farmacias y los Centros Comerciales como productos de referencia.Se adoptó un muestreo no probabilístico accidental, para totalizar 554 muestrasa través de la aplicación de un cuestionario vía entrevistas personales y correoelectrónico. Para el procesamiento de los datos se aplicó un análisis de correlaciónde rangos de Spearman entre los rasgos de las dimensiones de personalidad y lasreferencias de marca emocional. El 98,5 % de los pares de correlación estudiadospresentaron valores superiores a α = 0,48, que no evidenció una asociación signifi -cativa entre las variables de estudio; esto lleva a concluir que en este caso no existeuna clara asociación entre marca emocional y personalidad de marca.The results from this study allow us to explain the relation between the two theoretical concepts  of brand personality and emotional branding. Pharmacy franchises and shopping centers were used as product references. A non-accidental probablistic sampling was used, for a total of 554 samples gathered by means of a questionaire administered via in-person  interviews or by Internet. The data was processed by applying Spearman’s correlation of ranges analysis to compare the features of the dimensions of personality and the emotional branding references. 98.5% of the correlation pairs studied showed values above a = 0.48, which represented no signifi cant association between the two variables under consideration. This leads us to the conclusion that in this case no clear relation exists between emotional branding and brand personality

  12. Correlação entre os testes da caminhada, marcha estacionária e TUG em hipertensas idosas Correlation between the walk, 2-minute step and TUG tests among hypertensive older women

    Directory of Open Access Journals (Sweden)

    R Pedrosa

    2009-06-01

    Full Text Available CONTEXTUALIZAÇÃO: O aumento de doenças crônicas em idosos, principalmente da Hipertensão Arterial Sistêmica, doença intimamente relacionada ao declínio da capacidade funcional, determina a necessidade do estudo de métodos de avaliação da realização das atividades, possibilitando detecção de níveis de capacidade funcional, prescrição de exercícios e acompanhamento das funções cardiovascular e motora. O teste da caminhada de 6 minutos (TC6', o teste da Marcha Estacionária de 2 minutos (TME2' e o teste Timed Up and Go (TUG são indicados para esta avaliação. Estudos em idosos saudáveis mostram a associação entre esses testes, facilitando a avaliação da capacidade funcional. Porém, em hipertensos, não existem estudos que avaliem a relação entre TC6', TME2'e TUG, justificando a realização desta pesquisa. OBJETIVOS: Verificar se existe associação entre endurance aeróbia e a mobilidade funcional em idosas hipertensas. MÉTODOS: Estudo observacional, analítico e transversal, com 32 hipertensas idosas, avaliadas por meio do TC6', TME2' e TUG. RESULTADOS:Houve correlação positiva moderada entre TC6' e TME2', r=0,36 (p=0,04 e correlação negativa moderada entre TC6'e TUG, r=-0,59 (p=0,000 e entre TME2' e TUG, r=-0,66 (p=0,000. CONCLUSÕES: Para hipertensas idosas, o TC6' pode ser substituído pelo TME2', assim como em idosos saudáveis. Quanto à correlação entre os TC6', TME2' e TUG, pode-se concluir que existe uma íntima relação entre resistência cardiovascular e mobilidade funcional; havendo menor resistência cardiovascular, há mobilidade funcional precária e vice-versa.BACKGROUND: The increase in chronic diseases among older adults, especially systemic arterial hypertension, a disease that is closely related to declining functional capacity, has created the need to study methods for activity evaluation in order to detect functional capacity levels, prescribe exercises and monitor motor and

  13. Correlação entre gestão da tecnologia e gestão ambiental nas empresas Correlation between technology management and environmental management in the companies

    Directory of Open Access Journals (Sweden)

    José Carlos Teixeira da Silva

    2005-08-01

    Full Text Available Este trabalho analisa a correlação entre a gestão da tecnologia de produtos e processos e a gestão ambiental em empresas de manufatura. Partindo de um modelo conceitual simplificado e desdobramentos das dimensões gestão da tecnologia e gestão ambiental, foi possível analisar em pesquisa de campo vários conceitos disponíveis na literatura para esses dois campos, envolvendo 78 empresas do setor de manufaturados, através de "projeto de pesquisa survey" e "projeto de pesquisa qualitativa". Visando avaliar a capabilidade tecnológica das organizações, foram usados os conceitos de microtecnologia e macrotecnologia relatados em Silva (2003. Concluiu-se que, dentro do campo pesquisado de empresas, existe correlação positiva entre os níveis de capabilidade tecnológica e os níveis de capabilidade ambiental.This work analyzes the correlation between the technology management of products and processes and the environmental management, in manufacture companies. Leaving from a simplified conceptual model, and doing deployment of the dimensions technology management and environmental management, it was possible to analyze several concepts available in the literature for these fields, involving 78 manufacture companies, through "survey research project" and "qualitative research project", regarding also the technology capability of the organization through the new concepts of microtecnologia and macrotecnologia related in Silva (2003. It concluded that, inside the field searched of companies, there is a positive correlation between the levels of technology capability and environmental capability.

  14. Efficient UV-emitting X-ray phosphors: octahedral Zr(PO4)6 luminescence centers in potassium hafnium-zirconium phosphates K2Hf1-xZrx(PO4)2 and KHf2(1-x)Zr2x(PO4)3

    International Nuclear Information System (INIS)

    Torardi, C.C.; Miao, C.R.; Li, J.

    2003-01-01

    Potassium hafnium-zirconium phosphates, K 2 Hf 1-x Zr x (PO 4 ) 2 and KHf 2(1-x) Zr 2x (PO 4 ) 3 , are broad-band UV-emitting phosphors. At room temperature, they have emission peak maxima at approximately 322 and 305 nm, respectively, under 30 kV peak molybdenum X-ray excitation. Both phosphors demonstrate luminescence efficiencies that make them up to ∼60% as bright as commercially available CaWO 4 Hi-Plus. The solid-state and flux synthesis conditions, and X-ray excited UV luminescence of these two phosphors are discussed. Even though the two compounds have different atomic structures, they contain zirconium in the same active luminescence environment as that found in highly efficient UV-emitting BaHf 1-x Zr x (PO 4 ) 2 . All the three materials have hafnium and zirconium in octahedral coordination via oxygen-atom corner sharing with six separate PO 4 tetrahedra. This octahedral Zr(PO 4 ) 6 moiety appears to be an important structural element for efficient X-ray excited luminescence, as are the edge-sharing octahedral TaO 6 chains for tantalate emission

  15. Capacidade combinatória, divergência genética entre linhagens de milho e correlação com heterose Combining ability, genetic divergence among maize lines and correlation with heterosis

    Directory of Open Access Journals (Sweden)

    Maria Elisa Ayres Guidetti Zagatto Paterniani

    2008-01-01

    Full Text Available Objetivou-se avaliar o desempenho de híbridos simples de milho (Zea mays L., obtidos de cruzamentos dialélicos entre linhagens divergentes, estimar a capacidade de combinação das linhagens e verificar se a divergência genética entre as linhagens, obtida por marcadores moleculares, é correlacionada com a heterose dos híbridos simples no campo. Trinta e seis híbridos resultantes de um dialelo parcial foram avaliados em Campinas e em Mococa e as 12 linhagens parentais somente em Campinas, a fim de se calcular a heterose dos híbridos. O delineamento experimental empregado foi o de blocos ao acaso, com três repetições e 2 testemunhas comerciais. Avaliaram-se os caracteres: altura da planta (AP, altura da espiga (AE e massa de grãos (MG. Análises de variância foram efetuadas, sendo as médias comparadas entre si pelo teste de Tukey a 5%. A capacidade de combinação das linhagens foi obtida de acordo com o método de Geraldi e Miranda Filho. Estimaram-se as correlações entre heterose, produtividade e capacidade específica de combinação com divergência genética obtida por AFLP e SSR. Destacou-se o híbrido PM624 x IP398, e as linhagens VER266 e L105 revelaram efeitos positivos da capacidade de combinação para produtividade. As estimativas de heterose variaram de -559 a 6.320 kg ha-1. Não houve correlação entre heterose, capacidade específica de combinação e produtividade dos híbridos com a distância genética por AFLP e SSR, indicando que não é possível fazer inferências sobre o comportamento dos híbridos de milho a partir da divergência genética entre as linhagens parentais.The objectives of this research were to evaluate single cross hybrids of maize (Zea mays L. obtained from partial diallel crosses among contrasting inbred lines, to estimate the combining ability of the lines and to verify whether the genetic diversity among those lines assessed by moleculars markers is correlated with single cross hybrid

  16. Correlations between yield and fruit quality characteristics of fresh market tomatoes Correlações entre caracteres de produção e qualidade de frutos de tomate de mesa

    Directory of Open Access Journals (Sweden)

    Lívia M de Souza

    2012-12-01

    Full Text Available Genotypic, phenotypic and environmental correlations were estimated for all possible pairs among eleven characters of tomatoes. Fifteen treatments including five parents and ten hybrids of Instituto Agronômico (IAC tomato breeding program were evaluated using a randomized complete block experimental design, with tree replications in Itatiba, São Paulo state, Brazil, during 2005/2006. The following traits were evaluated: fruit yield per plant (FP, fruit number per plant (FN, average fruit weight (FW, cluster number per plant (CN, fruit number per cluster (FC, number of locules per fruit (NL, fruit length (FL, fruit width (WI, fruit wall thickness (FT, total soluble solids (SS, and total titratable acidity (TA. The genotypic (rG, phenotypic (rF and environmental correlations (rA for two pairs of plant traits were estimated using the Genes© program. High similarity was found among the estimates of genotypic and phenotypic correlations. Positive and high phenotypic and genotypic correlations were observed between FP and the traits FN, FW and FT, and these associations contributed for yield increasing. FW and FT contributed to yield increase and should be considered together as primary yield components in tomato. Positive values of the genotypic and phenotypic correlations revealed that FP influenced FN with high direct effect and significant positive correlation. These traits may be included as the main selection criteria for tomato yield improvement.Correlações fenotípica, genotípica e ambiental foram estimadas entre todos os possíveis pares de onze caracteres de tomate de mesa. Quinze tratamentos, incluindo cinco parentais e dez híbridos do programa de melhoramento de tomate do Instituto Agronômico (IAC foram testados no delineamento em blocos casualizados completos, em Itatiba-SP, em 2005/2006. Os seguintes caracteres foram avaliados: produção (FP, número (FN e peso médio do fruto (FW, número de pencas por planta (CN, número de

  17. Correlação entre tempo, erro, velocidade e compreensão de leitura em escolares com distúrbio de aprendizagem Correlation between time, error, speed and reading comprehension in students with learning disorders

    Directory of Open Access Journals (Sweden)

    Cláudia da Silva

    2011-12-01

    Full Text Available OBJETIVO: Correlacionar as variáveis: erros, tempo, velocidade e compreensão de leitura de escolares com distúrbios de aprendizagem e escolares sem dificuldade de aprendizagem. MÉTODOS: Participaram deste estudo 40 escolares de 8 a 12 anos de idade, de ambos os gêneros, de 2ª a 4ª série do Ensino Fundamental Municipal, divididos em GI: composto por 20 escolares sem dificuldade de aprendizagem e GII: composto por 20 escolares com distúrbio de aprendizagem. Foram utilizados textos selecionados a partir da indicação de professores da 2ª à 4ª série da Rede Municipal de Ensino, para a realização de leitura oral. A compreensão foi realizada por meio de quatro perguntas apresentadas após a leitura do texto, às quais os escolares deveriam responder oralmente. RESULTADOS: Houve diferença entre GI e GII no número de erros, velocidade e compreensão de leitura e tempo total de leitura. A correlação entre tempo total de leitura e erros cometidos durante a leitura foi positiva, e entre as variáveis tempo total de leitura e velocidade de leitura foi negativa. Para o grupo GII, houve diferença com correlação negativa entre as variáveis tempo total de leitura e velocidade de leitura. CONCLUSÃO: Para os escolares com distúrbio de aprendizagem, o desempenho nas variáveis que foram correlacionadas encontra-se alterado interferindo no desenvolvimento em leitura e, consequentemente, na compreensão do texto lido.PURPOSE: To correlate the variables error, time, speed and reading comprehension of students with learning disorders and students without learning disorders. METHODS: The participants of this study were 40 students, aged from 8 to 12 years old, of both genders, from 2nd to 4th grades of municipal elementary education, divided into GI: comprising 20 students without learning disorders, and GII: comprising 20 students with learning disorders. As procedure we used a selection of texts indicated by teachers of 2nd to 4th grades of

  18. Recovery of metal chlorides from their complexes by molten salt displacement

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1989-01-01

    This patent describes a process for recovering zirconium or hafnium chloride from a complex of zirconium or hafnium tetrachloride and phosphorus oxychloride. The process comprising: introducing liquid complex of zirconium or hafnium tetrachloride and phosphorus oxychloride into an upper portion of a feed column containing zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor. The liquid complex absorbing zirconium or hafnium tetrachloride vapor and producing a bottoms liquid and also producing a phosphorus oxychloride vapor stripped of zirconium or hafnium tetrachloride; introducing the bottoms liquid into a molten salt containing displacement reactor, the reactor containing molten salt comprising at least 30 mole percent lithium chloride and at least 30 mole percent of at least one other alkali metal chloride, the reactor being heated to 30-450 0 C to displace phosphorus oxychloride from the complex and product zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor and zirconium or hafnium tetrachloride-containing molten salt; introducing the zirconium or hafnium tetrachloride vapor and the phosphorus oxychloride vapor into the feed column below the point of introduction of the liquid stream; introducing the zirconium or hafnium tetrachloride containing-molten salt into a recovery vessel where zirconium or hafnium tetrachloride is removed from the molten salt to produce zirconium or hafnium tetrachloride product and zirconium or hafnium chloride-depleted molten salt; and recycling the zirconium or hafnium tetachloride-depleted molten salt to the displacement reactor

  19. Relações entre /s/ e /z/ e entre /e/ e /e/ não vozeado ou áfono Relations between /s/ and /z/ and between /e/ and voiceless /e/

    Directory of Open Access Journals (Sweden)

    Carla Aparecida Cielo

    2013-01-01

    Full Text Available OBJETIVO: correlacionar os tempos máximos de fonação (TMF e as relações entre os fricativos /s/ e /z/ (s/z e entre /e/ não vozeado e a vogal /e/ (ė/e de mulheres sem afecções laríngeas. MÉTODO: participaram 60 mulheres com média de 21,56 anos de idade. Coletaram-se os TMF/ė/, /e/, /s/ e /z/ e calcularam-se a relação s/z e a relação ė/e, com padrão de normalidade para as relações de 0,8 a 1,2; para os TMF/s/ e /z/, entre 15,57 e 34,17s; para o TMF/ė/, entre 16 a 18s; e para o TMF/e/, entre 14,04 e 26,96s. Testes de Lilliefords, Spearmann, Binomial e Mann-Whitney com nível de significância de 5%. RESULTADOS: correlação positiva entre TMF/s/ e TMF/ė/, TMF/z/ e TMF/e/, TMF/s/ e TMF/z/, e TMF/ė/ e TMF/e/. Não houve correlação entre as relações s/z e ė/e, nem diferenças entre a relação ė/e, enquanto a relação s/z foi significantemente normal. TMF/ė/ e TMF/e/ significantemente diminuídos; TMF/s/ e TMF/z/ significantemente normais. TMF/ė/ significantemente menor do que TMF/s/; TMF/e/ significantemente menor do que TMF/z/. CONCLUSÃO: os fonemas /s/ e /z/ isolados e sua relação ficaram dentro da normalidade e as relações s/z e ė/e não apresentaram correlação. Os TMF/ė/ e TMF/e/ mostraram-se diminuídos em relação à normalidade. O TMF/ė/ foi menor do que TMF/s/ e o TMF/e/ foi menor do que TMF/z/, possivelmente devido ao modo articulatório dos fricativos ter aumentado o tempo de emissão, independentemente do controle do nível glótico e respiratório.PURPOSE: correlate the maximum phonation time (MPT and the relations between the fricative /s/ and /z/ (s/z and between the vowels /ė/ and /e/ (ė/e of women without laryngeal disorders. METHOD: participants were 60 women with a mean of 21.56 years old. Were collected MPT/ė/, /e/, /s/ and /z/ and calculated the relations ė/e and s/z, with normal pattern for the relationship from 0.8 to 1.2; for MPT/s/ and MPT/z/, between 15.57 and 34.17s; for the

  20. Growth of HfO{sub x} thin films by reactive molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany)

    2008-07-01

    Thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. The conditions for the growth of single oriented hafnium oxide thin films have been established. Hafnium oxide thin films were characterized by X-ray diffraction and optical absorption measurements. It was found that hafnium oxide thin films grown on r-cut sapphire were (00l) oriented whereas, on c-cut sapphire, hafnium oxide films showed different orientations depending on the growth temperature and oxidation conditions. The hafnium oxide films grown at higher temperature and under strong oxidation conditions yielded (001) oriented films on c-cut sapphire whereas slightly weaker oxidation condition leads to (111) oriented hafnium oxide films. The bandgap deducted from optical absorption measurement carried out on hafnium oxide films grown under optimized conditions agreed well with the values reported in literature. A range of oxygen deficient thin films of hafnium oxide were also grown on single crystal sapphire substrates in order to investigate the effect of oxygen vacancies on dielectric properties of hafnium oxide. The oxygen deficient thin films of hafnium oxide show a decrease in bandgap with increase in oxygen deficiency.

  1. Relação entre diferentes caracteres de plantas jovens de seringueira Correlations and regressions studies among juvenile rubber tree characters

    Directory of Open Access Journals (Sweden)

    César Lavorenti

    1990-01-01

    Full Text Available O presente trabalho foi realizado com o objetivo de determinar a existência e as magnitudes de correlações e regressões lineares simples em plântulas jovens de seringueira (Hevea spp., para melhor condução de seleção nos futuros trabalhos de melhoramento. Foram utilizadas médias de produção de borracha seca por plântulas por corte, através do teste Hamaker-Morris-Mann (P; circunferência do caule (CC; espessura de casca (EC; número de anéis (NA; diâmetro dos vasos (DV; densidade dos vasos laticíleros (D e distância média entre anéis de vasos consecutivos (DMEAVC em um viveiro de cruzamento com três anos e meio de idade. Os resultados mostraram, entre outros fatores, que as correlações lineares simples de P com CC, EC, NA, D, DV e DMEAVC foram, respectivamente, r =t 0,61, 0,34, 0,28, 0,29, 0,43 e -0,13. As correlações de CC com EC, NA, D, DV e DMEAVC foram: 0,65, 0,22, 0,37, 0,33 e 0,096 respectivamente. Estudos de regressão linear simples de P com CC, EC, NA, DV, D e DMEAVC sugerem que CC foi o caráter independente mais significativo, contribuindo com 36% da variação em P. Em relação ao vigor, a regressão de CC com os respectivos caracteres sugere que EC foi o único caráter que contribuiu significativamente para a variação de CC com 42%. As altas correlações observadas da produção com circunferência do caule e com espessura de casca evidenciam a possibilidade de obter genótipos jovens de boa capacidade produtiva e grande vigor, através de seleção precoce dessas variáveis.This study was undertaken aiming to determine the existence of linear correlations, based on simple regression studies for a better improvement of young rubber tree (Hevea spp. breeding and selection. The characters studied were: yield of dry rubber per tapping by Hamaker-Morris-Mann test tapping (P, mean gurth (CC, bark thickness (EC, number of latex vessel rings (NA, diameter of latex vesseis (DV, density of latex vesseis per 5mm

  2. Correlação entre a contagem dos pontos dolorosos na fibromialgia com a intensidade dos sintomas e seu impacto na qualidade de vida Correlation between the number of tender points in fibromyalgia, the intensity of symptoms and its impact on quality of life

    Directory of Open Access Journals (Sweden)

    José Eduardo Martinez

    2009-02-01

    Full Text Available OBJETIVO: Estabelecer se há correlação entre o número de pontos dolorosos e a intensidade da percepção de aspectos centrais da síndrome (dor, fadiga, ansiedade, depressão e do seu impacto na capacidade funcional. MATERIAL E MÉTODOS: Avaliaram-se quarenta e um prontuários de pacientes que preenchem os Critérios de Classificação para Fibromialgia do Colégio Americano de Reumatologia, considerando as seguintes variáveis: percepção da intensidade de dor, fadiga, qualidade de vida global, depressão, ansiedade e contagem de pontos dolorosos. A avaliação da capacidade funcional foi realizada através do Questionário de Avaliação de Saúde simplificado (Health Assessment Questionnaire-HAQ. RESULTADOS: Observou-se correlação entre a contagem de pontos dolorosos e a intensidade da dor e a capacidade funcional. Não houve correlação com as notas atribuídas à fadiga (p = 0,358, ansiedade (p = 0,58, depressão (p = 0,50 e qualidade de vida (p = 0,538. A correlação entre o número de pontos dolorosos e a intensidade da dor foi mais forte que com o HAQ. CONCLUSÃO: Há correlação entre contagem dos pontos dolorosos e intensidade da dor e capacidade funcional. A correlação entre os pontos dolorosos e a intensidade da dor é mais importante do que com a capacidade funcional medida pelo HAQ. Não há correlação com as demais variáveis estudadas.OBJECTIVE: to study the correlation between the number of tender points and the intensity of the perception of key aspects of the fibromyalgia syndrome (pain, fatigue, anxiety, depression, and its impact in functional capacity. MATERIAL AND METHODS: forty-one records of patients who meet the Criteria for Classification of Fibromyalgia of the American College of Rheumatology were reviewed, focusing on the following variables: perception of the intensity of pain, fatigue, quality of sleep, depression, anxiety and the tender point count. The assessment of functional capacity was done by

  3. Evaluation and Enhancement of the Oxygen Reduction Reaction Activity on Hafnium Oxide Nanoparticles Assisted by L(+)-lysine

    International Nuclear Information System (INIS)

    Chisaka, Mitsuharu; Itagaki, Noriaki

    2016-01-01

    Evaluation of the oxygen reduction reaction (ORR) on oxide compounds is difficult owing to the insulating nature of oxides. In this study, various amounts of L(+)-lysine were added to the precursor dispersion for the hydrothermal synthesis of hafnium oxide nanoparticles on reduced graphene oxide sheets (HfO_x–rGO) to coat the HfO_x catalysts with layers of carbon, thereby increasing the conductivity and number of active sites. When the mass ratio of L(+)-lysine to GO, R, was above 26, carbon layers were formed and the amount monotonically increased with increasing R, as noted by cyclic voltammogrametry. X-ray photoelectron spectroscopy and rotating disk electrode analyses revealed that pyrolysis produced ORR-active oxygen defects, whose formation was proposed to involve carbothermal reduction. When 53 ≤ R ≤ 210, HfO_x–rGO contained a similar amount of oxygen defects and ORR activity, as represented by an onset potential of 0.9 V versus the reversible hydrogen electrode in 0.1 mol dm"−"3 H_2SO_4. However, the number of active sites depended on R due to the amount of L(+)-lysine-derived carbon layers that increased both the number of active sites and resistivity towards oxygen diffusion.

  4. Mechanistic Studies of Hafnium-Pyridyl Amido-Catalyzed 1-Octene Polymerization and Chain Transfer Using Quench-Labeling Methods.

    Science.gov (United States)

    Cueny, Eric S; Johnson, Heather C; Anding, Bernie J; Landis, Clark R

    2017-08-30

    Chromophore quench-labeling applied to 1-octene polymerization as catalyzed by hafnium-pyridyl amido precursors enables quantification of the amount of active catalyst and observation of the molecular weight distribution (MWD) of Hf-bound polymers via UV-GPC analysis. Comparison of the UV-detected MWD with the MWD of the "bulk" (all polymers, from RI-GPC analysis) provides important mechanistic information. The time evolution of the dual-detection GPC data, concentration of active catalyst, and monomer consumption suggests optimal activation conditions for the Hf pre-catalyst in the presence of the activator [Ph 3 C][B(C 6 F 5 ) 4 ]. The chromophore quench-labeling agents do not react with the chain-transfer agent ZnEt 2 under the reaction conditions. Thus, Hf-bound polymeryls are selectively labeled in the presence of zinc-polymeryls. Quench-labeling studies in the presence of ZnEt 2 reveal that ZnEt 2 does not influence the rate of propagation at the Hf center, and chain transfer of Hf-bound polymers to ZnEt 2 is fast and quasi-irreversible. The quench-label techniques represent a means to study commercial polymerization catalysts that operate with high efficiency at low catalyst concentrations without the need for specialized equipment.

  5. Reactive evaporation of low-defect density hafnia

    International Nuclear Information System (INIS)

    Chow, R.; Falabella, S.; Loomis, G.E.; Rainer, F.; Stolz, C.J.; Kozlowski, M.R.

    1993-01-01

    Motivation for this work includes observations at Lawrence Livermore National Laboratory of a correlation between laser damage thresholds and both the absorption and the nodular-defect density of coatings. Activated oxygen is used to increase the metal-oxidation kinetics at the coated surface during electron-beam deposition. A series of hafnia layers are made with various conditions: two μ-wave configuations, two sources (hafnium and hafnia), and two reactive oxygen pressures. Laser damage thresholds (1064-nm, 10-ns pulses), absorption (at 511 nm), and nodular-defect densities from these coatings are reported. The damage thresholds are observed to increase as the absorption of the coatings decreases. However, no significant increase in damage thresholds are observed with the coatings made from a low nodular-defect density source material (hafnium). Hafnia coatings can be made from hafnium sources that have lower nodular-defect densities, lower absorption, and damage thresholds that are comparable with coatings made from a conventional hafnia source

  6. Correlation between visual and radiographic examinations of non-cavitated occlusal caries lesions: an in vivo study Correlação entre os exames visual e radiográfico de lesões de cárie oclusal não cavitadas: estudo in vivo

    Directory of Open Access Journals (Sweden)

    Victor Ferrás Wolwacz

    2004-06-01

    Full Text Available The aim of this study was to conduct an in vivo investigation of the correlation between the visual and radiographic scoring systems by Ekstrand et al.7 (1997 for the diagnosis of occlusal caries lesions. The study sample comprised 147 occlusal sites from 23 patients. Two trained and experienced examiners performed the clinical visual examinations. A third examiner, which was also trained, experienced and blind to the results of the visual clinical examination, performed the analysis of the bitewing radiographs. The correlation between visual and radiographic scores was assessed by Goodman & Kruskal's gamma correlation coefficient. Results showed a strong correlation between the scores for occlusal caries found in the visual and radiographic diagnosis systems used in this study.O presente estudo verificou in vivo a correlação existente entre os sistemas de escore visual e radiográfico de Ekstrand et al.7 (1997 para diagnóstico de lesões de cárie oclusal. A amostra do estudo foi constituída de 147 sítios oclusais obtidos a partir de 23 pacientes. Os exames clínicos visuais foram realizados por dois examinadores treinados e calibrados. A análise das radiografias interproximais foi realizada por um terceiro examinador também treinado e calibrado, que desconhecia os resultados do exame clínico visual. A correlação entre os escores visual e radiográfico foi avaliada por meio do coeficiente de correlação gamma de Goodman & Kruskal. Os resultados revelaram uma forte correlação existente entre os escores dos sistemas de diagnóstico visual e radiográfico de cárie oclusal adotados no presente estudo.

  7. Characteristics of laser produced plasmas of hafnium and tantalum in the 1-7 nm region

    Science.gov (United States)

    Li, Bowen; Otsuka, Takamitsu; Sokell, Emma; Dunne, Padraig; O'Sullivan, Gerry; Hara, Hiroyuki; Arai, Goki; Tamura, Toshiki; Ono, Yuichi; Dinh, Thanh-Hung; Higashiguchi, Takeshi

    2017-11-01

    Soft X-ray (SXR) spectra from hafnium and tantalum laser produced plasmas were recorded in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 170 ps and 10 ns, respectively, operating at a range of power densities. The maximum focused peak power density was 2. 3 × 1014 W cm-2 for 170 ps pulses and 1. 8 × 1012 W cm-2 for 10 ns pulses, respectively. Two intense quasicontinuous intensity bands resulting from n = 4 - n = 4 and n = 4 - n = 5 unresolved transition arrays (UTAs) dominate both sets of experimental spectra. Comparison with calculations performed with the Cowan suite of atomic structure codes as well as consideration of previous experimental and theoretical results aided identification of the most prominent features in the spectra. For the 10 ns spectrum, the highest ion stage that could be identified from the n = 4 - n = 5 arrays were lower than silver-like Hf25+ and Ta26+ (which has a 4 d 104 f ground configuration) indicating that the plasma temperature attained was too low to produce ions with an outermost 4 d subshell, while for the 170 ps plasmas the presence of significantly higher stages was deduced and lines due to 4 d-5 p transitions were clearly evident. Furthermore, we show an enhancement of emission from tantalum using dual laser irradiation, and the effect of pre-pulse durations and delay times between two pulses are demonstrated.

  8. Effets Josephson generalises entre antiferroaimants et entre supraconducteurs antiferromagnetiques

    Science.gov (United States)

    Chasse, Dominique

    L'effet Josephson est generalement presente comme le resultat de l'effet tunnel coherent de paires de Cooper a travers une jonction tunnel entre deux supraconducteurs, mais il est possible de l'expliquer dans un contexte plus general. Par exemple, Esposito & al. ont recemment demontre que l'effet Josephson DC peut etre decrit a l'aide du boson pseudo-Goldstone de deux systemes couples brisant chacun la symetrie abelienne U(1). Puisque cette description se generalise de facon naturelle a des brisures de symetries continues non-abeliennes, l'equivalent de l'effet Josephson devrait donc exister pour des types d'ordre a longue portee differents de la supraconductivite. Le cas de deux ferroaimants itinerants (brisure de symetrie 0(3)) couples a travers une jonction tunnel a deja ete traite dans la litterature Afin de mettre en evidence la generalite du phenomene et dans le but de faire des predictions a partir d'un modele realiste, nous etudions le cas d'une jonction tunnel entre deux antiferroaimants itinerants. En adoptant une approche Similaire a celle d'Ambegaokar & Baratoff pour une jonction Josephson, nous trouvons un courant d'aimantation alternee a travers la jonction qui est proportionnel a sG x sD ou fG et sD sont les vecteurs de Neel de part et d'autre de la jonction. La fonction sinus caracteristique du courant Josephson standard est donc remplacee.ici par un produit vectoriel. Nous montrons que, d'un point de vue microscopique, ce phenomene resulte de l'effet tunnel coherent de paires particule-trou de spin 1 et de vecteur d'onde net egal au vecteur d'onde antiferromagnetique Q. Nous trouvons egalement la dependance en temperature de l'analogue du courant critique. En presence d'un champ magnetique externe, nous obtenons l'analogue de l'effet Josephson AC et la description complete que nous en donnons s'applique aussi au cas d'une jonction tunnel entre ferroaimants (dans ce dernier cas, les traitements anterieurs de cet effet AC s'averent incomplets). Nous

  9. Correlação entre características quantitativas e qualitativas de frutos de pessegueiros na geração F2 cultivados em região subtropical Correlation between quantitative and qualitative characteristics of fruits of peach trees grown in subtropical conditions

    Directory of Open Access Journals (Sweden)

    Danielle Fabíola Pereira Silva

    2013-02-01

    Full Text Available O objetivo deste trabalho foi avaliar as relações entre características quantitativas e qualitativas de frutos de pessegueiro, cultivados em região subtropical. Para isso foram utilizados frutos totalmente maduros, obtidos de cinco populações, em geração F2, cultivadas em condições de clima subtropical. Foram avaliados: coloração da epiderme (coordenadas b* e h°, diâmetro médio do fruto, comprimento do fruto, firmeza instrumental da polpa, teor de sólidos solúveis, acidez titulável, teor de ácido ascórbico, percentagem de vermelho na epiderme, coloração da polpa, aderência do caroço, consistência manual da polpa e época de colheita. Os dados foram utilizados para obtenção de coeficientes parciais de correlação entre todas as variáveis. Observou-se variação entre os valores obtidos para cada característica. Há correlações parciais significativas a 1% de probabilidade, de intensidades médias e fracas, entre as características estudadas de frutos de pessegueiro. As maiores correlações foram obtidas entre comprimento e diâmetro de frutos (0,690** e entre os descritores b e h, obtidos por meio de colorímetro (0,516**. Frutos mais tardios apresentam, geralmente, maior firmeza de polpa, menores teores de vitamina C e menos pigmentação amarela na epiderme. Pêssegos de polpa amarela são mais firmes e apresentam maior acidez no suco.The objective this study was to evaluate the relationship between quantitative and qualitative characteristics of peach grown in subtropical regions. Fully ripe fruits obtained from five F2 populations grown in a subtropical climate were evaluated for: skin color (coordinates b* and h°, average fruit diameter, fruit length, pulp instrumental firmness, soluble solids, titratable acidity, ascorbic acid, percentage of red skin, flesh color , flesh adherence to pit, pulp consistency and harvest time. These data were used to obtain partial correlation coefficients of all variables

  10. Sobre a correlação entre a bioética e a psicologia médica About correlation between bioethics and medical psychology

    Directory of Open Access Journals (Sweden)

    José Alvaro Marques Marcolino

    2008-08-01

    Full Text Available Os autores realizam um estudo a respeito de uma correlação entre a bioética e a psicologia médica. Dividem o trabalho em duas partes. A primeira discute os conceitos filosóficos sobre a distinção entre moral e ética, trata da ética ligada à medicina e dedica-se à bioética, procurando definir o que se compreende por essa disciplina, descrevendo seus três princípios básicos: a autonomia, a beneficência, não-maleficência e a justiça. Portanto, traça nesta parte do trabalho, uma trajetória que partiu da ética em sua vertente filosófica até chegar à ética em sua aplicação à medicina. A segunda parte é dedicada a definição do campo da psicologia médica, estudando aspectos da relação emocional do indivíduo doente com a sua doença, da relação do médico com a medicina e enfoca o relacionamento do médico com seu paciente. Discutem algumas situações clínicas em que se observa essa correlação. No final, buscam elaborar algumas conclusões.The authors make a study about the correlation between bioethics and medical psychology. They divide the study in two parts. The first part they discuss the philosophical concepts about the distinction between morals and ethics, they deal with ethics applied to medicine and they are trying to define what is meant by subject and describe its three basic principles: autonomy, beneficence, non maleficence and justice. Consequently in this part they trace route that started from ethics in its philosophical origins and moved on to ethics in its application to medicine. The second part is dedicated to the definition of the field of study of medical psychology, they study some aspects of the emotional relation of the patient with his illness, the relation of the doctors of his medicine and the relacionship between doctor and his patient. They discusse some clinical issues where they observe this correlation. At last, they try to draw some conclusions.

  11. X-ray tube target

    International Nuclear Information System (INIS)

    Weber, R.G.

    1980-01-01

    A target with an improved heat emissive surface for use in a rotating anode type x-ray tube is described. The target consists of a body having a first surface portion made of x-ray emissive material and a second surface portion made of a heat emissive material comprising at least one of hafnium boride, hafnium oxide, hafnium nitride, hafnium silicide, and hafnium aluminide. (U.K.)

  12. Correlación ecológica entre consumo de bebidas alcohólicas y mortalidad por cirrosis hepática en México Ecological correlation between alcohol use and cirrhosis mortality in Mexico

    Directory of Open Access Journals (Sweden)

    JOSÉ NARRO-ROBLES

    1997-05-01

    Full Text Available Objetivo. Determinar la correlación entre consumo de bebidas alcohólicas y mortalidad por cirrosis hepática. Material y métodos. Se efectuó un análisis de correlación ecológica entre el conjunto de variables que integran el patrón de consumo de bebidas alcohólicas investigadas en la Encuesta Nacional de Adicciones en 1993 y la mortalidad por cirrosis hepática, en el periodo 1971-1993 en las ocho regiones en que fue dividido el país. Para determinar el nivel de correlación se utilizaron los coeficientes de correlación de Pearson y de Spearman. Resultados. Solamente se encontró correlación significativa con la prevalencia de bebedores de bebidas destiladas, pulque y cerveza; con esta última la correlación fue negativa. Conclusiones. Aunque se considera que el consumo de pulque es limitado, llama la atención su asociación con la mortalidad por cirrosis hepática. La correlación negativa con la cerveza se interpreta en el sentido de que el consumo de esta bebida no es buen indicador de alcoholismo. Los resultados, aunque sin ser definitivos, muestran la necesidad de efectuar una acción de intervención efectiva en las entidades federativas con exceso de consumo de bebidas destiladas y pulque.Objective. To determine the correlation between alcohol consumption and mortality from liver cirrhosis in Mexico. Material and methods. Analysis of the ecological correlation between the patterns of alcohol consumption determined by the National Addiction Survey in 1993 and mortality by liver cirrhosis, in the period between 1971-1993, in the eight regions in which the country was divided. To determine level of correlation, the Pearson and Spearman coefficients were calculated. Results. Significant correlations were only found with the prevalence of spirits and pulque drinkers; with beer drinkers the correlation was negative. Conclusions. The correlation with pulque is interesting, since pulque consumption is considered to be low scale in

  13. Materials properties of hafnium and zirconium silicates: Metal interdiffusion and dopant penetration studies

    Science.gov (United States)

    Quevedo Lopez, Manuel Angel

    Hafnium and Zirconium based gate dielectrics are considered potential candidates to replace SiO2 or SiON as the gate dielectric in CMOS processing. Furthermore, the addition of nitrogen into this pseudo-binary alloy has been shown to improve their thermal stability, electrical properties, and reduce dopant penetration. Because CMOS processing requires high temperature anneals (up to 1050°C), it is important to understand the diffusion properties of any metal associated with the gate dielectric in silicon at these temperatures. In addition, dopant penetration from the doped polysilicon gate into the Si channel at these temperatures must also be studied. Impurity outdiffusion (Hf, Zr) from the dielectric, or dopant (B, As, P) penetration through the dielectric into the channel region would likely result in deleterious effects upon the carrier mobility. In this dissertation extensive thermal stability studies of alternate gate dielectric candidates ZrSixOy and HfSixO y are presented. Dopant penetration studies from doped-polysilicon through HfSixOy and HfSixOyNz are also presented. Rutherford Backscattering Spectroscopy (RBS), Heavy Ion RBS (HI-RBS), X-ray Photoelectron Spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HR-TEM), and Time of Flight and Dynamic Secondary Ion Mass Spectroscopy (ToF-SIMS, D-SIMS) methods were used to characterize these materials. The dopant diffusivity is calculated by modeling of the dopant profiles in the Si substrate. In this disseration is reported that Hf silicate films are more stable than Zr silicate films, from the metal interdiffusion point of view. On the other hand, dopant (B, As, and P) penetration is observed for HfSixO y films. However, the addition of nitrogen to the Hf - Si - O systems improves the dopant penetration properties of the resulting HfSi xOyNz films.

  14. Characterization of electron beam deposited thin films of HfO2 and binary thin films of (HfO2:SiO2) by XRD and EXAFS measurements

    International Nuclear Information System (INIS)

    Das, N.C.; Sahoo, N.K.; Bhattacharyya, D.; Thakur, S.; Kamble, N.M.; Nanda, D.; Hazra, S.; Bal, J.K.; Lee, J.F.; Tai, Y.L.; Hsieh, C.A.

    2009-10-01

    In this report, we have discussed the microstructure and the local structure of composite thin films having varying hafnia and silica compositions and prepared by reactive electron beam evaporation. XRD and EXAFS studies have confirmed that the pure hafnium oxide thin film has crystalline microstructure whereas the films with finite hafnia and silica composition are amorphous. The result of EXAFS analysis has shown that the bond lengths as well as coordination numbers around hafnium atom change with the variation of hafnia and silica compositions in the thin film. Finally, change of bond lengths has been correlated with change of refractive index and band gap of the composite thin films. (author)

  15. Endostatin (EntreMed).

    Science.gov (United States)

    Grosios, K

    2000-07-01

    EntreMed has licensed the worldwide rights to the angiogenesis inhibitor Endostatin, a 20 kDa C-terminal fragment of collagen XVIII, from the Children's Hospital of Boston, a teaching affiliate of Harvard Medical School. It is being developed as a potential cancer treatment and may also be useful in certain types of blindness and arthritis [227427]. EntreMed filed an IND for Endostatin in June 1999 [334125] and as of September 1999, phase I trials were underway [341462]. As of April 2000, the company had initiated plans for testing low doses of Endostatin in cancer patients using continuous infusion and sc administration in a further phase I study to be conducted in Europe [361594]. A phase I trial of Endostatin which will evaluate the safety and efficacy of Endostatin at a range of doses in no more than 100 cancer patients has been initiated. The trial will take place at the University of Texas MD Anderson Medical Center and the University of Wisconsin Cancer Center in Madison. The National Cancer Center will be sponsoring the trial, which is expected to be completed in late 2000. As of March 2000, there had been no serious adverse events attributable to Endostatin administration. The first report from this trial is expected in autumn 2000 [341462], [366312]. The mechanism of action for Endostatin remains unclear, although reports from the 91st AACR Meeting in April 2000 showed that recombinant human endostatin bound to a number of tropomyosin cDNAs in a library screen [362039]. In preclinical studies, repeated administration of Endostatin consistently shrank primary tumors and did not produce any drug resistance. In mice, a variety of tumors which had progressed to 1 to 2% of total body weight, regressed to microscopic, dormant lesions following Endostatin treatment [231418], [231470], [270673]. Types of cancers which respond to Endostatin include lung, skin, vascular and fibrosarcomas. Toxicology studies in cynomolgus monkeys showed that bolus injections of

  16. Correlações genotípicas, fenotípicas e de ambiente entre dez caracteres de melancia e suas implicações para o melhoramento genético Genotypic, phenotypic and environmental correlations among agronomic traits and the consequences for watermelon breeding

    Directory of Open Access Journals (Sweden)

    Maria Aldete J.F. Ferreira

    2003-09-01

    Full Text Available Foram estimadas as correlações genotípicas, fenotípicas e de ambiente entre os caracteres número de dias para o aparecimento da primeira flor feminina (FF; número de frutos por planta (NF; peso de frutos por planta (PF; cor (CP e espessura (EP da polpa; diâmetro longitudinal (DL e transversal (DT de frutos; teor de sólidos solúveis (TS; número de sementes (NS e peso de 100 sementes (PS por fruto. As populações de melancia B9, 'Charleston Gray', 'Crimson Sweet', 'New H. Midget', M7, P14 e B13, os 21 híbridos F1, em dialelo, e seus recíprocos foram avaliados em campo, de acordo com o delineamento em blocos ao acaso completos, com quatro repetições. Houve grande similaridade entre as estimativas das correlações genotípicas e fenotípicas investigadas. Foram verificadas correlações genotípicas importantes entre os caracteres NF e PF, DL e DT; entre PF e DL, DT, EP e TS e entre CP e FF, EP e TS. Tais correlações indicam que o aumento no número de frutos por planta está correlacionado com a redução do peso de frutos e do tamanho dos frutos (função de DL e DT e que o aumento no peso dos frutos está associado ao aumento no tamanho dos frutos, da espessura e teor de sólidos solúveis da polpa, assim como a polpa vermelha está relacionada à precocidade e ao aumento na espessura e no teor de sólidos solúveis da polpa. As associações indesejáveis entre os caracteres, como entre número de frutos por planta e cor da polpa e número de frutos por planta e teor de sólidos solúveis, não foram completas, indicando, portanto, a possibilidade de se obter indivíduos recombinantes a partir de populações segregantes sintetizadas através de intercruzamentos de populações contrastantes.Genotypic, phenotypic and environmental correlations were estimated among the following traits of watermelon: number of days to the appearance of the first female flower (FF; number of fruits per plant (NF; weight of fruit (PF; flesh color

  17. Lifetime embrittlement of reactor core materials

    International Nuclear Information System (INIS)

    Kreyns, P.H..; Bourgeois, W.F.; Charpentier, P.L.; Kammenzind, B.F.; Franklin, D.G.; White, C.J.

    1994-08-01

    Over a core lifetime, the reactor materials Zircaloy-2, Zircaloy-4, and hafnium may become embrittled due to the absorption of corrosion- generated hydrogen and to neutron irradiation damage. Results are presented on the effects of fast fluence on the fracture toughness of wrought Zircaloy-2, Zircaloy-4, and hafnium; Zircaloy-4 to hafnium butt welds; and hydrogen precharged beta treated and weld metal Zircaloy-4 for fluences up to a maximum of approximately 150 x 10 24 n/M 2 (> 1 Mev). While Zircaloy-4 did not exhibit a decrement in K IC due to irradiation, hafnium and butt welds between hafnium and Zircaloy-4 are susceptible to embrittlement with irradiation. The embrittlement can be attributed to irradiation strengthening, which promotes cleavage fracture in hafnium and hafnium-Zircaloy welds, and, in part, to the lower chemical potential of hydrogen in Zircaloy-4 compared to hafnium, which causes hydrogen, over time, to drift from the hafnium end toward the Zircaloy-4 end and to precipitate at the interface between the weld and base-metal interface. Neutron radiation apparently affects the fracture toughness of Zircaloy-2, Zircaloy-4, and hafnium in different ways. Possible explanations for these differences are suggested. It was found that Zircaloy-4 is preferred over Zircaloy-2 in hafnium-to- Zircaloy butt-weld applications due to its absence of a radiation- induced reduction in K IC plus its lower hydrogen absorption characteristics compared with Zircaloy-2

  18. The energy landscape of glassy dynamics on the amorphous hafnium diboride surface

    International Nuclear Information System (INIS)

    Nguyen, Duc; Girolami, Gregory S.; Mallek, Justin; Cloud, Andrew N.; Abelson, John R.; Lyding, Joseph; Gruebele, Martin

    2014-01-01

    Direct visualization of the dynamics of structural glasses and amorphous solids on the sub-nanometer scale provides rich information unavailable from bulk or conventional single molecule techniques. We study the surface of hafnium diboride, a conductive ultrahigh temperature ceramic material that can be grown in amorphous films. Our scanning tunneling movies have a second-to-hour dynamic range and single-point current measurements extend that to the millisecond-to-minute time scale. On the a-HfB 2 glass surface, two-state hopping of 1–2 nm diameter cooperatively rearranging regions or “clusters” occurs from sub-milliseconds to hours. We characterize individual clusters in detail through high-resolution (<0.5 nm) imaging, scanning tunneling spectroscopy and voltage modulation, ruling out individual atoms, diffusing adsorbates, or pinned charges as the origin of the observed two-state hopping. Smaller clusters are more likely to hop, larger ones are more likely to be immobile. HfB 2 has a very high bulk glass transition temperature T g , and we observe no three-state hopping or sequential two-state hopping previously seen on lower T g glass surfaces. The electronic density of states of clusters does not change when they hop up or down, allowing us to calibrate an accurate relative z-axis scale. By directly measuring and histogramming single cluster vertical displacements, we can reconstruct the local free energy landscape of individual clusters, complete with activation barrier height, a reaction coordinate in nanometers, and the shape of the free energy landscape basins between which hopping occurs. The experimental images are consistent with the compact shape of α-relaxors predicted by random first order transition theory, whereas the rapid hopping rate, even taking less confined motion at the surface into account, is consistent with β-relaxations. We make a proposal of how “mixed” features can show up in surface dynamics of glasses

  19. Correlação entre ansiedade e performance comunicativa Correlation between anxiety and communicative performance

    Directory of Open Access Journals (Sweden)

    Anna Alice Figueirêdo de Almeida

    2011-12-01

    Full Text Available OBJETIVO: Investigar a correlação entre ansiedade-traço, ansiedade-estado e parâmetros vocais. MÉTODOS: Participaram 24 adultos, 12 homens e 12 mulheres, com idades entre 19 e 42 anos e sem antecedentes psiquiátricos. O escore do Inventário de Ansiedade Traço-Estado (IDATE, principalmente o Ansiedade-Traço, possibilitou a divisão dos participantes em dois grupos: baixa ansiedade (BA e alta ansiedade (AA. Foram avaliados parâmetros psicológicos (IDATE e vocais (auto-avaliação por questionário de sinais e sintomas vocais, QSSV; protocolo de Qualidade de Vida em Voz - QVV; avaliação perceptivo-auditiva-visual do comportamento vocal com a descrição de parâmetros de voz, fala e corpo; e análise acústica. O material de fala analisado foi a emissão sustentada da vogal /a/, contagem de números e um discurso sobre momentos de maior ansiedade ao longo da vida. RESULTADOS: Quanto maior o traço de ansiedade indicado pelo IDATE, maior a evidência de ansiedade na fala encadeada e no discurso; quanto mais agudo o pitch da voz, maior o comprometimento da articulação da fala, da coordenação pneumofono-articulatória, da movimentação corporal e da expressão facial. Quanto maior o estado de ansiedade, maior a evidência de ansiedade em diversos parâmetros do discurso, com desequilíbrio na ressonância vocal, comprometimento na modulação, na articulação da fala e na expressão facial. CONCLUSÃO: O traço e o estado de ansiedade diferenciaram o comportamento comunicativo dos indivíduos, envolvendo modificações no corpo, na fala e na voz.PURPOSE: To investigate the possible existing correlations between trait anxiety, state anxiety, and vocal parameters. METHODS: Participants were 24 adult subjects, 12 men and 12 women, with ages between 19 and 42 years, with no psychiatric history. The score in the State-Trait Anxiety Inventory (STAI, especially the STAI-Trait, enabled the division of participants into two groups: low

  20. Correlation among methods to evaluate sperm membrane integrity of bovine cryopreserved sperm Correlação entre métodos de avaliação da integridade da membrana plasmática do espermatozóide bovino criopreservado

    Directory of Open Access Journals (Sweden)

    Thaíse Silva Passos

    2009-09-01

    Full Text Available It were established correlations among methods of sperm plasmatic membrane evaluation, by analyzing cryopreserved semen of five Nelore bulls, within three replicates / bull. After thawing at 37°C/30 seconds, there were assessed motility (%, concentration (x106, morphology (% and membrane integrity. To evaluate membrane integrity, hypoosmotic test (HOS, fluorescence (FLU and eosin/nigrosin (EN were used. Data were submitted to Pearson´s correlation analysis. According to the results, there was correlation between fluorescence vs eosin/nigrosin (r = 0.74; p<0.0013, fluorescence vs hypoosmotic test (r = 0.71; p<0.0029 and eosin/nigrosin vs hypoosmotic test (r = 0.59; p<0.0202. There was also correlation among motility and fluorescence (r = 0.70; p<0.0036, hypoosmotic test (r = 0.78; p<0.0006 and eosin/nigrosin (r = 0.52; p<0.0436. We conclude that the three methods were efficacious in evaluating plasmatic membrane integrity of bovine frozen-thawed spermatozoa, and each laboratory could make its choice according to disposable equipments.O objetivo, com este trabalho, foi verificar a correlação entre métodos de avaliação da integridade da membrana plasmática (IMP, no sêmen congelado comercial de cinco touros da raça Nelore, com três repetições por animal. Após o descongelamento a 37C/30 segundos, foram analisadas as variáveis motilidade (%, concentração (x106/ml, morfologia (% e IMP. Para a avaliação da IMP, foram usados o teste hiposmótico (HOS, fluorescência (FLU e eosina/nigrosina (EN, e contadas 100 células/lâmina. Os dados foram submetidos à análise de correlação de Pearson. Houve correlação entre as técnicas de fluorescência vs eosina/nigrosina (r = 0,74; p<0,0013, fluorescência vs teste hiposmótico (r = 0,71; p<0,0029 e correlação de média intensidade entre eosina/nigrosina vs teste hiposmótico (r = 0,59; p<0,0202. Houve correlação entre motilidade e fluorescência (r = 0,70; p<0,0036; teste hiposm

  1. Correlações entre componentes anatômicos, químicos e digestibilidade in vitro da matéria seca de gramíneas forrageiras Chemical and anatomical traits, and in vitro dry matter digestibility correlations in forage grasses

    Directory of Open Access Journals (Sweden)

    Domingos Sávio Campos Paciullo

    2001-06-01

    Full Text Available Lâminas foliares e segmentos de colmo das gramíneas forrageiras capim-braquiária (Brachiaria decumbens, capim-gordura (Melinis minutiflora e capim-bermuda Tifton 85 (Cynodon sp foram amostradas em dois níveis de inserção no perfilho (inferior e superior, em duas idades (momento da exposição da lígula da folha e 20 dias após e em duas estações de crescimento (verão e outono. Amostras dos segmentos de colmo e lâminas foliares foram submetidas à determinação de sua composição química, composição anatômica e digestibilidade in vitro. Após obtenção dos dados, foram estabelecidas as correlações entre os componentes químicos e anatômicos e entre estes e a DIVMS, na lâmina, no colmo e no agrupamento dos dados das duas frações. A espessura da parede celular foi a característica anatômica a se correlacionar mais fortemente com todos os componentes químicos, independente da fração considerada. Suas correlações foram positivas com os teores de fibra em detergente neutro, fibra em detergente ácido e lignina e negativa com os de proteína bruta. A proporção de mesofilo se correlacionou positivamente com os teores de proteína bruta e negativamente com os de fibra em detergente ácido, enquanto a proporção de esclerênquima apresentou correlação positiva com os teores de fibra em detergente neutro. Os componentes químicos se correlacionaram fortemente entre si e com a DIVMS. Entre as características anatômicas, somente a espessura da parede celular mostrou correlação significativa com a DIVMS, independente da fração. O mesofilo se correlacionou positivamente e o xilema negativamente com a DIVMS, respectivamente, na lâmina e no colmo.Leaf blades and stem segments at two stages of development (day of leaf ligule exposure and 20 days thereafter and two insertion levels on tillers (lower and upper of signalgrass (Brachiaria decumbens, molassesgrass (Melinis minutiflora and tifton 85 bermudagrass (Cynodon sp

  2. Correlações entre características estruturais e valor nutritivo de perfilhos em pastos de capim-braquiária diferidos e adubados com nitrogênio Correlations among structural characteristics and nutritional value of tillers on deferred and nitrogen-fertilized signalgrass pastures

    Directory of Open Access Journals (Sweden)

    Virgilio Mesquita Gomes

    2010-09-01

    Full Text Available Perfilhos de Brachiaria decumbens cv. Basilisk foram amostrados em pastos diferidos e adubados com nitrogênio (0, 40, 80 e 120kg/ha de N com o objetivo de avaliar correlações entre suas características estruturais, morfológicas e de valor nutritivo. Foi adotado o delineamento em blocos ao acaso, com três repetições. Não foi observada correlação entre número e peso de perfilhos. Porém, houve correlação positiva do peso do perfilho com comprimento do colmo, número de folha morta e percentual de colmo verde e negativa com número de folhas verdes e percentual de folha verde. As correlações entre número de perfilhos foram positivas com os percentuais de proteína bruta, fibra em detergente neutro potencialmente digestível e matéria seca potencialmente digestível e negativa para fibra em detergente neutro e fibra em detergente neutro indigestível. De outra forma, o peso dos perfilhos apresentou correlação positiva com os teores de fibra em detergente neutro e fibra em detergente neutro indigestível e associação negativa com o percentual de matéria seca potencialmente digestível. O negativa com número de folhas verdes apresentou correlações positivas com os teores de proteína bruta, fibra em detergente neutro potencialmente digestível e matéria seca potencialmente digestível, bem como correlações negativas com os percentuais de fibra em detergente neutro e fibra em detergente neutro indigestível. A composição morfológica e o valor nutritivo de perfilhos de Brachiaria decumbens cv. Basilisk foram determinados por suas características estruturais. Em pastos diferidos de Brachiaria decumbens cv. Basilisk ocorreu compensação entre tamanho e valor nutritivo de perfilhos.Brachiaria decumbens cv. Basilisk tillers were sampled on deferred and nitrogen-fertilized pastures (0, 40, 80 and 120kg/ha of N, in order to evaluate correlations among its structural characteristics, morphological composition and nutritional

  3. Correlação linear e espacial entre a produtividade de forragem, a porosidade total e a densidade do solo de Pereira Barreto (SP Linear and spatial correlations between forage yield, total porosity and bulk density in Pereira Barreto, Brazil

    Directory of Open Access Journals (Sweden)

    Cesar Gustavo da Rocha Lima

    2007-12-01

    Full Text Available Em relação aos sistemas de manejo adotados pelo homem, a porosidade total e a densidade do solo são atributos ativamente alterados, refletindo decisivamente sobre a produtividade vegetal agrícola. No ano agrícola de 2005, na Fazenda Bonança, no município de Pereira Barreto, Estado de São Paulo, Brasil, foram analisadas a produtividade de forragem do milho outonal (MSF no sistema plantio direto irrigado, a porosidade total (PT e a densidade do solo (DS em profundidade, em um Latossolo Vermelho distrófico. O objetivo foi estudar a variabilidade e as correlações lineares e espaciais entre os atributos da planta e do solo, visando selecionar um indicador da qualidade física do solo de boa representatividade para produtividade da forragem. Foi instalada a malha geoestatística, para coleta de dados do solo e planta, contendo 125 pontos amostrais, numa área de 2.500 m². Os atributos estudados, além de não terem variado aleatoriamente, apresentaram variabilidade dos dados entre média e baixa e seguiram padrões espaciais bem definidos, com alcance entre 6,8 e 23,7 m. Por sua vez, a correlação linear entre o atributo da planta e os do solo, em razão do elevado número de observações, foi baixa. As observações de melhor correlação com a MSF foram a DS1 e a PT1. Entretanto, do ponto de vista espacial, houve excelente correlação inversa entre a MSF e a DS1, assim como entre a DS1 e a PT1. Nos sítios onde a DS1 aumentou (1,45-1,64 kg dm-3 a MSF variou entre 11.653 e 14.552 kg ha-1; já naqueles onde diminuiu (1,35-1,45 kg dm-3 a MSF, ficou entre 14.552 e 17.450 kg ha-1. Portanto, a densidade global, avaliada na camada de 0-0,10 m (DS1, apresentou-se como satisfatório indicador da qualidade física do solo de Pereira Barreto (SP, quando destinado à produtividade de forragem do milho outonal.Total porosity and bulk density are strongly affected by soil management, which is reflects directly in agricultural productivity. In 2005

  4. Correlações entre a maturidade da fibra e outros caracteres econômicos do algodoeiro Simple correlations between fiber maturity and economic characteristics in cotton

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    Nélson Paulieri Sabino

    1976-07-01

    Full Text Available As características da fibra - comprimento, uniformidade, índice Micronaire (finura, resistência Pressley -, a resistência do fio, assim como a porcentagem de fibra, peso de um capulho, peso de 100 sementes e a produção, foram correlacionados com a maturidade da fibra, determinada pelo fibrógrafo digital. Para tanto foram utilizados os dados de 12 ensaios regionais de variedades instalados no ano agrícola de 1970/71, e de 13 ensaios instalados em 1971/72, em diferentes locais do Estado de São Paulo. Esses ensaios, em quadrado latino 6x6, forneceram 72 pares de valores no primeiro ano e 78 pares no segundo, para os cálculos dos coeficientes de correlação. Estes foram computados por ano e por variedade. Valores médios foram estimados através da transformação Z de Fisher. Houve variações sensíveis no valor dos coeficientes entre anos dentro de variedades e entre variedades dentro de ano. As estimativas médias foram significativas, com exceção da resistência da fibra, da resistência do fio e da porcentagem de fibra. Houve falta de homogeneidade nos casos do índice Micronaire e da uniformidade de comprimento. No ano de 1971/72, de condições piores para o algodoeiro, os coeficientes de correlação alcançaram valores mais altos.Simple correlations between maturity indices determined by the digital fibrograph and the characteristics of fiber length, uniformity, Micronaire, Pressley (1/8 gauge, yarn strength, mean boll weight, mean weight of 100 seeds, percentage of fiber, and yield were studied. Data of 12 experiments of regional variety tests planted in 1970/71 and of 13 experiments planted in 1971/72 in different regions of the State of São Paulo were used. These experiments delined in 6x6 latin squares yielded 72 pairs of data in the first year and 78 in the second year. Correlation coefficients were computed by variety within years and mean estimates obtained through Fisher's Z transformation. Large variations of the

  5. Relação entre indícios de disgrafia funcional e desempenho acadêmico Correlation between indication of disgraphy and scholarship performance

    Directory of Open Access Journals (Sweden)

    Sônia das Dores Rodrigues

    2009-06-01

    Full Text Available OBJETIVO: avaliar a relação entre sinais indicativos de disgrafia e desempenho acadêmico. MÉTODOS: foram incluídas no estudo 25 crianças, matriculadas na 3ª. série do ensino fundamental de uma escola pública da Região Metropolitana de Campinas/SP, sem histórico de lesão cerebral e/ou déficit intelectual. Quanto à idade, 21 tinham nove anos e quatro tinham dez anos; 12 eram do sexo masculino. A avaliação foi realizada por meio da Escala de Disgrafia (Lorenzini, 1993 e do Teste de Desempenho Escolar (TDE (Stein, 2003. RESULTADOS: seis crianças apresentaram sinais indicativos de disgrafia. A maioria dos alunos teve desempenho acadêmico classificado como inferior em escrita (15/25 e em aritmética (10/25. As crianças com indícios de disgrafia (6/25 tiveram pior desempenho em escrita e aritmética no TDE, quando comparado às demais crianças, porém essa diferença não foi estatisticamente significativa. CONCLUSÃO: conclui-se que, neste grupo, não foi possível estabelecer a relação entre baixo desempenho acadêmico com escrita disgráfica, uma vez que tal dificuldade também foi identificada também entre as crianças consideradas não disgráficas.PURPOSE: to evaluate the relationship between indicative signals of written difficulties and cadmic performance. METHODS: twenty five children, students from the 3rd grade in the elementary education school of a public school in the metropolitan area of Campinas/SP took part in this study (12 boys, with age varying between 9 and 10. The tools used for evaluation were the scale of written difficulties (Lorenzini, 1993 and the test of school performance (Stein, 2003. RESULTS: considering the group performance, it was verified that a great number of students had written academic (15/25 and arithmetic (10/25 difficulties. The children with indicative signals of written difficulties (6/25 had inferior performance in writing and arithmetic, when compared to the ones who did not have

  6. Correlação entre hipoxemia moderada e função muscular esquelética periférica na doença pulmonar obstrutiva crónica - Estudo-piloto Correlation between mild hypoxaemia and limb skeletal muscle function in chronic obstructive pulmonary disease - Pilot study

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    Sérgio Leite Rodrigues

    2008-12-01

    Full Text Available Introdução: A capacidade de exercício em portadores de DPOC depende da gravidade da limitação ao fluxo aéreo, do grau de hipoxemia e da função muscular esquelética. Nesses doentes, a atrofia e a fraqueza da musculatura periférica são consideradas consequências sistémicas da DPOC e estão associadas à redução da capacidade de exercício. Objectivos: Investigar a possível correlação entre hipoxemia moderada e o comprometimento muscular periférico na DPOC. Doentes e métodos: Dez doentes encaminhados ao Programa de Reabilitação Pulmonar do Hospital Universitário de Brasília foram incluídos neste estudo. A função pulmonar foi avaliada por espirometria, gasometria arterial e avaliação funcional pelo teste de caminhada de seis minutos, sinal electromiográfico e força de deltóide e quadricípetes. Resultados: As correlações entre PaO2 e a força quadricíptica (r2 = 0,61 e p = 0,007 e a distância percorrida no TC6 (r2 = 0,96 e p = 0,001 foram positivas e significativas. Houve correlação negativa e significativa entre PaO2 e a frequência mediana de quadricípetes (r2 = -0,42 e p = 0,04. Observámos também correlação significativa entre força de quadricípetes e o TC6 (r2 = 0,67 e p = 0,001. Assim como houve correlação negativa e significativa entre a frequência mediana de quadricípetes, e o TC6 (r2 = -0,42 e p = 0,04. Não encontrámos correlação significativa entre a PaO2 e força ou frequência mediana do músculo deltóide. Conclusão: A PaO2 tem correlação importante e significativa com variáveis de função muscular periférica. A hipoxemia moderada e a disfunção muscular periférica precoce possuem como principal impacto negativo a deterioração da capacidade funcional de portadores de DPOC.Rationale: Exercise capacity in COPD patients depends on the degree of airflow obstruction, the severity of the hypoxaemia and skeletal muscle function. Muscle atrophy and weakness are considered systemic

  7. Relações entre desempenho escolar e orientações motivacionais Relations between school performance and motivational orientations

    Directory of Open Access Journals (Sweden)

    Selma de Cássia Martinelli

    2009-04-01

    Full Text Available O objetivo deste estudo foi investigar as relações entre desempenho escolar de alunos do ensino fundamental e suas orientações motivacionais. Participaram 150 estudantes, entre 9 e 12 anos de idade, de uma escola pública do Estado de São Paulo, que cursavam a 3ª e 4ª séries do ensino fundamental. Os resultados revelaram que na terceira série houve uma correlação significativa e negativa entre motivação extrínseca e desempenho escolar, ou seja, quanto menor o desempenho escolar maior a motivação extrínseca. No que diz respeito à motivação intrínseca e o desempenho escolar, as variáveis não apresentaram correlação significativa. Na 4ª série houve uma correlação significativa e negativa entre motivação extrínseca e desempenho escolar, ou seja, quanto menor o desempenho escolar maior a motivação extrínseca. No que diz respeito à motivação intrínseca e o desempenho escolar as variáveis apresentaram correlação significativa e positiva, indicando que quanto maior o desempenho maior a motivação intrínseca.The intent of this research was to investigate if a relationship exists between the school performance and the motivational orientations from elementary students. Participants were 150 male and female elementary school children, aged between 9 and 12 years of two public schools from Sao Paulo State. The results indicated that in the third-grade there was a negative and significant correlation between extrinsic motivation and the school performance, that is, the lower the school performance the higher the extrinsic motivation. For the intrinsic motivation and school performance, variables showed no significant correlation and extrinsic motivation and in the fourth-grade, the results showed a significant and positive correlation. For the fourth-grade, there was a negative and significant correlation between extrinsic motivation and school performance, that is, the lower the school performance the higher the

  8. Contribution towards ALD and MOCVD of rare earth oxides and hafnium oxide. From precursor evaluation to process development and thin film characterization

    International Nuclear Information System (INIS)

    Xu, Ke

    2013-01-01

    elements for ALD applications. A possible synthesis route is the salt metatheses route. It could be expected that the monodentate guanidine ligand would provide increased reactivity towards water, where the bulky guanidine ligands will shield the RE center providing self-limiting growth behavior. In Chapter 4 and 7, ALD of rare earth oxides and hafnium oxide using corresponding guanidinate precursors are in detail investigated. According to the measurements, these processes are true ALD processes with broad ALD windows, high growth per cycle in the saturated area. Furthermore, the rare earth guanidinate and hafnium guanidinate precursors exhibit matching ALD window in the temperature range of 200 - 225 C. This motivated us to deposite trinary oxide thin films (HfREOx) using corresponding precursor combinations.

  9. Correlação entre o índice de massa corporal e os indicadores antropométricos de distribuição de gordura corporal em adultos e idosos Correlation between body mass index and body fat distribution anthropometric indices in adults and the elderly

    Directory of Open Access Journals (Sweden)

    Lilian Ramos Sampaio

    2005-02-01

    Full Text Available OBJETIVO: O objetivo deste trabalho foi avaliar a correlação entre o índice de massa corporal e indicadores antropométricos de distribuição de gordura em adultos e idosos. MÉTODOS: Trata-se de um estudo transversal, constituído por 634 indivíduos (316 adultos e 318 idosos de ambos os sexos, atendidos nos ambulatórios do Hospital das Clínicas da Universidade Federal da Bahia (Salvador, BA. Mediram-se em cada indivíduo: peso, altura, pregas cutâneas triciptal e subescapular, circunferências de quadril e cintura, segundo técnicas propostas por Lohman, em 1988. Utilizou-se o teste de correlação de Pearson para avaliar a correlação entre o índice de massa corporal e os indicadores antropométricos de distribuição de gordura. RESULTADOS: As correlações entre o índice de massa corporal e a circunferência da cintura nos dois grupos etários do sexo masculino foram: de adultos (r = 0,93; pOBJECTIVE: This cross-sectional study investigates the correlation between the body mass index and the fat distribution anthropometric indices in adults and the elderly. METHODS: Upon ambulatory visits to the Medical School Hospital of the Federal University of Bahia (Salvador, Bahia, Brazil, 634 male and female patients (316 adults and 318 elderly subjects were measured individually, to determine weight, height, triceps and subscapular skinfold thicknesses, and waist and hip circumferences, according to Lohman's guidelines, 1988. Pearson's correlation test was used to get the correlation, in this sample, between body mass index and fat distribution anthropometric indices. RESULTS: The correlations between body mass index and waist in both age groups for male were: adults (r = 0.93; p<0.001 and elderly (r = 0.89; p<0.001. For the female groups, these correlations were: adults (r = 0.93; p<0.001 and elderly (r = 0.86; p<0.001. The correlation between body mass index and waist-to-hip ratio was smaller, but statistically significant, between these

  10. Correlación entre actitud hacia homosexualidad femenina y masculina en estudiantes de Medicina/ Correlation between the attitude toward female and male homosexuality in medical

    Directory of Open Access Journals (Sweden)

    Adalberto Campo-Arias

    2017-04-01

    Full Text Available Este artículo es resultado de una investigación cuyo objetivo fue explorar la correlación cuantitativa entre homofobia y lesbofobia en estudiantes de medicina de una universidad de Bogotá, Colombia. El estudio transversal se llevó a cabo con estudiantes de medicina mayores de 18 años. La homofobia y la lesbofobia se midieron con la Escala para Actitud hacia Gais y Lesbianas (ATGL. La ATGL se compone de dos escalas de diez ítems: Escala para Actitud hacia Hombres Gais (ATG y la Escala para Actitud hacia Mujeres Lesbianas (ATL. La correlación entre puntuaciones para homofobia y lesbofobia se calculó con coeficiente de Pearson (r. Se planteó la hipótesis de que homofobia y lesbofobia eran diferentes construcciones si la correlación entre las escalas era inferior a 0,60. Un total de 359 estudiantes de medicina participaron en la investigación, la media para la edad fue de 20,2 años (DE=1,9, y el 59,1% eran mujeres. Las puntuaciones en la ATG (alfa de Cronbach de 0,85 se observaron entre 10 y 50, con una media de 27,9 (DE=8,1 y en la ATL (alfa de Cronbach de 0,73 entre 10 y 45, con media de 24,8 (DE=6,8. La correlación entre homofobia (ATG y lesbofobia (ATL fue r=0,64 (p<0,001. Se concluye que la ATG y ATL muestran correlación altamente significativa, lo que sugiere que homofobia y lesbofobia no son constructos completamente diferentes y podrían incluirse en el concepto general de prejuicio sexual. Otras investigaciones deben corroborar el presente hallazgo.

  11. Status of computational and experimental correlations for Los Alamos fast-neutron critical assemblies; Correlation entre les calculs et les experiences sur les ensembles critiques a neutrons rapides de Los Alamos; Sostoyanie vychislitel'nykh i ehksperimental'nykh korrelyatsij dlya Los-Alamosskoj kriticheskoj sistemy na bystrykh nejtronakh; Conjuntos criticos de neutrones rapidos de Los Alamos; correlacion entre resultados calculados y experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, G E [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1962-03-15

    les reacteurs ainsi qu'a celle des methodes de calcul, permettent de connaitre de mieux en mieux les caracteristique s d'une classe d'ensembles critiques a neutrons rapides. Cette classe comprend maintenant des montages a {sup 233}U, en geometrie spherique, sans reflecteur ou avec un reflecteur constitue d'une couche epaisse d'uranium. L'auteur presente des correlations directes parmi les donnees experimentales , pour montrer qu'il existe a priori la possibilite de bonnes correlations avec les resultats des calculs. La sensibilite des spectres calcules et des dimensions critiques aux modeles de transport neutronique (approximations du transport et hypothese de linearite) et aux approximations arithmetiques (hypothese de la segmentation angulaire et representations multigroupes) est presentee pour divers ensembles critiques afin d'aider a etablir les details des calculs indispensables. La comparaison entre l'experience et les previsions porte sur les indices spectraux et les dimensions critiques, les durees de vie des neutrons et les rapports relatifs aux neutrons retardes. (author) [Spanish] La puesta en servicio de nuevos conjuntos criticos y el perfeccionamiento de los metodos de medicion exigen una revision periodica de la correlacion entre los resultados calculados y los experimentales. Dados los problemas particularmente delicados que plantea la medicion de indices espectrales absolutos y dada tambien la necesidad de comprobar los calculos mas alla de las simples dimensiones criticas, conviene hacer hincapie en las caracterizaciones de los espectros neutronicos. El continuo perfeccionamient o ds las mediciones de indices espectrales, unido a la creciente precision de los datos microscopicos relativos a los materiales utilizados en los conjuntos criticos y en los detectores asi como la de los metodos de calculo contribuyen a un mejor conocimiento de las caracteristicas de un grupo de conjuntos criticos de neutrones rapidos. Este grupo compiende actualmente los

  12. Nano-crystals of cerium–hafnium binary oxide: Their size-dependent structure

    Energy Technology Data Exchange (ETDEWEB)

    Raitano, Joan M. [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States); Khalid, Syed [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973 (United States); Marinkovic, Nebojsa [Chemical Engineering Department, Columbia University, 500 W 120th St, Mudd 801, New York, NY 10027 (United States); Chan, Siu-Wai, E-mail: sc174@columbia.edu [Department of Applied Physics and Applied Mathematics, Materials Science and Engineering Program, Columbia University, New York, NY 10027 (United States)

    2015-09-25

    Highlights: • (1 − x)CeO{sub 2}–xHfO{sub 2} was precipitated (0 < x < 1) and calcined in air. • For x ⩽ 0.14, crystallites ⩽140 nm in size exhibit only the fluorite structure. • This low hafnia solubility is attributable to no auto-reduction (Ce{sup 3+} = 0). • The low solubility is also due to the high temperature required for homogenization. • Coarsening is lessened as Hf{sup 4+} ions slow cation diffusion in these crystallites. - Abstract: Cerium oxide (CeO{sub 2}, “ceria”) and hafnium oxide (HfO{sub 2}, “hafnia”) were aqueously co-precipitated and subsequently calcined to allow for homogenization. The size of the (1−x)CeO{sub 2}–xHfO{sub 2} crystallites, determined by the Scherrer equation, varied from 140 nm for x = 0 to 15 nm for x = 0.73. For x ⩽ 0.14, only cubic structures are visible in X-ray diffractograms, and the lattice parameters are consistent with the values expected for structurally cubic solid solutions of hafnia in ceria. At x = 0.26, tetragonal and monoclinic phases nucleated with the former not being observed in the bulk phase diagram for ceria–hafnia. Therefore, the solubility limit of the cubic structure is between x = 0.14 and x = 0.26 for 40–61 nm crystallites, the sizes of these respective compositions. More specifically, for the 40 nm crystallites of x = 0.26 (1 − x)CeO{sub 2}–xHfO{sub 2}, 15% of the hafnia remains in a structurally cubic solid solution with ceria based on the observed cubic lattice parameter. The compositional domain for the cubic fluorite structure in this study is narrower than other nanostructured (1 − x)CeO{sub 2}–xHfO{sub 2} studies, especially studies with crystallite sizes less than 10 nm, but wider than observed in the bulk and helps to expand the size regime over which the relationship between crystallite size and phase stability is known. The extent of this cubic-structure domain is mainly attributable to the intermediate crystallite size and the roughly zero Ce{sup 3

  13. Correlação entre WISC e rendimento escolar na escola pública e na escola particular Correlation between WISC and school performance in public and private schools

    Directory of Open Access Journals (Sweden)

    Álida Dal Vesco

    1998-01-01

    Full Text Available O trabalho compara resultados do WISC com rendimento escolar , no sentido de correlacionar medidas psicométricas de inteligência com critérios de rendimento escolar, a fim de aperfeiçoar a capacidade diagnóstica e preditiva do teste. Participaram 20 alunos (10 de escola pública e 10 de escola particular, de 5ª a 8ª séries, com idade entre 8,7 a 13,2 anos, do grupo considerado com um bom desempenho. Não houve correlação significativa entre resultados do WISC e rendimento escolar. Comparando escolas, os alunos da rede particular tiveram pontuações significativamente melhores em Compreensão [t(2,18= 2,78; pThis study compared performance on the WISC with school grades in na attempt to improve the diagnostic and predictive capacity of the test in Brazil. Twenty students (10 from a public school and 10 from a private school, attending the fifth through the eighth grade, 8.7 to 13.2 years old, from a group classified as having high performance participated in the study. There was no significant correlation between the WISC results and school performance. Comparing the schools, the students from the private school network obtained scores significantly higher in Comprehension, Vocabulary, and Coding. However, no significant difference was found with respect to grades. This finding was explained based on the peculiarities of school programs.

  14. Correlações entre características físico-químicas e sensoriais em suco de maracujá-amarelo (Passiflora edulis var. flavicarpa durante o armazenamento Correlation between physico-chemical and sensory characteristcs of yellow passin fruit juice over storaging time

    Directory of Open Access Journals (Sweden)

    Delcio Sandi

    2003-12-01

    Full Text Available Foram estudadas possíveis correlações entre características físicas, químicas e sensoriais em suco de maracujá-amarelo (Passiflora edulis var. flavicarpa submetido à pasteurização, durante o armazenamento por 120 dias, sob duas temperaturas (25 ± 5ºC e 5 ± 1ºC. As características físicas e químicas relacionadas a cor, parâmetros "L" (luminosidade, "a" (intensidade de vermelho e verde e "b" (intensidade de amarelo e azul de Hunter, os açúcares redutores e não-redutores (sacarose, glucose e frutose, os compostos voláteis (butirato de etila, butirato de hexila, caproato de etila e caproato de hexila e furfural foram correlacionadas com características sensoriais (homogeneidade da cor, cor laranja, aroma característico, aroma floral, aroma doce, sabor característico, sabor estranho, sabor oxidado, sabor cozido, gosto doce e gosto amargo obtidas por Análise Descritiva Quantitativa. As correlações entre os parâmetros de cor e as características sensoriais de homogeneidade da cor e cor laranja foram baixas. Entretanto, o aumento da cor laranja foi proporcional ao aumento do valor "a" e inversamente proporcional aos valores "L" e "b". Correlações importantes foram observadas entre os compostos voláteis e sabor característico e aroma característico, aroma floral e aroma doce; furfural e sabor oxidado, sabor cozido e sabor estranho. Quanto aos açúcares redutores e não-redutores, enquanto observaram-se correlações significativas entre os teores de sacarose e o aroma doce, aroma floral, sabor característico e gosto doce, correlações significativas e positivas foram observadas entre os açúcares redutores e o sabor estranho e gosto amargo. De acordo com nossas observações, o uso de métodos instrumentais pode ser indicado, como a avaliação do escurecimento por meio de parâmetros colorimétricos de cor, sendo o valor "a" de Hunter, o melhor indicado.Physical-chemistry and sensory quality characteristics

  15. Relação entre homicídios e indicadores econômicos em São Paulo, Brasil, 1996 Correlation between homicide rates and economic indicators in São Paulo, Brazil, 1996

    Directory of Open Access Journals (Sweden)

    Rita Barradas Barata

    2000-02-01

    Full Text Available Cerca de 30% dos óbitos por causas externas violentas no Brasil são decorrentes de homicídios. Tradicionalmente, a violência tem sido relacionada a problemas sociais maiores, tais como pobreza. Contudo, recentemente, tem-se observado uma correlação positiva entre maior renda e aumento das taxas de homicídio, de forma que muitos pesquisadores passaram a considerar as desigualdades sociais, mais do que a pobreza, como explicação para as epidemias de violência. O objetivo do presente trabalho foi verificar a correlação entre a urbanização, a pobreza e a desigualdade econômica e as taxas de homicídio no Estado de São Paulo, Brasil, em 1996. Para cada município do Estado foram obtidas, a partir do censo demográfico, informações sobre o tamanho, a renda mensal média dos chefes de família, a distribuição de renda e o índice de Gini. As taxas de homicídio foram calculadas para cada município a partir dos dados oficiais. Foram realizadas análises de correlação e cálculos de riscos relativos com intervalos de confiança de 95%. As taxas de homicídio apresentaram aumento diretamente proporcional ao tamanho dos municípios, variando de 6,96 (por 100 000 habitantes, em municípios com menos de 10 000 habitantes, a 55,54, em municípios com mais de um milhão de habitantes; o risco relativo variou de 1,35 a 7,98. Os resultados mostraram que apenas para o grupo de municípios com renda média mensal acima de 3,11 salários mínimos e coeficiente de Gini acima de 0,50 houve correlação significativa com o tamanho da população. A correlação entre as taxas de homicídio e a razão de rendas entre os percentis 90 e 20 da população mostrou-se forte, direta e significativa. É necessário aprofundar a análise dos determinantes macrosociais da violência, buscando identificar indicadores de desigualdade que forneçam elementos para a formulação de estratégias de saúde pública.Around 30% of the deaths due to violent causes

  16. CONVERSION OF D-XYLOSE INTO FURFURAL WITH ALUMINUM AND HAFNIUM PILLARED CLAYS AS CATALYST

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    WILLIAM CORTÉS

    2013-01-01

    Full Text Available El proceso industrial utilizado para la producción de furfural es la deshidratación de pentosas, la cual se lleva a cabo por medio de ácidos minerales, altamente corrosivos y contaminantes como catalizadores. Debido a los efectos ecológicos y toxicológicos asociados a este proceso, y a la dificultad en la separación del producto, el desarrollo de nuevos catalizadores sólidos ácidos ha tenido una significativa expansión en los últimos años. El presente trabajo de investigación se enfocó en la producción de furfural a partir de D-xilosa empleando como catalizadores sólidos ácidos, arcillas pilarizadas con aluminio y hafnio. Después de 4 h de reacción a temperaturas entre 140 y 170 °C, los resultados evidenciaron una conversión entre el 50 y el 80%, mientras que los niveles de selectividad alcanzados estuvieron entre el 40 y el 65%. Finalmente, la estabilidad de los catalizadores fue evaluada por medio de un tratamiento térmico, antes de usarlo de nuevo. En cuatro reacciones consecutivas no fue observada una disminución significativa en la selectividad. En conclusión, las arcillas pilarizadas evidencian ser catalizadores activos, selectivos y estables para la deshidratación de pentosas.

  17. Correlação clinica entre a mielopatia cervical e o índice de Torg Correlation between the clinic and the index of cervical myelopathy Torg

    Directory of Open Access Journals (Sweden)

    Agnaldo Rogério Lozorio

    2012-01-01

    Full Text Available OBJETIVO: A mielopatia cervical é uma disfunção da medula espinhal relacionada a degeneração típica do envelhecimento, cuja patologia se relaciona com a isquemia e compressão da medula. Muitos são os problemas clínicos apresentados por portadores de mielopatia, nos casos mais graves este acometimento pode levar a para ou tetraplegia quando não tratado. Devido a patologia primária desta doença ser causada por compressão gerando isquemia medular, julgamos poder existir uma correlação entre o grau de compressão e clínica dos pacientes portadores de mielopatia cervical, porém não encontramos nenhum estudo na literatura que realizou esta correlação, por existir esta dúvida na literatura é que objetivamos em nosso estudo analisar a correlação entre o grau do comprometimento clínico dos pacientes com mielopatia cervical e o índice de Torg. MÉTODOS: Estudo prospectivo, de caráter descritivo, avaliados 46 pacientes, realizado mensuração radiográfica do índice de Torg e análise clínica através da escala de JOA e Nurick. RESULTADOS: Dos 46 pacientes, 100% apresentaram Torg OBJECTIVE: Cervical myelopathy is a spinal cord dysfunction related to degeneration typical of aging. Its primary pathology is related to ischemia and spinal cord compression. Patients with myelopathy present many clinical problems; more severe cases may lead to quadriplegia if not treated in a timely manner. Because the primary pathology of this disease is caused by compression, thus generating spinal cord ischemia, we believed there must be a correlation between the degree of compression and the clinical assessment of patients with cervical myelopathy, but we did not find any study in the literature that made this correlation. Because there is doubt the literature we aimed, in our study, to analyze the correlation between the degree of clinical impairment of patients with cervical myelopathy and the Torg index. METHODS: A prospective, descriptive

  18. L2₁ and XA Ordering Competition in Hafnium-Based Full-Heusler Alloys Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb).

    Science.gov (United States)

    Wang, Xiaotian; Cheng, Zhenxiang; Wang, Wenhong

    2017-10-20

    For theoretical designing of full-Heusler based spintroinc materials, people have long believed in the so-called Site Preference Rule (SPR). Very recently, according to the SPR, there are several studies on XA-type Hafnium-based Heusler alloys X₂YZ, i.e., Hf₂VAl, Hf₂CoZ (Z = Ga, In) and Hf₂CrZ (Z = Al, Ga, In). In this work, a series of Hf₂-based Heusler alloys, Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb), were selected as targets to study the site preferences of their atoms by first-principle calculations. It has been found that all of them are likely to exhibit the L2₁-type structure instead of the XA one. Furthermore, we reveal that the high values of spin-polarization of XA-type Hf₂VZ (Z = Al, Ga, In, Tl, Si, Ge, Sn, Pb) alloys have dropped dramatically when they form the L2₁-type structure. Also, we prove that the electronic, magnetic, and physics nature of these alloys are quite different, depending on the L2₁-type or XA-type structures.

  19. Aspectos lineares e espaciais da correlação entre a produtividade de forragem de milho e a porosidade do solo sob plantio direto Linear and spatial aspects of the correlation between the corn forage yield and the soil porosity under no-tillage

    Directory of Open Access Journals (Sweden)

    Ronaldo C. Lima

    2009-03-01

    Full Text Available A porosidade do solo é de extrema importância à produtividade agrícola, uma vez que, em condições adversas, pode dificultar a penetração das raízes e, consequentemente, limitar o adequado aproveitamento dos nutrientes e da água disponível. Na Fazenda Bonança, em Pereira Barreto - SP, em 2005, foi analisada a produtividade de forragem do milho (MSF, a macroporosidade (MA, a microporosidade (MI e a porosidade total (PT de um Latossolo Vermelho distrófico (Acrustox Háplico, sob plantio direto, em três profundidades. O objetivo foi estudar as correlações lineares e espaciais entre os atributos da planta e do solo, na tentativa de selecionar, entre os do solo, um indicador da sua qualidade física de boa representatividade para a produtividade da forragem. Foi instalada a malha geoestatística para a coleta dos dados do solo e da planta, contendo 125 pontos amostrais numa área de 2.500 m². Os atributos estudados apresentaram variabilidade entre baixa e muito alta. Também, seguiram padrões espaciais claramente definidos, com alcances da dependência espacial entre 6,6 e 31,1 m. Apesar da correlação linear simples entre a MSF e a MI na profundidade de 0,10-0,20 m ter sido baixa, foi extremamente significativa. Contudo, do ponto de vista espacial, houve elevada correlação inversa entre tais variáveis. Assim, a MI2 apresentou-se como satisfatório indicador da qualidade física do solo de Pereira Barreto - SP, quando destinado à produtividade de forragem do milho.Soil porosity is of great importance for the crop yield, as the unfavorable conditions can hinder the roots penetration and, therefore, limit the appropriate nutrients and available water uptake. In the year of 2005, on Bonança farm, in Pereira Barreto - SP, Brazil, the corn forage yield (CFY, macroporosity (MA, microporosity (MI and total porosity (TP of a Typic Hapludox soil were analyzed concerning three different depths, under no-tillage. The objective was to

  20. Genetic correlation between traits in the ESALQ-PB1 maize population divergently selected for tassel size and ear height Correlação genética entre caracteres na população de milho ESALQ-PB1 após seleção divergente para tamanho do pendão e altura da espiga

    Directory of Open Access Journals (Sweden)

    Austeclínio Lopes Farias Neto

    2001-03-01

    Full Text Available Full-sib and selfed (S1 progenies were obtained from sub-populations of ESALQ-PB1, divergently selected for tassel size (T+ and T- and ear height (E+ and E-, and used for estimating genetic and phenotypic correlation coefficients between traits. The analyzed traits were: EW- total ear weight (g/plant, PH- plant height (cm, EH- ear height (cm, TB- tassel branch number and TL- tassel length. The highest genetic (rG and phenotypic (rF correlation was observed for the combination PH x EH, as expected, with average of 0.800 and 0.778, respectively over sub-populations and locations. It is apparent that divergent selection for tassel size did not affect greatly the correlation between PH and EH in the full sib progenies, but in the inbred progenies the correlation was smaller in the sub-population selected for larger tassels. Genetic correlation between PH and EH with tassel traits was always positive but ranged from 0.020 to 0.668 in Piracicaba and from 0.06 to 0.309 in Rio Verde. Genetic correlation between PH and EH with yield (EW also was positive in the range of 0.087 to 0.503. EH showed higher correlation with EW in relation to PH x EW and differences were larger in the sub-populations divergently selected for ear height. Correlation between tassel traits with other traits was positive in most of instances and a lack of consistency was observed among sub-populations. Generally the coefficients of genetic and phenotypic correlation differed substantially from the estimates in the base population ESALQ-PB1 before divergent selection for tassel size and ear placement. Divergent selection affected the correlation between traits under unpredicted and varying magnitudes.Progênies de irmãos germanos e de autofecundação (S1 foram obtidas de sub-populações de ESALQ-PB1 após seleção divergente para tamanho do pendão (T+ e T- e altura da espiga (E+ e E- e utilizadas para estimar os coeficientes de correlação genética e fenotípica entre

  1. Hf-Nd Isotopic Correlation in the Deccan Flood Basalt Province

    Science.gov (United States)

    Saha, A.; Basu, A. R.; Barling, J.; Anbar, A. D.; Hooper, P. R.

    2001-12-01

    Hafnium isotopes along with other isotopic and geochemical characteristics, including incompatible trace elements, of several of the lower formations of the Deccan Flood Basalt Province were analyzed to characterize petrogenesis of different tholeiitic lava suites, especially with respect to potential mantle and crustal sources. The rare earth elements of the different formations (from top to bottom- Mahabaleshwar, Ambenali, Bushe, Khandala and Neral) all show an LREE-enriched signature, concentrations varying between 30 to 60 times chondrite for La. (La/Lu)n values range from 4.1 to above 8 with the exception of Ambenali, which has a less LREE-enriched signature with (La/Lu)n values ranging between 3.6 to 5.3. Hafnium isotopic data of the lower formations of the Deccan show initial \\epsilonHf(T) values covering a range from -3 to -28. 176Lu/177Hf varies between 0.20 to 0.70. f(Lu/Hf) varies within a narrow range, between -0.90 to -0.97 while f(Sm/Nd) ranges from -0.84 to -0.86. Bushe gives the lowest range of \\epsilonHf(T) from -21 to -28 with the corresponding \\epsilonNd(T) varying between -4.0 and -16.9, while Khandala for almost the same range of neodymium isotopic values has \\epsilonHf(T) between -11 and -15. The \\epsilonHf(T) values of Neral is in between those of Khandala and Bushe, around -19. Ambenali, has the narrowest range with \\epsilonHf(T) of -3 and \\epsilonNd(T) between 3 and 5. The Ambenali suite reflects the least contaminated of the Deccan suite of lavas as analyzed here and previously confirmed by other isotopic studies. In Hf-Nd isotope correlation plot, the lower Deccan formations of Neral, Khandala and Bushe define individual subparallel arrays that are shallower than the oceanic basalt array and the overall terrestrial array, including the crustal array, although the bulk of the lower formation data fall within the crustal array of Vervoort et al (1999). From these subparallel Hf-Nd arrays, it is evident that the other end

  2. Growth of conductive HfO{sub 2-x} thin films by reactive molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Kleebe, Hans-Joachim [Institut fuer Angewandte Geowissenschaften, TU Darmstadt (Germany)

    2009-07-01

    Thin films of oxygen deficient hafnium oxide were grown on single crystal c-cut and r-cut sapphire substrates by reactive molecular beam epitaxy. The oxidation conditions during growth were varied within a wide range using RF-activated oxygen. Hafnium oxide thin films were characterized using X-ray diffraction, resistivity measurements ({rho}-T) and transmission electron microscopy (TEM). The results show a dramatic increase in conductivity of the deposited oxygen deficient hafnium oxide thin films with decreasing oxidation conditions during growth. The electrical properties of deficient hafnium oxide thin films varied from insulating over semiconducting to conducting. X-ray diffraction data as well as TEM data rule out the possibility of conductivity due to metallic hafnium.

  3. Correlação entre cefaléia e disfunção temporomandibular Correlation between headache and temporomandibular joint dysfunction

    Directory of Open Access Journals (Sweden)

    Mariana Sampaio Menezes

    2008-01-01

    Full Text Available A relação entre disfunções temporomandibulares (DTM e os diferentes tipos de cefaléias ainda não está bem compreendida, mas a dor de cabeça é provavelmente o sintoma mais comum da DTM. O objetivo deste estudo foi correlacionar cefaléia com o índice clínico de Fonseca de avaliação da DTM. Participaram 160 voluntários estudantes da Universidade Nove de Julho na faixa dos 18 aos 36 anos, sendo 80 mulheres e 80 homens. Foram aplicados dois questionários: o índice clínico de Fonseca e um questionário sobre cefaléia. Os dados foram analisados estatisticamente e o nível de significância fixado em pThe relationship between temporomandibular joint disorders (TMD and different kinds of headaches is still not well understood, though headache is probably the most common symptom of TMD. The aim of this study was to correlate headache with Fonseca's TMD clinical index. A total of 160 university students aged 18 to 36 years old were selected, half women, half men. Two questionnaires were applied to them: the Fonseca clinical questionnaire and one on headache. Data were statistically analysed and significance level set at p<0.05. Results showed a higher prevalence of TMD among female individuals with headache, but a direct relationship between headache and degree of temporomandibular joint dysfunction could not be found.

  4. Correlações entre alterações de fala, respiração oral, dentição e oclusão Correlations between speech disorders, mouth breathing, dentition and occlusion

    Directory of Open Access Journals (Sweden)

    Roberta Lopes de Castro Martinelli

    2011-02-01

    Full Text Available OBJETIVO: verificar as correlações entre alterações de fala e sinais de respiração oral ao tipo de dentição e oclusão, utilizando-se registros em vídeo. MÉTODOS: estudo retrospectivo, de 397 pacientes, por meio de levantamento do roteiro de filmagem ROF. Tipos de alterações de fala e de sinais de respiração oral foram avaliados por Fonoaudiólogos Especialistas em Motricidade Orofacial e comparados com os tipos oclusais propostos por Angle e com parâmetros da dentição, ambos avaliados por Ortodontista. Para a análise estatística foi utilizado o programa SPSS (Statistical Package for Social Sciences, em sua versão 13.0. Para a análise de correlação de Spearman, todos os dados da avaliação foram pareados e analisados. Foi adotado o nível de significância de 5%. RESULTADOS: Considerando alterações de fala e dados de dentição e oclusão, observou-se paralelismo entre distorção e mordida cruzada, imprecisão e desvio ósseo de linha média inferior, travamento e sobressaliência, travamento e sobremordida, ceceio anterior e Classe III de Angle, ceceio anterior e mordida aberta, ceceio anterior e mordida cruzada; e ceceio anterior e desvio de linha média inferior. Observou-se ainda correlação de oposição entre travamento e mordida aberta, travamento e desvio ósseo de linha média inferior, ceceio anterior e Classe II-1 de Angle, ceceio anterior e sobressaliência; e ceceio anterior e sobremordida. Considerando os sinais de respiração oral e dados de dentição e oclusão, observou-se sinal de paralelismo entre eversão de lábio inferior e sobressaliência, acúmulo de saliva nas comissuras labiais e mordida cruzada, acúmulo de saliva nas comissuras labiais e falta de espaço intra-oral; e lábios entreabertos no repouso e Classe II-1 de Angle. Olheira e classe II-1 de Angle, eversão de lábio inferior e Classe II-1 de Angle; e lábio superior encurtado e sobremordida apresentaram correlação de oposi

  5. Determinantes de la precarización laboral en Argentina entre 2003-2013: entre los cambios y las continuidades

    Directory of Open Access Journals (Sweden)

    Marcelo Delfini

    2016-03-01

    Full Text Available El crecimiento económico experimentado por Argentina desde 2003 ha tenido su correlato en la mejora de los indicadores laborales. No obstante, la precarización laboral se ha mantenido, luego de una baja importante hasta el año 2007, en valores muy elevados. Partiendo de la idea central que la precarización constituye para el capital, una reducción de costos, el objetivo de este artículo es dar cuenta de los determinantes de la informalidad entre los trabajadores asalariados, estableciendo continuidades y cambios entre los años 2003 y 2013. Para ello utilizamos una metodología cuantitativa con fuentes secundarias de información, a partir de las cuales realizamos dos tipo de análisis, el primero de carácter descriptivo a partir del cual se busca dar cuenta de las características del mercado de trabajo argentino entre 1990 y 2013 y el segundo se realiza por medio de una regresión logística binomial, que permite acercarnos a los determinantes de la precarización de las condiciones de trabajo. En este sentido, se pudo observar que entre los años 2003 y 2013, se consolidó una precarización laboral, cuyos determinantes no lograron modificarse sustancialmente entre los años de referencia.

  6. Correlação entre métodos tradicionais e espectroscopia de ultra-som na determinação de características físico-químicas do leite Correlation between traditional methods and ultrasonic spectroscopy for measurement of milk physical-chemical characteristics

    Directory of Open Access Journals (Sweden)

    E.H.G. Ponsano

    2007-08-01

    Full Text Available Compararam-se a espectroscopia de ultra-som (US e os métodos tradicionais (MT utilizados para a determinação de características físico-químicas do leite e estimaram-se as correlações entre esses métodos e suas acurácias. As características densidade, extrato seco desengordurado (ESD, teor de proteínas e teor de gordura foram determinadas em 65 amostras de leite cru por ambos os métodos. As densidades médias determinadas pelo US e pelos MT não diferiram entre si (P=0,14, e a correlação encontrada entre os dois métodos para a determinação da densidade não foi significativa (P= 0,08. Os teores médios de ESD, proteína e gordura encontrados pelo US e pelos MT foram diferentes (P=0,04, PThe ultrasonic spectroscopy (US and the traditional methods (TM used for the measurement of milk physical-chemical characteristics were studied and the correlations between these methodologies and their accuracies were estimated. Milk density, solids-non-fat (SNF, protein and fat contents were determined in 65 raw milk samples by both methods. Means of density determined by US and TM did not differ (P=0.14, although no significant correlation was found (P=0.08 between the methods used for the determination of this characteristic. Means of SNF, protein and fat contents determined by US and TM differed (P=0.04, P<0.0001 and P<0.0001, respectively. Correlations between both methods used for the analysis of these characteristics were positive and significant (r=0.0109, r=0.0007 and r= <0.0001, respectively, and the accuracies of the methods for these analysis were 0.160, 0.062 and 0.145, respectively. The regression equation of US results on TM for fat content showed a coefficient of determination of 0.5936.

  7. Comparison of HfCl4, HfI4, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO2 films deposited by ALD: A DFT study

    International Nuclear Information System (INIS)

    Cortez-Valadez, M.; Fierro, C.; Farias-Mancilla, J.R.; Vargas-Ortiz, A.; Flores-Acosta, M.; Ramírez-Bon, R.; Enriquez-Carrejo, J.L.

    2016-01-01

    Highlights: • Hafnium oxide growth on Si(100) by atomic layer deposition was simulated. • The interface structure was considered as silicate and silicide. • The interface was studied employing DFT. • TDMA-Hf precursor show better interface stability. - Abstract: The final structure of HfO 2 films grown by atomic layer deposition (ALD) after reaction with OH − ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl 4 (hafnium tetrachloride), HfI 4 (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO–H was studied employing the B3LYP (Becke 3-parameter, Lee–Yang–Parr) hybrid functional and the PBE (Perdew–Burke–Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

  8. Correlation of body mass index Z-scores with glucose and lipid profiles among overweight and obese children and adolescents

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Nogueira-de-Almeida

    2018-05-01

    Full Text Available Objective: To evaluate the prevalence of abnormalities in plasma lipid and glucose profiles among overweight and obese children and adolescents, and to assess the presence of a correlation between body mass index Z-scores and indicators of comorbidities related to both profiles. Methods: This was a multicenter cross-sectional study conducted at two outpatient clinics. The study included all 417 comers for the first visit from 2008 to 2012, aged between 7 and 18 years, with BMI above the Z-score +1. Anthropometry and blood sampling were obtained. The prevalence of dyslipidemias, hyperglycemia, and insulin resistance were evaluated, together with the correlations of these variables with the increase of Z-BMI. Results: Dyslipidemia was observed in 43.4% of the boys and 66.1% of the girls, with no difference between genders. High glucose levels were detected in 6.2% of the individuals. Insulin resistance was present in 32.3% and 41.7% of the cases, with no statistical significance between boys and girls. Correlations between the Z-BMI were noted for triglycerides in the entire group and among girls; for HDL-c, only among girls; for glucose, a correlation was observed for the entire group, but not when stratified by gender. The indicators of insulin resistance were all correlated with Z-BMI, even when corrected for age. Conclusions: Overweight and obesity give origin to a high prevalence of dyslipidemia and insulin resistance. BMI Z-scores showed a weak positive correlation with glucose and triglyceride, and negative with HDL-c. In turn, the strongest positive correlation was found with insulin resistance indicators. Resumo: Objetivo: Avaliar a prevalência de anormalidades nos perfis lipídico e glicêmico entre crianças e adolescentes com sobrepeso e obesidade e também verificar se existe correlação entre os escores-z de índice de massa corporal (z-IMC e indicadores de comorbidades ligados a esses perfis. Métodos: Estudo de corte transversal

  9. Synthesis and characterization of hafnium carbide microcrystal chains with a carbon-rich shell via CVD

    International Nuclear Information System (INIS)

    Tian, Song; Li, Hejun; Zhang, Yulei; Liu, Sen; Fu, Yangxi; Li, Yixian; Qiang, Xinfa

    2013-01-01

    Graphical abstract: Novel HfC microcrystal chains have been synthesized via a catalyst-assisted chemical vapor deposition process. SEM results show the chains have a periodically changing diameter and a nanoscale sharpening tip. Analysis of TEM/SAED/EELS/EDX data shows the single-crystal chains grow along a [0 0 1] direction and consist of a HfC core and a thin carbon-rich shell with embedded HfC nanocrystallites surrounding the core. This work achieves the controllable preparation of nanoscale HfC sharpening tips for application as a point electron emission source and facilitates the application of HfC ultrafast laser-triggered tips in attosecond science. Highlights: •HfC microcrystal chains were synthesized by a catalyst-assisted CVD. •The chains grow along a [0 0 1] direction and have a periodically changing diameter. •Single-crystal HfC core is sheathed by a thin carbon-rich shell. •A growth mechanism model is proposed to explain the growth of microcrystal chians. •This work achieves the controllable preparation of nanoscale HfC sharpening tips. -- Abstract: Novel hafnium carbide (HfC) microcrystal chains, with a periodically changing diameter and a nanoscale sharpening tip at the chain end, have been synthesized via a catalyst-assisted chemical vapor deposition (CVD) process. The as-synthesized chains with many octahedral microcrystals have diameters of between several hundreds of nm and 6 μm and lengths of ∼500 μm. TEM diffraction studies show that the chains are single-crystalline HfC and preferentially grow along a [0 0 1] crystal orientation. TEM/EELS/EDX analysis proves the chains are composed of a HfC core and a thin (several tens of nm to 100 nm) carbon-rich shell with the embedded HfC nanocrystallites (typically below 10 nm) surrounding the core. The growth mechanism model for the chains based on the vapor–liquid–solid process, the vapor–solid process, and the HfC crystal growth characteristics is discussed

  10. Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of N'-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide.

    Science.gov (United States)

    Emam, Sanaa M; El-Saied, Fathy A; Abou El-Enein, Saeyda A; El-Shater, Heba A

    2009-03-01

    Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of furan-2-carbaldehyde 4-methoxy-N-anilinoacetohydrazone were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment and molar conductivity. Mononuclear complexes are obtained with 1:1 molar ratio except complexes 3 and 9 which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a neutral bidentate one and coordination occurs via the carbonyl oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the enolic oxygen atom, azomethine nitrogen atom and the oxygen atom of furan ring. Moreover, the ligand behaves as a neutral tridentate and coordination occurs via the carbonyl oxygen, azomethine nitrogen and furan oxygen atoms as well as a monobasic bidentate and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complex 10 possesses a square planar geometry. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes.

  11. Comparison of HfCl4, HfI4, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO2 films deposited by ALD: A DFT study

    Science.gov (United States)

    Cortez-Valadez, M.; Fierro, C.; Farias-Mancilla, J. R.; Vargas-Ortiz, A.; Flores-Acosta, M.; Ramírez-Bon, R.; Enriquez-Carrejo, J. L.; Soubervielle-Montalvo, C.; Mani-Gonzalez, P. G.

    2016-06-01

    The final structure of HfO2 films grown by atomic layer deposition (ALD) after reaction with OH- ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl4 (hafnium tetrachloride), HfI4 (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO-H was studied employing the B3LYP (Becke 3-parameter, Lee-Yang-Parr) hybrid functional and the PBE (Perdew-Burke-Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

  12. El periodista, entre el Poder

    Directory of Open Access Journals (Sweden)

    JL Dader

    2014-10-01

    Full Text Available El periodismo se debate, desde sus orígenes, entre la reproducción servil de versiones interesadas o la distorsión de propio cuño, por conocimiento insuficiente de una realidad que sólo puede entrever. Los poderes que amenazan la independencia periodística no han hecho más que crecer o aumentar su habilidad con el paso del tiempo. Surgido como ‘oficio de esclavos’ en la época romana, muchos indicadores actuales parecen retornarle al punto de partida: relaciones públicas estratégicas a gran escala, auge de los ‘spin doctors’, extorsión descarnada en las democracias más débiles y populismo de las redes sociales, entre otros. Todo ello, unido o alentado por la degradación interna y el desaliento de la propia institución periodística incapaz de distanciarse de todas esas fuerzas. Su respuesta no puede ser de alianza o competencia con los poderes que la circundan, sino de hábil distanciamiento para moverse entre todos ellos sin dejar de ejercer la vigilancia que los ciudadanos siguen necesitando de su ejercicio profesional.

  13. Electron-gamma directional correlations; Correlations directionnelles electron-gamma

    Energy Technology Data Exchange (ETDEWEB)

    Gerholm, T R [Commissariat a l' Energie Atomique, Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)

    1966-10-01

    of internal conversion process containing the dynamic effects appears to be coherent and well understood. The penetration matrix effects can then be used as independent and complementary sources of information for the study of problems on nuclear structure. (author) [French] Dans le premier chapitre, l'auteur demontre l'interet des correlations angulaires electrons de conversion-gamma en spectrometric nucleaire et souligne la presence ''d'elements de matrice de penetration'' et l'importance de corrections ''dynamiques'', causees par la dimension finie du noyau. Dans le chapitre 2, l'auteur expose les methodes experimentales pour l'etude de la correlation electron-gamma. Une etude comparative est faite entre la correlation angulaire electron de conversion-gamma et la correlation angulaire gamma-gamma. Il est demontre qu'une mesure simultanee de ces deux fonctions de correlation permet d'eliminer les facteurs d'attenuations dus a l'action des champs extranucleaires. Une etude complete de ces champs est menee dans le chapitre 3 avec, principalement, la mise en evidence des effets ''de trou'' correspondant a une interaction de structure hyperfine entre le spin du noyau et celui de son atome. Pour une periode du niveau intermediaire de l'ordre de la nanoseconde, les attenuations creees par la formation de trou ne peuvent pas etre negligees, chaque fois que les atomes radioactifs sont inclus dans un milieu isolant. Les experiences permettant la determination des coefficients b{sub 2}(E{sub 2}) et {alpha}{sub K}(E{sub 2}) du {sup 198}Hg sont decrits chapitre 4. Dans le chapitre 5, l'auteur applique la determination des elements de matrice de penetration dans le processus de conversion M{sub 1} a l'etude des problemes sur la structure nucleaire. Dans le chapitre 6 sont decrites des experiences mettant en evidence le mode de transition E{sub 0} en competition directe avec la conversion interne M{sub 1} et E{sub 2}. (auteur)

  14. A spanish mineral of zirconium and hafnium. Separation of the two elements by liquid-liquid extraction, using tributyl phosphate as chelating agent; Beneficio de un mineral espanol de circonio-hafnio. Separacion de ambos elementos por extraccion liquido-liquido, empleando fosfato de tributilo como agente de quelacion

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Sanchez, F; Cruz Castillo, F. de la; Fernandez Cellini, R

    1962-07-01

    The zirconium and Hafnium oxides are obtained from a Spanish mineral of zircon with an average contest of 55% in ZrO{sub 2}-HfO{sub 2}. An alkaline fusion to open the mineral, followed by a purification by crystallization as (Zr O-Hf O)Cl{sub 2} H{sub 2}O or as (Zr-Hf) (SO{sub 4}){sub 2}. 4H{sub 2}O, is used. A discussion of the best experimental conditions for opening the mineral and of the purification method is made. (Author) 45 refs.

  15. 6-Peroxo-6-zirconium crown and its hafnium analogue embedded in a triangular polyanion: [M6(O2)6(OH)6(gamma-SiW10O36)3]18- (M = Zr, Hf).

    Science.gov (United States)

    Bassil, Bassem S; Mal, Sib Sankar; Dickman, Michael H; Kortz, Ulrich; Oelrich, Holger; Walder, Lorenz

    2008-05-28

    We have synthesized and structurally characterized the unprecedented peroxo-zirconium(IV) containing [Zr6(O2)6(OH)6(gamma-SiW10O36)3]18- (1). Polyanion 1 comprises a cyclic 6-peroxo-6-zirconium core stabilized by three decatungstosilicate units. We have also prepared the isostructural hafnium(IV) analogue [Hf6(O2)6(OH)6(gamma-SiW10O36)3]18- (2). We investigated the acid/base and redox properties of 1 by UV-vis spectroscopy and electrochemistry studies. Polyanion 1 represents the first structurally characterized Zr-peroxo POM with side-on, bridging peroxo units. The simple, one-pot synthesis of 1 and 2 involving dropwise addition of aqueous hydrogen peroxide could represent a general procedure for incorporating peroxo groups into a large variety of transition metal and lanthanide containing POMs.

  16. Correlação entre a resposta do algodoeiro à adubação e a porcentagem de saturação em bases em vários tipos de solos do Estado de São Paulo Correlation between cotton responses to fertilizers and percentage of base saturation in soils

    Directory of Open Access Journals (Sweden)

    Milton Geraldo Fuzatto

    1966-01-01

    Full Text Available É discutido um aspecto da relação entre o efeito da adubação no algodoeiro e a análise química do solo, nas condições do Estado de São Paulo. Correlação entre a resposta à adubação e a porcentagem de saturação em bases no solo, foi verificada no estudo de 126 experimentos, conduzidos em vários tipos de solo. Uma equação polinomial de 2.° grau, descreve a correlação obtida, com um coeficiente R = 0,676xx.In this paper, the correlation between cotton responses to fertilization, and percentage of base saturation in soils, in the State of São Paulo, is discussed. A second degree polynomial, based on data collected from 126 experiments, was found to fit the data satisfactorily, with a correlation coefficient R = 0.676xx. The results indicate the possibility of estimating the effects due to fertilization in cotton crops, by use of the mentioned chemical characteristic of soils.

  17. Correlação entre práticas educativas, depressão, estresse e habilidades sociais A correlation between educative practices, depression, stress and social abilities

    Directory of Open Access Journals (Sweden)

    Paula Inez Cunha Gomide

    2005-12-01

    Full Text Available O modelo de Estilo Parental de Gomide é composto por sete práticas educativas, sendo cinco relacionadas ao desenvolvimento de comportamentos anti-sociais (o abuso físico, a punição inconsistente, a disciplina relaxada, a monitoria negativa e a negligência e duas favoráveis ao desenvolvimento de comportamentos pró-sociais (a monitoria positiva e o comportamento moral. O Inventário de Estilos Parentais de Gomide - IEP fornece um índice final, que reflete a força das sete variáveis no modo de educar dos pais. O objetivo deste trabalho foi correlacionar o IEP com inventários de depressão, estresse e habilidades sociais. Participaram desta pesquisa oito casais e seus filhos, sendo metade das famílias identificadas como de risco e a outra metade como de não-risco por meio do IEP. Obteve-se pelo teste não-paramétrico de Mann-Whitney correlação positiva entre o IEP e o fator 2 (auto-afirmação na expressão de sentimentos positivos do Inventário de Habilidades Sociais de Del Prette e Del Prette (U=8 e p=0,01, e correlação negativa entre o IEP e Inventário de Stress de Lipp (U=7; p=0,005 e de Depressão de Beck (U=6,5 e p=0,007. A literatura aponta que famílias de risco têm práticas parentais negativas, estresse e depressão elevados e habilidades sociais rebaixadas. Os dados encontrados indicam que o IEP é um instrumento que tem indicadores de comportamento de risco e de não-risco que está em consonância com os outros instrumentos utilizados pela literatura pesquisada.Gomide's Parental Style Model is made up of seven educative practices, five of them related to antisocial behavior development (negligence, inconsistent punishment, careless discipline, negative monitoring and physical abuse; and two of them related to prosocial behaviors (moral modeling and positive monitoring. The Parental Style Inventory (IEP indicates a final index which reflects the influence of each variable on the way parents educate their children

  18. Correlação entre a necrose de frutos associada ao Colletotrichum spp. com as características frutos por nó e produtividade entre genótipos de café arábica Correlation between fruit necrosis associated to Colletotrichum spp. with the fruits per node and yield traits of arabic coffee

    Directory of Open Access Journals (Sweden)

    Gustavo Hiroshi Sera

    2008-02-01

    Full Text Available O fungo Colletotrichum spp. vem sendo associado à graves perdas para a cafeicultura brasileira. Objetivou-se neste trabalho verificar a existência de relação entre a variável necrose de frutos associada ao Colletotrichum spp. ("COL" com a quantidade média de frutos por nó produtivo ("FN" e com a produção ("PRD" em genótipos de café arábica. O ensaio de campo foi realizado no IAPAR (Londrina, PR, Brasil em dezembro de 2004 e em cafeeiros com três anos de idade. A variável "COL" foi avaliada atribuindo-se notas de 1 a 5, onde 1 representam plantas com 0 % a 5 % de frutos necrosados. "FN" foi avaliada seguindo uma escala de notas de 1 a 5, onde 1 representa plantas com 0 a 3 frutos/ nó e nota 5 com mais do que 15 frutos/ nó. A avaliação visual subjetiva da produção foi estimada em litros de frutos em estádio cereja, por planta. A correlação de Pearson foi estimada para avaliar a existência de associações entre as variáveis. Foram observadas correlações positivas e significativas a 1 % entre "COL" e "FN" e entre "COL" e "PRD". A necrose de frutos foi mais intensa em cafeeiros com mais produção e com mais frutos por nó produtivo. Sugere-se que a avaliação da resistência de campo à necrose dos frutos associada à presença de Colletotrichum spp. seja realizada em cafeeiros com alta produção e com alta quantidade de frutos por nó produtivo.Different fungi species of genus Colletotrichum has been associated with losses to the Brazilian coffee crop. The aim of this research was to evaluate the association between the variable fruit necrosis associated to Colletotrichum spp. ("COL" with the fruits per productive node average ("FN" and between "COL" and the yield ("PRD" in Coffea arabica L. genotypes. The field assay was evaluated at IAPAR (Londrina, PR, Brazil, in December 2004 and on coffee trees with three years old. The "COL" variable was evaluated attributing scores from 1 to 5, where score 1 represents plants

  19. Correlação entre padrão facial e relação sagital entre os arcos dentários no estágio de dentadura decídua: considerações epidemiológicas Correlation between facial pattern and sagittal relationship between dental arches in deciduous dentition: epidemiological considerations

    Directory of Open Access Journals (Sweden)

    Omar Gabriel da Silva Filho

    2008-02-01

    Full Text Available OBJETIVO: A inter-relação oclusão e morfologia facial é fundamental para o diagnóstico e planejamento em ortodontia, bem como para determinação do prognóstico de tratamento. De um modo geral, a relação sagital entre os arcos dentários (Classe tende a refletir o comportamento sagital do esqueleto facial (Padrão. O presente trabalho avalia a correlação entre as características morfológicas sagitais da face (Padrão e da oclusão (Classe no estágio de dentadura decídua. METODOLOGIA: A amostra foi composta por 2009 crianças, entre 03 e 06 anos de idade, no período de dentadura decídua completa, de 20 pré-escolas do Município de Bauru - SP. Os resultados demonstraram uma correlação estreita entre o Padrão facial e a Classe. No Padrão I predominou a Classe I (62,99%, seguida pela Classe II (35,82% e Classe III (1,18%. No Padrão II, a Classe II foi predominante (81,35% acompanhada de uma incidência baixa de Classe I (18,64%. No Padrão III, a Classe III estava presente em 50% das crianças, seguida pela Classe I, em 48,64%, e Classe II, em 1,35%. RESULTADOS: A expectativa se comprovou. Há uma tendência da Classe acompanhar o Padrão, desde o estágio de dentadura decídua. Isso foi mais explícito no Padrão II. Os resultados também esclarecem que a oclusão guarda alguma independência em relação ao Padrão. CONCLUSÃO: A maior heterogeneidade na distribuição das Classes ficou para os Padrões I e III. No Padrão II, as Classes se comportaram de forma mais homogênea, com mais de 80% das crianças exibindo Classe II.The interrelationship between occlusion and facial morphology is fundamental for diagnosis and planning in Orthodontics. In general, the sagittal relationship between dental arches (Class tends to reflect the sagittal position of facial skeleton (Pattern. This current paper assesses the correlation between sagittal facial morphological characteristics (Pattern and occlusion (Class in deciduous dentition

  20. Correlación y conversión entre los valores de actividad de la colinesterasa plasmática medida por tres técnicas diferentes Correlation and conversion of plasma cholinesterase activity values using three techniques

    Directory of Open Access Journals (Sweden)

    Jaime Carmona-Fonseca

    2007-07-01

    Full Text Available OBJETIVO: Determinar las relaciones matemáticas entre tres técnicas cuantitativas empleadas para medir la actividad de la colinesterasa plasmática, a partir de los valores de referencia ya establecidos para dos poblaciones de Antioquia, Colombia. MÉTODOS:Diseño descriptivo, transversal y prospectivo. Se conformaron dos muestras independientes representativas de la población laboral adulta (18-65 años, no expuesta a plaguicidas inhibidores de la colinesterasa y vinculada al Seguro Social, del valle de Aburrá (415 personas y del cercano oriente antioqueño (412 personas, del departamento de Antioquia, Colombia. La colinesterasa plasmática (EC 3.1.1.8 se midió mediante tres técnicas cuantitativas: Michel, EQM® y Monotest®. Se elaboraron ecuaciones de regresión que relacionaran entre sí los resultados de las tres técnicas estudiadas. RESULTADOS: Se definieron seis ecuaciones de regresión lineal simple que permitieron relacionar los resultados de las tres técnicas de medición de colinesterasa plasmática analizadas. La correlación entre las técnicas fue moderada (r: de 0,686 a 0,771, pero aumentó (r: de 0,744 a 0,811 al eliminar 12 (1,5% valores extremos. Las asociaciones entre las técnicas fueron altamente significativas (P OBJECTIVES: To determine mathematical correlations of three quantitative techniques to measure plasma cholinesterase, using reference values already established for two populations in the department of Antioquia, Colombia. METHODS: In this descriptive, cross-sectional, prospective study, two independent, representative samples of working adults (18 to 65 years old were examined. In both samples the adults worked for businesses associated with Colombia’s Social Security system. Adults in the two samples had not been exposed to cholinesterase-inhibiting pesticides. The samples were from two neighboring regions of the department of Antioquia: one sample (415 adults was from the Aburrá Valley, and the other

  1. Comparison of HfCl{sub 4}, HfI{sub 4}, TEMA-Hf, and TDMA-Hf as precursors in early growing stages of HfO{sub 2} films deposited by ALD: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Cortez-Valadez, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190 Hermosillo, Son. (Mexico); Fierro, C.; Farias-Mancilla, J.R. [Instituto de Ingeniería y Tecnología, Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez, Av. del Charro 450, Cd. Juárez C.P. 32310, Chihuahua (Mexico); Vargas-Ortiz, A. [Universidad Autónoma de Sinaloa, Facultad de Ingeniería Mochis, Ciudad Universitaria, C.P. 81223 Los Mochis, Sinaloa (Mexico); Flores-Acosta, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190 Hermosillo, Son. (Mexico); Ramírez-Bon, R. [Centro de Investigación y Estudios Avanzados del IPN, Unidad Querétaro, Apdo. Postal 1-798, 76001 Querétaro, Qro. (Mexico); Enriquez-Carrejo, J.L. [Instituto de Ingeniería y Tecnología, Departamento de Física y Matemáticas, Universidad Autónoma de Ciudad Juárez, Av. del Charro 450, Cd. Juárez C.P. 32310, Chihuahua (Mexico); and others

    2016-06-15

    Highlights: • Hafnium oxide growth on Si(100) by atomic layer deposition was simulated. • The interface structure was considered as silicate and silicide. • The interface was studied employing DFT. • TDMA-Hf precursor show better interface stability. - Abstract: The final structure of HfO{sub 2} films grown by atomic layer deposition (ALD) after reaction with OH{sup −} ions has been analyzed by DFT (density functional theory). The interaction of the precursors: HfCl{sub 4} (hafnium tetrachloride), HfI{sub 4} (hafnium tetraiodide), TEMA-Hf (tetrakis-ethylmethylamino hafnium), and TDMA-Hf (tetrakis-dimethylamino hafnium) with HO–H was studied employing the B3LYP (Becke 3-parameter, Lee–Yang–Parr) hybrid functional and the PBE (Perdew–Burke–Ernzerhof) generalized gradient functional. The structural evolution at the Si(100) surface has been analyzed by LDA (local density approximation). The structural parameters: bond length and bond angle, and the vibrational parameters for the optimized structures are also reported. The presence of hafnium silicate at the interface was detected. The infrared spectra and structural parameters obtained in this work agree with previously reported experimental results.

  2. Bases del intercambio entre las sociedades norperuanas y surecuatorianas: una zona de transición entre 1500 A.C. y 600 D.C

    Directory of Open Access Journals (Sweden)

    1993-01-01

    Full Text Available BASES DE L'ECHANGE ENTRE LES SOCIETES NORD-PERUVIENNES ET SUD-EQUATORIENNES : UNE ZONE DE TRANSITION ENTRE 1500 AV. J.C. ET 600 AP. J.C. Cet article est le fruit d’une tentative de coopération entre des chercheurs qui travaillent en Équateur et au Pérou, pour relier les deux aires culturelles nettement différenciées, nord-andine et centre-andine, à partir de la définition et de l’étude d’une zone de transition, localisée entre le Río Jubones dans le sud de l'Équateur et le Río Olmos dans le nord du Pérou, entre environ 1500 av. J.C. et 600 ap. J.C. El artículo es resultado de un intento de cooperación entre investigadores que trabajan el Ecuador y el Perú para vincular las dos áreas culturales marcadamente diferenciadas, norandina y centroandina, a partir de la definición y estudio de una zona de transición, localizada entre el río Jubones, al sur de Ecuador y el Río Olmos, al norte de Perú, entre aproximadamente 1500 AC y 600 DC. BASIS OF THE EXCHANGE BETWEEN NORTH PERUVIAN AND SOUTH ECUATORIAN SOCIETIES: A TRANSITIONAL ZONE BETWEEN 1500 B.C. AND 600 A.C. This paper is a collaborative effort by researchers working in Ecuador and Peru, to explore the relationship between two clearly differentiated cultural areas (North and Central Andes on the basis of a definition and study of the prehistory transitional zone located between Río Jubones in Southern Ecuador and Río Olmos in Northern Peru between 1500 B.C. and 600 A.C.

  3. Relationship among social support, treatment adherence and metabolic control of diabetes mellitus patients Relación entre apoyo social, adhesión al tratamiento y control metabólico de personas con Diabetes Mellitus Relação entre apoio social, adesão aos tratamentos e controle metabólico de pessoas com diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Lilian Cristiane Gomes-Villas Boas

    2012-02-01

    Full Text Available This cross-sectional and quantitative study aimed to analyze the relationship among social support, adherence to non-pharmacological (diet and physical exercise and pharmacological treatments (insulin and/or oral anti-diabetic medication and clinical and metabolic control of 162 type 2 diabetes mellitus patients. Data were collected through instruments validated for Brazil. Social support was directly correlated with treatment adherence. Adherence to non-pharmacological treatment was inversely correlated with body mass index, and medication adherence was inversely correlated with diastolic blood pressure. There were no associations between social support and clinical and metabolic control variables. Findings indicate that social support can be useful to achieve treatment adherence. Studies with other designs should be developed to broaden the analysis of relations between social support and other variables.El presente estudio objetivó analizar la relación entre apoyo social, adhesión a los tratamientos no medicamentoso (dieta y ejercicio físico y medicamentoso(insulina y/o antidiabéticos orales y control clínico-metabólico de 162 personas con diabetes mellitus tipo 2. Se trata de un estudio seccional, de abordaje cuantitativo. Los datos fueron recolectados por medio de instrumentos validados. El apoyo social tuvo correlación directa con la adhesión al tratamiento. Se observó correlación inversa entre adhesión al tratamiento no medicamentoso y índice de masa corporal, así como entre adhesión medicamentosa y presión arterial diastólica. No hubo asociaciones entre apoyo social y variables de control clínico-metabólico. Se concluye que el apoyo social podrá ser útil para obtener la adhesión a los tratamientos. Estudios con otros delineamientos deben ser desarrollados, a fin de ampliar el análisis de las relaciones entre apoyo social y otras variables.O presente estudo objetivou analisar a relação entre apoio social, ades

  4. Correlação linear e espacial entre produtividade de milho (Zea mays L. e atributos físicos de um Latossolo Vermelho distroférrico sob plantio direto do Cerrado Brasileiro = Linear and spatial correlation between corn grains productivity (Zea mays L. and physical attributes in a Haplic Acrustox under no-tillage in the Brazilian Savannah

    Directory of Open Access Journals (Sweden)

    Marcio Lustosa Santos

    2006-07-01

    Full Text Available A produtividade vegetal depende de vários fatores, dentre eles a densidade e a porosidade do solo. No ano agrícola 2004/2005, na Fazenda Experimental de Ensino e Pesquisa da Faculdade de Engenharia (Unesp, Campus de Ilha Solteira, Estado de São Paulo (22º23’’ latitude S; 51º27’’ longitude W, foram analisados a produtividade de grãos de milho (PG, irrigado com pivô central, as densidades da partícula (DP e do solo (DS e a porosidade total (PT de um Latossolo Vermelho Distroférrico, sob plantio direto. O objetivo foi estudar as correlações lineares e espaciais entre os atributos. Foi instalada uma rede geoestatística, para a coleta dos dados do solo e da planta, contendo 120 pontos amostrais, numa área de 0,8 ha. Os atributos do solo apresentaram baixa variabilidade de seus dados, sendo média no da planta. A DS e a PT, na camada superficial, e a PG não variaram aleatoriamente. Elas seguiram padrões espaciais bem definidos, com alcances entre 28,6 e 60,6 m. As correlações lineares múltiplas indicaram que a PT1, a PT3 e a DS3 foram atributos significativos, quando correlacionados com a PG. Entre os atributos do solo, as correlações lineares simples variaram elasticamente. Contudo, quando correlacionados com a PG, tais correlações pouco variaram. Ainda que com reservas devido à baixa correlação, com o aumento da DS3 ocorreu uma diminuição da PG. Por outro lado, as correlações espaciais entre os atributos do solo e a PG foram praticamente nulas, sendo, contudo, elevadas quando exclusivamente entre aqueles do solo.Thevegetal productivity depends on several factors, including the bulk density and the soil porosity. The corn grains yield (GY, under no-tillage system and irrigated, and the following soil attributes (particle density-PD, bulk density-BD, and the total porosity-TP, in a Dystroferric Red Latosol (Haplic Acrustox, located at the Experimental Station of the Faculdade de Agronomia (Unesp, in Ilha

  5. Conceito psicológico de otimismo e uso de drogas entre estudantes de enfermagem Concepto psicológico de optimismo y uso de drogas entre estudiantes de enfermería Psychological concept of optimism and drug use among nursing students

    Directory of Open Access Journals (Sweden)

    Marcos Hirata Soares

    2011-01-01

    Kruskal Wallis. RESULTADOS: Se encontraron diferencias estadísticas significativas para el consumo de tabaco y sedantes entre las diferentes series. Hubo correlación negativa débil en el uso de sedantes, y optimismo. El consumo indebido fue encontrado en relación al alcohol, tabaco, marihuana y sedantes. CONCLUSIONES: Deben realizarse nuevos estudios a fin de comprender los motivos del aumento gradual del uso de tabaco en las series, la caída drástica del uso de tabaco y los sedantes en el Curso de Residencia en Enfermería y la correlación entre el uso de sedantes y optimismo, como forma de prevenir los agravios y promover la salud mental en los estudiantes.OBJECTIVE: To describe the consumption of psychoactive substances among undergraduate nursing students and nursing residents, and verify a correlation between psychoactive substances and the perception of optimism. METHODS: This is a quantitative, descriptive, correlational study involving 229 subjects, including 184 undergraduate students and 45 nursing residents, from a public University of Parana, in 2010. The Life Orientation Test and the Screening Test for Alcohol, Tobacco and other Substances were used for the study. Descriptive statistics, Spearman correlation and Kruskal Wallis statistics were used for analysis. RESULTS: We found significant differences for the consumption of tobacco and sedatives within different series. There was weak negative correlation between sedatives and optimism. Misuse was found for alcohol, tobacco, marijuana and sedatives. CONCLUSIONS: Further studies should be conducted to understand the reasons for the gradual increase in tobacco use in the series, the dramatic decline in tobacco use and sedatives in the Residency Program in Nursing and the correlation between use of sedatives and optimism, in order to prevent injuries and promote mental health in students.

  6. Correlação entre o desempenho de jogadores de futebol no teste de sprint de 30m e no teste de salto vertical Correlation between performance of Soccer players in the 30-meter sprint test and in the vertical jump test

    Directory of Open Access Journals (Sweden)

    Daniel Barbosa Coelho

    2011-03-01

    Full Text Available O objetivo do estudo foi determinar o nível de correlação entre o desempenho nos 10m iniciais, dos 20m finais e no tempo total do teste de sprint de 30m, com o do salto vertical com contra-movimento (CMJ entre jogadores de futebol. Participaram do estudo 167 jogadores das categorias profissional (N. 94 e júnior (N. 73. Foram determinadas as velocidades dos jogadores em 10m (V10, 20m (V20 e no total de 30m (V30. A habilidade de salto foi avaliada através do CMJ. Para correlacionar os dados, foi utilizado o coeficiente de correlação de Pearson com nível de significância de pThe aim of the present study was to determine the association between the results in the counter movement jump (CMJ and the results in the first 10 meters, in the final 20 meters and the in the total 30 meters of a 30-meter sprint. One-hundred and sixty seven Soccer players from the professional (N. 93 and under twenty (N. 74 categories, from a Brazilian first division Soccer club participated in the study. The sprint test consisted of a 30-meter run timed at the 10-meter and at the 30-meter marks. The jump capacity was assessed through the CMJ. Pearson's correlation (r was used to determine the association between these variables. The significance level adopted was p<.05. The U-20 players presented faster V10 and slower V20 than the professionals (p<.05. The correlation (r between CMJ and V10, V20 and V30 were .239, .370 and .408, respectively, for the U20 group and .381, .381 and .470, respectively, for the professional group. Evaluating the two categories together the correlation were; r= 0,293, 0,386 and 0,441 to V10, V20 and V30 respectively. The correlation between CMJ and V10 was weak and moderate for V20 and V30. In the professional category the correlation between CMJ and all the other parameters was moderate. It is probable that higher correlation values for CMJ and V10 for the professionals could be attributed to specific training effects.

  7. Evaluación de la motivación académica y la ansiedad escolar y posibles relaciones entre ellas Avaliação da motivação acadêmica e ansiedade escolar e possível relação entre elas Assessment of academic motivation and school anxiety and possible relationship between them

    Directory of Open Access Journals (Sweden)

    Débora Cecilio Fernandes

    2012-12-01

    elucidam a relação existente entre os dois tipos de motivação e a ansiedade escolar.Academic motivation and anxiety in the academic context are both determinant factors in the student's life, from the emotional and achievement points of view. The aim of this study was to assess motivation and school anxiety of students and to carry out correlation and regression analysis between academic motivation and school anxiety. Children obtained low score of anxiety and moderate score of general motivation, above average levels of extrinsic motivation and under mean levels of intrinsic motivation. Correlation analysis indicated that all correlations were significant and that all of them were positive, except the correlation between anxiety and intrinsic motivation and between intrinsic and extrinsic motivation, which were negative. Regression analysis revealed that extrinsic motivation explains a significant part of anxiety. The data elucidates the existent relation between both types of motivation and school anxiety.

  8. Correlação e correspondência topográfica entre espessura da camada de fibras nervosas da retina e campo visual no glaucoma primário de ângulo aberto Correlation and topographic match between nerve fiber layer thickness and visual field in primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Paula Boturão de Almeida

    2001-04-01

    classificados como discretos: SF e SN. Nos olhos classificados como moderados: SF e SI. Nos olhos classificados como graves: MD e SN; MD e EM; MD e S; CPSD e EM. 4- DN t e TD t; DN s e TD ni; DN i e TD ns. 5- Encontramos correspondência positiva (+ em 36 olhos (51,43% dos casos e correspondência negativa (- em 34 olhos (48,57% dos casos. Conclusões: Concluiu-se que houve poucas correlações significantes entre esses dois exames, e que as existentes foram muito fracas. Conclui-se, também, que houve correspondência topográfica, na análise dos setores mais comprometidos, em 51,43% dos casos.Purpose: To determine the relationship between nerve fiber layer thickness detected by scanning laser polarimetry (GDx and visual field function measured by automated conventional white-on-white perimetry. Methods: 82 eyes of 48 open angle glaucoma patients were studied. The following correlations were inves-tigated: 1- Correlation between mean sensitivity of 4 quadrants plus the fixation point, in dBs, and the mean of the nerve fiber layer thickness of the correspondent retina, in micra. 2- Correlation between mean sensitivity of 4 quadrants plus the fixation point, in dBs, and the mean of the nerve fiber layer thickness of the correspondent retina, in micra, in the patients classified according to the amount of visual field loss. 3- Correlation between the global indices of visual field and the numeric indices of GDx. 4- Correlation between the mean of "total deviation" of visual field and the "deviation from normal" of GDx. 5- Topographic match between visual field and retinal nerve fiber layer thickness changes. Statistical analysis was performed using the Spearmann coeficient correlation test. Results: We observed a very poor correlation regarding: 1- total GDx and VF total; superior GDx and nasal inferior VF; inferior GDx and nasal superior VF; nasal GDx and temporal VF; superior GDx and inferior VF; inferior GDx and superior VF. 2- inferior GDx and nasal superior VF (severe eyes

  9. Corrosion resistant surface for vanadium nitride and hafnium nitride layers as function of grain size

    Science.gov (United States)

    Escobar, C. A.; Caicedo, J. C.; Aperador, W.

    2014-01-01

    In this research it was studied vanadium nitride (VN) and hafnium nitride (HfN) film, which were deposited onto silicon (Si (100)) and AISI 4140 steel substrates via r.f. magnetron sputtering technique in Ar/N2 atmosphere with purity at 99.99% for both V and Hf metallic targets. Both films were approximately 1.2±0.1 μm thick. The crystallography structures that were evaluated via X-ray diffraction analysis (XRD) showed preferential orientations in the Bragg planes VN (200) and HfN (111). The chemical compositions for both films were characterized by EDX. Atomic Force Microscopy (AFM) was used to study the morphology; the results reveal grain sizes of 78±2 nm for VN and 58±2 nm for HfN and roughness values of 4.2±0.1 nm for VN and 1.5±0.1 nm for HfN films. The electrochemical performance in VN and HfN films deposited onto steel 4140 were studied by Tafel polarization curves and impedance spectroscopy methods (EIS) under contact with sodium chloride at 3.5 wt% solution, therefore, it was found that the corrosion rate decreased about 95% in VN and 99% for HfN films in relation to uncoated 4140 steel, thus demonstrating, the protecting effect of VN and HfN films under a corrosive environment as function of morphological characteristics (grain size). VN(grain size)=78±2.0 nm, VN(roughness)=4.2±0.1 nm, VN(corrosion rate)=40.87 μmy. HfN(grain size)=58±2.0 nm, HfN(roughness)=1.5±0.1 nm, HfN(corrosion rate)=0.205 μmy. It was possible to analyze that films with larger grain size, can be observed smaller grain boundary thus generating a higher corrosion rate, therefore, in this work it was found that the HfN layer has better corrosion resistance (low corrosion rate) in relation to VN film which presents a larger grain size, indicating that the low grain boundary in (VN films) does not restrict movement of the Cl- ion and in this way the corrosion rate increases dramatically.

  10. Correlação entre o exame clínico, a mamografia e a ultra-sonografia com o exame anatomopatológico na determinação do tamanho tumoral no câncer de mama Correlation between clinical examination, mammography and ultrasonography with histopathological exam in the determination of tumor size in breast cancer

    Directory of Open Access Journals (Sweden)

    Fernanda Monteiro de Paula Siqueira

    2008-03-01

    Full Text Available OBJETIVO: avaliar qual o melhor método entre o exame clínico (EC, a mamografia (MMG e a ultra-sonografia (US na determinação pré-operatória do tamanho tumoral no câncer de mama, tendo como referência o exame anatomopatológico. MÉTODOS: foram incluídas neste estudo 184 pacientes com lesões mamárias detectadas por MMG e US, palpáveis ou não, e que foram submetidas a ressecção cirúrgica do tumor, com diagnóstico histopatológico de câncer de mama. O maior diâmetro tumoral foi avaliado por EC, MMG e US por um mesmo examinador, e a medida obtida por cada método foi correlacionada com o diâmetro máximo obtido pelo exame anatomopatológico. A análise comparativa foi feita por meio do coeficiente de correlação de Pearson (r. RESULTADOS: o coeficiente de correlação de Pearson encontrado entre o exame anatomopatológico e o EC foi 0,8; entre o exame anatomopatológico e a MMG foi 0,7 e entre o exame anatomopatológico e a US foi 0,7 (pPURPOSE: to evaluate which method is the best to determine pre-surgically the size of breast cancer: clinical examination, mammography or ultrasonography, using as a reference the anatomopathological exam. METHODS: this study has included 184 patients with palpable-or-not breast lesions, detected by mammography and ultrasonography, that were submitted to surgical resection of the tumor, with histopathological diagnosis of breast cancer. The same examiner evaluated clinically the largest tumoral diameter, through clinical examination, mammography and ultrasonography, and the measurements obtained by each method were correlated with the maximum diameter obtained by the anatomopathological exam. The comparative analysis has been done by Pearson's correlation coefficient (r. RESULTS: Pearson's correlation coefficient between the anatomopathological and the clinical exams was 0.8; between the anatomopathological exam and the mammography, 0.7; and between anatomopathological exam and ultrasonography 0

  11. USO DE TABACO ENTRE ADOLESCENTES: REVISÃO DE LITERATURA

    OpenAIRE

    Amanda Márcia dos Santos Reinaldo; Camila Cesar Goecking; Jennifer Perucci de Almeida; Yasmin Narciso Goulart

    2010-01-01

    Revisión sistemática de la literatura sobre el uso de tabaco entre adolescentes. La utilización del tabaco entre adolescentes, en general, puede estar asociada al éxito, a la necesidad de aceptación, a cuestiones familiares, entre otros factores que incentivan de cierta forma a su uso. Las políticas de salud para el área trabajan para prevenir y reducir el consumo, alertando en relación al riesgo al que tal población se expone cuando utiliza tabaco. Conocer el perfil de los adolescentes que u...

  12. Relação entre ansiedade, depressão e desesperança entre grupos de idosos Relación entre ansiedad, depresión y desesperanza entre grupos de ancianos Relations between anxiety, depression and hopelessness among elderly groups

    Directory of Open Access Journals (Sweden)

    Katya Luciane de Oliveira

    2006-08-01

    Full Text Available O envelhecimento é uma etapa da vida que permanece pouco conhecida e estudada, se comparada a outras fases do desenvolvimento humano. Nesta pesquisa buscou-se explorar a relação entre ansiedade, depressão e desesperança entre grupos de idosos. Participaram deste estudo 79 idosos provenientes de centro do terceira idade de um posto de retirada de medicamentos e de uma instituição asilar. Utilizou-se um questionário para os dados de caracterização dos idosos, bem como as escalas Beck para mensurar sintomas de ansiedade, depressão e desesperança. Os resultados evidenciaram relação estatisticamente significativa entre ansiedade, depressão e desesperança nos idosos. O grupo de asilares apresentou uma maior incidência de sintomas ansiosos, depressivos e desesperançosos em relação aos outros dois grupos.El envejecimiento es una etapa de la vida que permanece poco conocida o estudiada, al ser comparada a otras fases del desarrollo humano. Esta investigación buscó explorar la relación entre ansiedad, depresión y desesperanza entre grupos de ancianos. Participaron en este estudio 79 adultos mayores provenientes de tres sitios diferentes: un centro de tercera edad, un puesto de retirada de medicinas y un asilo. Un cuestionario para los datos de caracterización de los ancianos fue utilizado, así como las escalas Beck para mensurar síntomas de ansiedad, depresión y desesperanza. Los resultados dejaron en evidencia relación estadísticamente significativa entre dichos síntomas en los adultos mayores. El grupo proveniente del asilo presentó mayor incidencia de manifestaciones en relación con los demás grupos.Aging is a life stage that remains hardly ever studied and, consequently, unknown if compared to other human development phases. This research investigates the relation between anxiety, depression and hopelessness among elderly groups. 79 elderly people, from three different units, such as a 'third-age-center', a center of

  13. Elastic and thermodynamic properties of zirconium- and hafnium ...

    Indian Academy of Sciences (India)

    2018-02-02

    Feb 2, 2018 ... ties. The volume optimization curves (both LDA and GGA) for binary Rh3V, Rh3Zr and Rh3Hf compounds are shown in ... the strength of covalent bonding of the given material. ..... Bulk modulus is correlated with binding energy or cohesive energy of atoms, since it is a measure of average atomic bond.

  14. Measuring quality indicators in the operating room: cleaning and turnover time Mensuración de indicadores de calidad en un centro quirúrgico: tiempo de limpieza e intervalo entre cirugías Mensuração de indicadores de qualidade em centro cirúrgico: tempo de limpeza e intervalo entre cirurgias

    Directory of Open Access Journals (Sweden)

    Marli de Carvalho Jericó

    2011-10-01

    Full Text Available This exploratory-descriptive study was carried out in the Surgical Center Unit of a university hospital aiming to measure time spent with concurrent cleaning performed by the cleaning service and turnover time and also investigated potential associations between cleaning time and the surgery's magnitude and specialty, period of the day and the room's size. The sample consisted of 101 surgeries, computing cleaning time and 60 surgeries, computing turnover time. The Kaplan-Meier method was used to analyze time and Pearson's correlation to study potential correlations. The time spent in concurrent cleaning was 7.1 minutes and turnover time was 35.6 minutes. No association between cleaning time and the other variables was found. These findings can support nurses in the efficient use of resources thereby speeding up the work process in the operating room.Este estudio exploratorio y descriptivo fue conducido en la Unidad de Centro Quirúrgico de un hospital de enseñanza teniendo por objetivos mensurar el tiempo utilizado para limpieza concurrente en sala de operación (por el Servicio de Higiene y Limpieza y el intervalo entre las cirugías; e, investigar las asociaciones entre: tiempo de limpieza, porte de la cirugía, especialidad de la cirugía, período de ocurrencia y tamaño de la sala. El estudio fue constituido de 101 casos de limpieza (estudio de tiempo de limpieza y 60 cirugías (estudio de intervalo entre cirugías. El método de Kaplan-Meier fue utilizado para el análisis del tiempo y la correlación de Pearson para el estudio de las asociaciones. El tiempo promedio de limpieza concurrente de la sala fue de 7,1 minutos y el del intervalo entre cirugías de 35,6 minutos. No fue encontrada correlación entre el tiempo de limpieza y las demás variables. Estos hallazgos instrumentalizan a los enfermeros en el uso eficiente de recursos, agilizando el proceso de trabajo en el Centro Quirúrgico.Este estudo exploratório-descritivo foi

  15. Gastroesophageal reflux - correlation between diagnostic methods; Refluxo gastroesofagico - correlacao entre metodos diagnosticos

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Maria das Gracas de Almeida; Penas, Maria Exposito; Fonseca, Lea Mirian Barbosa [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept. de Radiologia-Medicina Nuclear; Lemme, Eponina Maria O. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina. Dept. de Clinia Medica-Gastroenterologia; Martinho, Maria Jose Ribeiro [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear

    1999-02-01

    A group of 97 individuals with typical symptoms of gastroesophageal reflux disease (GERD) was submitted to gastroesophageal reflux scintigraphy (GES) and compared to the results obtained from endoscopy, histopathology and 24 hours pHmetry. Twenty-four healthy individuals were used as a control group and they have done only the GERS. The results obtained showed that: (a) the difference in the reflux index (RI) for the control group and the sick individuals was statistically significant (p < 0.0001); (b) the correlation between GERS and the other methods showed the following results: sensitivity, 84%; specificity, 95%; positive predictive value, 98%; negative predictive value, 67%; accuracy, 87%. We have concluded that the scintigraphic method should be used to confirm the diagnosis of GERD and also recommended as initial investiative procedure. (author)

  16. Floridablanca entre la modernidad y la posmodernidad

    OpenAIRE

    Senatore, María Ximena

    2007-01-01

    Este artículo se centra en los diálogos entre el pasado y el presente creados en el marco de la modernidad y de la posmodernidad. La arqueología como práctica social puede ser entendida como un diálogo pasado-presente. Floridablanca es una historia, un sitio, una experiencia, una idea, una utopía. Es también un punto de encuentro entre modernidad y posmodernidad. El objetivo de este trabajo es presentar ciertas reflexiones sobre los diálogos pasado-presente que crean, transforman y reproducen...

  17. Technical Note: A simulation study on the feasibility of radiotherapy dose enhancement with calcium tungstate and hafnium oxide nano- and microparticles.

    Science.gov (United States)

    Sherck, Nicholas J; Won, You-Yeon

    2017-12-01

    To assess the radiotherapy dose enhancement (RDE) potential of calcium tungstate (CaWO 4 ) and hafnium oxide (HfO 2 ) nano- and microparticles (NPs). A Monte Carlo simulation study was conducted to gauge their respective RDE potentials relative to that of the broadly studied gold (Au) NP. The study was warranted due to the promising clinical and preclinical studies involving both CaWO 4 and HfO 2 NPs as RDE agents in the treatment of various types of cancers. The study provides a baseline RDE to which future experimental RDE trends can be compared to. All three materials were investigated in silico with the software Penetration and Energy Loss of Positrons and Electrons (PENELOPE 2014) developed by Francesc Salvat and distributed in the United States by the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory. The work utilizes the extensively studied Au NP as the "gold standard" for a baseline. The key metric used in the evaluation of the materials was the local dose enhancement factor (DEF loc ). An additional metric used, termed the relative enhancement ratio (RER), evaluates material performance at the same mass concentrations. The results of the study indicate that Au has the strongest RDE potential using the DEF loc metric. HfO 2 and CaWO 4 both underperformed relative to Au with lower DEF loc of 2-3 × and 4-100 ×, respectively. The computational investigation predicts the RDE performance ranking to be: Au > HfO 2 > CaWO 4 . © 2017 American Association of Physicists in Medicine.

  18. ¿El dinero importa? Relación entre el presupuesto de la biblioteca y la productividad investigadora de la Universitat Politècnica de València

    Directory of Open Access Journals (Sweden)

    Fernández, Sergio

    2013-12-01

    Full Text Available The aim of this paper is to determine whether there is a significant correlation between the library budget allocated to information resources and the scientific output at Universitat Politècnica de València (UPV. This situation was studied from 2001 to 2012, taking into account different variables: budget, collection size, number of research staff, research output, and use of the collection. In addition, full-text citations in the scientific output of the UPV from 2008 to 2011 were analysed to attempt to study the correlation with the budget and the use of the collection. A correlation was not observed between the budget allocated to information resources and scientific output, with the correlation being strong between the budget for electronic resources and scientific output. Finally, it was not possible to determine a causeeffect relationship between the budget and scientific output.El objetivo del artículo es determinar si existe una correlación significativa entre el presupuesto de la biblioteca asignado a recursos de información y la productividad investigadora en la Universitat Politècnica de València (UPV. Se ha estudiado esta situación desde el año 2001 al 2012 teniendo en cuenta diferentes variables: presupuesto, tamaño de la colección, número de Personal Docente Investigador (PDI, producción de la investigación y uso de la colección. Además se ha analizado la disponibilidad de información en el proceso de investigación de los investigadores de la UPV desde el 2008 al 2012 para intentar estudiar su correlación con el presupuesto y el uso de la colección. No se ha observado una correlación entre el presupuesto asignado a recursos de información y la productividad investigadora, pero sí existe una fuerte correlación entre el presupuesto para recursos en formato electrónico y la productividad investigadora. Finalmente no se ha podido determinar una relación de causa-efecto entre el presupuesto y la productividad

  19. Effect of Advanced Plasma Source bias voltage on properties of HfO2 films prepared by plasma ion assisted electron evaporation from metal hafnium

    International Nuclear Information System (INIS)

    Zhu, Meiping; Yi, Kui; Arhilger, Detlef; Qi, Hongji; Shao, Jianda

    2013-01-01

    HfO 2 films, using metal hafnium as starting material, are deposited by plasma-ion assisted electron evaporation with different Advanced Plasma Source (APS) bias voltages. The refractive index and extinction coefficient are calculated, the chemical state and composition, as well as the stress and aging behavior is investigated. Laser induced damage threshold (LIDT) and damage mechanism are also evaluated and discussed. Optical, structural, mechanical and laser induced damage properties of HfO 2 films are found to be sensitive to APS bias voltage. The film stress can be tuned by varying the APS bias voltage. Damage morphologies indicate the LIDT of the HfO 2 films at 1064 nm and 532 nm are dominated by the nodular-defect density in coatings, while the 355 nm LIDT is dominated by the film absorption. HfO 2 films with higher 1064 nm LIDT than samples evaporated from hafnia are achieved with bias voltage of 100 V. - Highlights: • HfO 2 films are evaporated with different Advanced Plasma Source (APS) bias voltages. • Properties of HfO 2 films are sensitive to APS bias voltage. • With a bias voltage of 100 V, HfO 2 coatings without any stress can be achieved. • Higher 1064 nm laser induced damage threshold is achieved at a bias voltage of 100 V

  20. DIVERSIDAD GENÉTICA ENTRE SUBPOBLACIONES RACIALES BOVINAS DE COSTA RICA

    Directory of Open Access Journals (Sweden)

    Marco Martínez

    2015-01-01

    Full Text Available El objetivo del estudio fue cuantificar la diversidad genética entre 16 subpoblaciones raciales bovinas de Costa Rica, con base en 1412 muestras de ADN bovino de todo el país, evaluadas mediante 18 marcadores microsatélites. El número promedio de alelos (Na por locus dentro de raza fue de 10,3, que varían entre 8 (Holstein×Jersey y 13 (Criolla para doble propósito. El número promedio de alelos efectivo (Ne fue de 5,04, con cambios entre 4,18 (Jersey y 5,64 (Bos taurus×Bos indicus. La heterocigosidad observada promedio fue de 0,77, variando entre 0,73 (Jersey y 0,81 (Bos taurus×Bos indicus. La heterocigosidad esperada (He promedio fue de 0,78, que oscilan entre 0,74 (Jersey y Holstein×Jersey y 0,81 (Bos taurus×Bos indicus, Criolla para doble propósito y Cruces para doble propósito. El contenido de información polimórfica (PIC fue de 0,76, con variaciones entre 0,71 (Jersey y Holstein×Jersey y 0,79 (Criollas para doble propósito y Cruces para doble propósito. El FIS promedio fue de 0,02, con oscilaciones entre -0,03 (Holstein×Jersey a 0,04 (Brahman, Criolla para carne y Cruces para leche. La desviación del equilibrio Hardy Weinberg no fue significativa (p>0,05 en la mayoría de los loci para las subpoblaciones raciales. El subgrupo con mayor número de loci en desequilibrio fue Jersey (8 loci, mientras que los subgrupos Bos taurus×Bos indicus, Criolla para leche y Holstein×Jersey presentaron solo 1 locus en desequilibrio. Los índices de fijación FIS (0,02, FIT (0,05 y FST (0,03 indicaron cierta tendencia hacia la homocigosidad. Los dendrogramas mostraron 3 agrupaciones raciales claramente diferenciadas que coinciden con las razas de origen Bos taurus, Bos indicus y sus respectivos cruces. Los resultados del análisis indicaron que el número de microsatélites empleados sí permitió establecer una discriminación clara a nivel de las frecuencias alélicas y en la distribución del tamaño de los alelos entre las

  1. Relación entre el consumo de drogas y maltrato infantil entre estudiantes universitarios de la universidad en Colombia

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    Monica Rosaura Garcia Baquero

    2015-01-01

    Full Text Available Esta investigación examina la relación entre el uso de drogas en estudiantes de una Universidad Pública en Villavicencio, Colombia, y su relación con el maltrato durante la niñez, utilizando como referente teórico la perspectiva bioecológica. Estudio exploratorio retrospectivo, con una muestra de 313 estudiantes de pregrado. El 10.2% de los encuestados refiere haber sido maltratado en la Infancia y la violencia de mayor uso fue la violencia física seguida de la violencia psicológica. El 56.9% de las estudiantes encuestados han consumido sustancias psicoactivas en algún momento de la vida, y su inicio entre los 13 y los 18 años. Se evidencia maltrato en la infancia con manifestaciones de agresiones físicas, al igual que el consumo de sustancias psicoactivas, pero no se observa una relación estadísticamente significativa entre maltrato durante la infancia y el consumo de sustancias psicoactivas en la muestra estudiada.

  2. Correlação entre tontura e disfunções do metabolismo da glicose Correlation between dizziness and impaired glucose metabolism

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    Adriano Santana Fonseca

    2006-06-01

    Full Text Available INTRODUÇÃO: as alterações do metabolismo da glicose são caracterizadas por estados de hipoglicemia e hiperglicemia. OBJETIVO: A proposta deste trabalho é verificar a associação entre as alterações do metabolismo da glicose, por glicemia de jejum e teste de tolerância à glicose e à tontura, avaliada por sua queixa e exames clínicos e subsidiários. MÉTODO: O estudo foi efetivado num grupo de 33 pacientes divididos em 3 subgrupos: pacientes com queixa de tontura, pacientes diabéticos e pacientes assintomáticos. RESULTADOS: O grupo de pacientes com queixa espontânea ou questionada de tontura apresentava alterações no metabolismo da glicose em 65% dos casos. Já entre os pacientes dos 3 grupos sem queixa de tontura, 30% apresentavam alterações do metabolismo da glicose. 40% dos pacientes que apresentaram queixas de tonturas tinham o exame vestibular clínico e a vectoeletronistagmografia alterados, enquanto que entre os assintomáticos 7,5% apresentaram as alterações vestibulares referidas. CONCLUSÃO: A tontura é um bom indicador de alteração do metabolismo da glicose e a alteração do metabolismo da glicose é um bom indicador de alteração do exame vestibular. O estudo do metabolismo da glicose a partir dos níveis glicêmicos é eficaz e tem resultados próximos dos observados nos estudos que mensuram os níveis insulinêmicos.INTRODUCTION: Impaired glucose metabolism is characterized by conditions of hypo and hyperglycemia. AIM: The objective of the present study was to asses whether or not there is a relationship between impaired glucose metabolism and dizziness. In the clinical laboratory settings, patients were examined using vectoelectronystagmography in association with glycemic levels. METHODS: 33 patients were divided in 3 groups: diabetics; patients with dizziness and a control group. RESULTS: 65% of the patients with dizziness showed impaired glucose metabolism. 40% of the patients with dizziness had

  3. Entre Madres: Talleres de Comunicación

    OpenAIRE

    Cardoso Moreno, María Jesús; Aragonés, Lucía Tomás

    2015-01-01

    En el presente artículo se expone el trabajo de investigación cuyo objetivo fue conocer el grado de satisfacción de las madres con un taller de formación denominado "Entremadres". Las 150 mujeres madres que participaron en el taller en la ciudad de Zaragoza, España, se conformaron en un grupo de 7 u 8 madres y estuvo compuesto por seis sesiones de dos horas cada una, entre los años 2008 y 2013. Este taller fue dirigido a madres con hijos de edades comprendidas entre 2 y 16 años. La frecuencia...

  4. Correlações entre protocolos de determinação do limiar anaeróbio e o desempenho aeróbio em nadadores adolescentes Correlations between anaerobic threshold determination protocols and aerobic performance in adolescent swimmers

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    Juliana Melo Altimari

    2007-08-01

    Full Text Available O objetivo do presente estudo foi correlacionar as velocidades de limiar anaeróbio (LAn obtidas a partir de concentrações fixas de lactato (VLAn 4 e VLAn 3,5mM, velocidade de lactato mínimo (VLac min e velocidade crítica (VC determinada a partir de diferentes distâncias e número de coordenadas: VC1 (50/100/200m, VC2 (100/200/400m, VC3 (50/100/200/400m e VC4 (200/400m com o desempenho nos 400m(s em nadadores adolescentes. Fizeram parte da amostra 15 nadadores (10 meninos e cinco meninas = 14,7 ± 0,7 anos; 61,9 ± 8,5kg; 171,1 ± 8,8cm de nível nacional, com experiência entre cinco e sete anos na natação competitiva. Para análise das correlações entre os índices e o desempenho nos 400m(s foi utilizado o coeficiente de correlação de Pearson. O nível de significância adotado foi de p The purpose of this study was to correlate the anaerobic threshold speeds (ATS obtained from fixed lactate blood concentration (ATS 4 e ATS 3.5 mM, lactate minimum speed (Lac minS and the critical speed (CS determined from different distances and number of coordinates: CS1 (50/100/200 m, CS2 (100/200/400 m, CS3 (50/100/200/400 m and CS4 (200/400 m with the performance in 400 meters (s in adolescent swimmers. The sample was constituted by 15 swimmers (10 boys and five girls = 14.7 ± 0.7 years; 61.9 ± 8.5 kg; 171.1 ± 8.8 cm of national level, with five to seven years of experience in competitive swimming. The correlation between the indexes and the performance in 400 m (s was made using Pearson correlation coefficients. Significance was set at p < 0.01. The correlations between ATS 4 mM, ATS 3.5 mM, Lac minS and the performance in 400 m (s were: r = -0.63, r = -0.90 e r = 0.91, respectively (p < 0.01. The correlations between CS1 (50/100/200 m, CS2 (100/200/400 m, CS3 (50/100/200/400 m, CS4 (200/400 m and the performance in 400 m (s were: r = -0.62, r = -0.97, r = -0.98 e r = -0.94, respectively (p < 0.01. We suggest that ATS obtained from fixed

  5. Diálogo entre el islamismo y occidente

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    Ana María MARTÍN GÓMEZ

    2011-05-01

    Full Text Available Este artículo analiza uno de los fenómenos más actuales de nuestras sociedades pluralistas y multiculturales: el encuentro entre la civilización occidental y la islámica. La elaboración de esta nota crítica se ha llevado a cabo tras la lectura de tres libros fundamentales acerca de esta temática: Un paseo por el laberinto. Sobre política y religión en el diálogo entre civilizaciones, de José María García Gómez-Heras, Laicismo, agnosticismo y fundamentalismo de Antonio García-Santesmases, y El islamismo contra el Islam. Las claves para entender el terrorismo yihadista, de Gustavo de Arístegui. A partir de estos tres ensayos, se ha emprendido un estudio filosófico de la situación actual entre el islamismo y Occidente.

  6. Correlação entre o número de parafusos e o percentual de correção no tratamento cirúrgico da escoliose neuromuscular Correlación entre el número de tornillos y el porcentual de corrección en el tratamiento quirúrgico de la escoliosis neuromuscular Correlation between number of screw and curve correction in the treatment of neuromuscular scoliosis

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    Murilo Tavares Daher

    2009-06-01

    preoperatoria, el porcentual de corrección y el valor de la curva postoperatoria en las radiografías pre y postoperatoria inmediata. Se calculó la densidad de tornillos (número de tornillos por pedículo en el área correspondiente a la curva principal y se evaluó su relación con el porcentaje de corrección, por medio del análisis de corrección de Spearman. RESULTADOS: de los 55 pacientes, 28 (51% eran del sexo femenino y 27 (49% del masculino, con promedio de edad de 16.04 años (dp=4.45. La patología de base más común fue la parálisis cerebral. El valor de la escoliosis preoperatoria fue en promedio de 81.96º (dp=25.49 y de la escoliosis residual de 33.82º (dp=19.02, con porcentual de corrección de 60.28% (dp=15.89. Hubo una relación positiva (r=0.266 y estadísticamente significativa entre la densidad de los tornillos y la corrección de la deformidad (p=0.045. CONCLUSIONES: en el tratamiento quirúrgico de las deformidades neuromusculares, hay una relación positiva entre el mayor número de tornillos dentro del área de la curva principal y el porcentual de corrección.OBJECTIVE: to investigate if the number of pedicular screw (screw density within the major curve correlates with the curve correction in the surgical treatment of neuromuscular scoliosis. METHODS: a total of 55 patients with neuromuscular scoliosis that were exclusively submitted to posterior spinal fusion with pedicular screw constructs were retrospectively investigated. Data included major curve measurements assessed on pre and immediate postoperative radiographs, and the percentage of curve correction. The screw density (number of screw within the major curve relative to the number of available implant sites was calculated; its relationship with the percentage of the curve correction was evaluated by the Spearman's rank correlation coefficient. RESULTS: twenty-eight (51% females and 27 (48% males were analyzed, with mean age of 16.04 years (sd=4.45. The commonest base pathology was the

  7. Relações entre os caracteres de maracujazeiro-azedo Relations between variables in passion fruit

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    Alessandro Dal'Col Lúcio

    2013-02-01

    Full Text Available O objetivo foi identificar os caracteres que mais merecem atenção em experimentos com a cultura do maracujá-azedo (Passiflora edulis Sims e verificar suas relações com o caractere dependente principal produção total de frutos. A partir dos dados de quatro experimentos com a cultura do maracujá calculou-se a matriz de correlações entre todos os caracteres e realizou-se o diagnóstico de multicolinearidade. Em seguida foi aplicada a análise de trilha entre os caracteres restantes. Para identificar os caracteres com maior contribuição na variabilidade total existente foi realizada uma análise de componentes principais. Os caracteres peso médio de polpa e número de frutos são os de maior correlação com o peso total de frutos de maracujá. O teor de sólidos solúveis total, o peso médio de frutos, o comprimento e o diâmetro do fruto, a espessura da casca e a percentagem de polpa tem baixa correlação com o peso total de frutos de maracujá.The aim of this research was to indentify the variables which deserve more attention in experiments with passion fruit (Passiflora edulis Sims and verify their relations with the principal dependent variable: total fruit yield. From data of four experiments with passion fruit culture it was calculated the correlation matrix between the variables and performed the diagnosis of multicollinearity, then applied the path analysis between the variables left. To identify the variables with more contribution in the total variability it was performed analysis of main components. The pulp weight and the fruit number have higher correlation with the fruits total weight. The total soluble solids rate, the average weight of fruits, length and fruit diameter, peel thickness and the pulp percentage has lower correlation with the fruit total weight of passion fruit.

  8. Entre propietarios y migrantes: los encuentros y desencuentros entre Colonos y Aguarunas en el alto mayo”

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    Kenneth E. Garces Montes

    2013-10-01

    Full Text Available La dinámica de conflictos entre colonos y nativos en el Alto Mayo, ha dado como producto continuosenfrentamientos entre caseríos de colonos y comunidades nativas colindantes, así como una seriede procesos judiciales por “usurpación de tierras”, en los cuales no se logra una ejecución efectiva dela sentencia a pesar que esta sea favorable a los nativos, debido a la distancia social que existe entrelos operadores estatales y el conflicto real. Por su parte los mecanismos de convivencia entre colonosy nativos se inician mediante el alquiler de tierras, diseñada como una fórmula temporal para quelos colonos se retiren una vez vencido el plazo del alquiler, sin embargo la ampliación de los plazosprovoca que los mismos adquieran vocación de permanencia.Una serie de actores, de primer, segundo y tercer orden interactúan alrededor de las dos dinámicasde relacionamiento mencionadas; tales como las ONGs, el Estado, organizaciones indígenas, einclusive mafias de traficantes de tierras. Ante esta realidad tan compleja conviene hacer el ejerciciode plantear propuestas de adaptabilidad (o subsistencia de las comunidades nativas, en las quese visualice la supervivencia de lo local frente a lo global en lo que a demarcación de tierras de lascomunidades nativas se refiere.

  9. Correlation between seed size, protein and oil contents, and fatty acid composition in soybean genotypes

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    Maestri, Damián M.

    1998-12-01

    Full Text Available Eighteen soybean genotypes (Glycine max (L. Merrill with maturity groups IV, V, VI or VII were grown in 1995/96 at the Estación Experimental Agropecuaria (EEA-INTA of Manfredi and Marcos Juárez, Argentina. The aim of this research was to determine possible associations between seed size, protein and oil contents, and fatty composition. Seed size varied between 13.9-21.0 g/100 seeds. Protein and oil contents ranged from 331 to 448 and from 198 to 267 g kg-1, respectively, and showed no significant correlation with seed size. There were significant correlations between seed size and individual fatty adds: positive with stearic and oleic and negative with linoleic. The results obtained suggest that seed size and its relationship with individual fatty acids must be considered in soybean breeding programs.

    Se analizaron 18 genotipos de soja (Glycine max (L. Merrill con grupos de madurez IV, V, VI o VIl, cultivados en 1995/96 en la Estación Experimental Agropecuaria (EEA-INTA de Manfredi y Marcos Juárez, Argentina. El propósito de la investigación fue determinar posibles asociaciones entre el tamaño del grano, los contenidos de proteínas y aceite y la composición de ácidos grasos del mismo. El tamaño del grano varió entre 13.9-21.0 g/100 granos. Los porcentajes de proteínas y aceite estuvieron comprendidos entre 331-448 y entre 198-267 g kg-1 respectivamente, y no mostraron correlaciones significativas con el tamaño del grano. Se observaron correlaciones significativas entre el tamaño del grano y determinados ácidos grasos: positivas con esteárico y oleico y negativa con linoleico. Las asociaciones encontradas podrían ser de utilidad en programas de mejoramiento de soja.

  10. Correlação entre índice de massa corporal e circunferência da cintura em crianças Correlación entre índice de masa corporal y circunferencia de la cintura en niños Correlation between body mass index and waist circumference in children

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    Marta Maria Coelho Damasceno

    2010-10-01

    Full Text Available OBJETIVO: Estabelecer uma correlação entre a circunferência da cintura e o Índice de Massa Corporal (IMC na determinação do excesso de peso e distribuição de gordura em crianças de escolas públicas de Fortaleza - CE. MÉTODOS: Trata-se de um estudo transversal, realizado em 12 escolas da rede da pública da cidade de Fortaleza- CE. Participaram 727 crianças de ambos os sexos, com idade variando entre 6 a 11 anos. A coleta de dados ocorreu de março a junho de 2008. RESULTADOS: Os resultados do inquérito mostraram que, de acordo com o IMC,11,4% das crianças encontravam-se em sobrepeso, 6,6% eram obesas e 30,9% apresentaram obesidade central. CONCLUSÃO: Nem toda criança obesa apresentava obesidade central, demonstrando que uma só medida antropométrica não é eficaz na determinação do padrão de gordura na infância.OBJETIVO: Establecer una correlación entre la circunferencia de la cintura y el Índice de Masa Corporal (IMC en la determinación del exceso de peso y distribución de grasa en niños de escuelas públicas en Fortaleza - CE. MÉTODOS: Se trata de un estudio transversal, realizado en 12 escuelas de la red pública de la ciudad de Fortaleza- CE. Participaron 727 niños de ambos sexos, con edad que varió de 6 a 11 años. La recolección de datos ocurrió de marzo a junio de 2008. RESULTADOS: Los resultados de la encuesta mostraron que, de acuerdo con el IMC, 11,4% de los niños se encontraban con sobrepeso, 6,6% eran obesos y 30,9% presentaron obesidad central. CONCLUSIÓN: No todos los niños obesos presentaban obesidad central, demostrando que solo una medida antropométrica no es eficaz para determinar el estándar de adiposidad en la infancia.OBJECTIVE: To establish a correlation between waist circumference and Body Mass Index (BMI and to determine overweight and fat distribution in children from public schools in Fortaleza - CE. METHODS: This is a cross-sectional study conducted in 12 public schools in the city

  11. Impedance Characterization of the Capacitive field-Effect pH-Sensor Based on a thin-Layer Hafnium Oxide Formed by Atomic Layer Deposition

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    Michael LEE

    2014-05-01

    Full Text Available As a sensing element, silicon dioxide (SiO2 has been applied within ion-sensitive field effect transistors (ISFET. However, a requirement of increasing pH-sensitivity and stability has observed an increased number of insulating materials that obtain high-k gate being applied as FETs. The increased high-k gate reduces the required metal oxide layer and, thus, the fabrication of thin hafnium oxide (HfO2 layers by atomic layer deposition (ALD has grown with interest in recent years. This metal oxide presents advantageous characteristics that can be beneficial for the advancements within miniaturization of complementary metal oxide semiconductor (CMOS technology. In this article, we describe a process for fabrication of HfO2 based on ALD by applying water (H2O as the oxygen precursor. As a first, electrochemical impedance spectroscopy (EIS measurements were performed with varying pH (2-10 to demonstrate the sensitivity of HfO2 as a potential pH sensing material. The Nyquist plot demonstrates a high clear shift of the polarization resistance (Rp between pH 6-10 (R2 = 0.9986, Y = 3,054X + 12,100. At acidic conditions (between pH 2-10, the Rp change was small due to the unmodified oxide gate (R2 = 0.9655, Y = 2,104X + 4,250. These preliminary results demonstrate the HfO2 substrate functioned within basic to neutral conditions and establishes a great potential for applying HfO2 as a dielectric material for future pH measuring FET sensors.

  12. A silicon doped hafnium oxide ferroelectric p–n–p–n SOI tunneling field–effect transistor with steep subthreshold slope and high switching state current ratio

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    Saeid Marjani

    2016-09-01

    Full Text Available In this paper, a silicon–on–insulator (SOI p–n–p–n tunneling field–effect transistor (TFET with a silicon doped hafnium oxide (Si:HfO2 ferroelectric gate stack is proposed and investigated via 2D device simulation with a calibrated nonlocal band–to–band tunneling model. Utilization of Si:HfO2 instead of conventional perovskite ferroelectrics such as lead zirconium titanate (PbZrTiO3 and strontium bismuth tantalate (SrBi2Ta2O9 provides compatibility to the CMOS process as well as improved device scalability. By using Si:HfO2 ferroelectric gate stack, the applied gate voltage is effectively amplified that causes increased electric field at the tunneling junction and reduced tunneling barrier width. Compared with the conventional p–n–p–n SOI TFET, the on–state current and switching state current ratio are appreciably increased; and the average subthreshold slope (SS is effectively reduced. The simulation results of Si:HfO2 ferroelectric p–n–p–n SOI TFET show significant improvement in transconductance (∼9.8X enhancement at high overdrive voltage and average subthreshold slope (∼35% enhancement over nine decades of drain current at room temperature, indicating that this device is a promising candidate to strengthen the performance of p–n–p–n and conventional TFET for a switching performance.

  13. Nexos estratégicos entre la retórica y la publicidad

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    Luis Gallardo Vera

    2011-06-01

    Full Text Available El presente artículo contribuye a establecer nexos estratégicos entre la retórica y la publicidad. La adopción del prisma estratégico en los estudios retóricos de la publicidad no es común, sin embargo, la relación entre retórica y publicidad a un nivel estratégico es evidente, teniendo presente los estudios que han investigado la simbiosis entre las dos actividades.Del universo compuesto por las investigaciones sobre retórica y publicidad se seleccionó una muestra de las obras susceptibles de responder a la pregunta de cuáles son los nexos estratégicos entre la retórica y la publicidad. Con este criterio se conformó una muestra teóricamente conducida del universo. La hipótesis de partida ha sido que, si existen documentos que indaguen en la relación entre la retórica y la publicidad, es posible construir un documento que muestre de un modo amplio cuáles son los nexos estratégicos entre ambas actividades. Finalmente, se contrastó que, efectivamente, este documento es único al mostrar ampliamente cuáles son los nexos estratégicos existentes entre la retórica y la publicidad.

  14. Relação entre dor e antecedentes de adoecimento físico ocupacional: um estudo entre músicos instrumentistas Relationship between pain and antecedents of occupational illness: a study among musicians

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    Thaís Branquinho Oliveira Fragelli

    2009-01-01

    Full Text Available Este artigo examina possíveis relações entre os sintomas de dor e os antecedentes físicos (carga física e ambiente físico de trabalho e psicossociais (carga cognitiva, carga psíquica, organização do trabalho de tais sintomas em um grupo de músicos instrumentistas. O trabalho constitui uma pesquisa exploratória envolvendo dados quantitativos e qualitativos e busca compreender aspectos relacionados aos fatores antecedentes do adoecimento muscular segundo a percepção dos músicos. A amostra foi composta por 46 músicos do estado de Goiás e do Distrito Federal, com idades entre 14 e 45 anos, que responderam a um questionário desenvolvido para este estudo. A análise quantitativa realizada por meio do coeficiente de correlação ρ de Spearman indicou uma relação entre a dor e a carga física de trabalho percebida pelo respondente. Os resultados da análise qualitativa confirmaram esta relação entre percepção de dor e carga física. Os resultados são discutidos apontando a necessidade de disseminar a idéia de que o músico deve atentar para sinais de desarmonia do próprio corpo.This paper examines possible relationships between the presence of symptoms of pain and their physical antecedents (physical load and physical environment of work and psychosocial antecedents (cognitive load, psychical load, work organization of these symptoms in musicians. It constitutes an exploratory study involving quantitave and qualitative data that aim to understand aspects related to antecedents factors in the muscular infirmity according to musicians' perceptions. The sample was composed by 46 musicians from the State of Goiás and the Federal District in Brazil, aged 14 through 45, which answered a questionnaire developed for the study. The quantitative analysis, done with Spearman ρ correlation, indicated a relationship between pain and physical work load perceived by the respondents. The qualitative analysis confirmed this relationship

  15. Uma análise da correlação entre o EVA® e o MVA® no contexto das empresas brasileiras de capital aberto Correlation between Economic Value Added and Market Value Added for publicly owned Brazilian companies

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    José Odálio dos Santos

    2005-03-01

    Full Text Available Este artigo trata do tema da criação de valor, da forma como é medida pelo EVA® (Valor Econômico Adicionado e pelo MVA® (Valor de Mercado Agregado, duas metodologias desenvolvidas no final dos anos 80 pela empresa americana de consultoria Stern Stewart & Co. O EVA® é definido como a diferença entre o lucro operacional líquido depois de impostos e o custo do capital investido na empresa, enquanto o MVA® é determinado pela diferença entre o valor de mercado da empresa e o capital total nela investido. Um estudo realizado por G. Bennett Stewart III, que idealizou essas metodologias juntamente com o seu sócio Joel M. Stern, encontrou uma forte correlação entre o EVA® e o MVA®. Visando averiguar se tal resultado se aplica também ao caso das empresas brasileiras, os autores deste artigo realizaram uma pesquisa semelhante, baseada numa amostra formada por empresas de capital aberto cujas ações foram negociadas na Bovespa (Bolsa de Valores de São Paulo durante o período de 1996 a 2001.This article deals with value creation as measured by Economic Value Added (EVA® and Market Value (MVA® which are methods developed by an American consultant, Stern Stewart & Co, in the late l980's. Economic Value Added is defined as the difference between net operating profit after taxes and the cost of capital invested in a company, while Market Value Added is the difference between market value and the total capital invested in a company. G. Bennett Stewart III, who conceived this approach together with his partner Joel M. Stern, found a strong correlation between Economic Value Added and Market Value Added. Our research investigated whether this also applies to a sample of publicly owned Brazilian companies traded on the São Paulo Stock Exchange between 1996 and 2001.

  16. Synergistic effect of carbon nanotube as sintering aid and toughening agent in spark plasma sintered molybdenum disilicide-hafnium carbide composite

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Biswajyoti; Asiq Rahman, O.S.; Sribalaji, M [Materials Science and Engineering, Indian Institute of Technology Patna, Bihta Kanpa Road, Bihta, Patna, Bihar 801103 (India); Bakshi, Srinivasa Rao [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Keshri, Anup Kumar, E-mail: anup@iitp.ac.in [Materials Science and Engineering, Indian Institute of Technology Patna, Bihta Kanpa Road, Bihta, Patna, Bihar 801103 (India)

    2016-12-15

    Hafnium carbide (HfC) along with sintering aids was consolidated at a relatively lower temperature i.e. 1600 °C (i.e. T=~0.41 T{sub m}) under a uniaxial load of 50 MPa by spark plasma sintering. Two different sintering aids such as molybdenum disilicide (MoSi{sub 2}) and carbon nanotube (CNT) were added to enhance the densification and lower the extent of grain growth in the sintered pellets. Density of the sintered pellet increased from 96.0±0.8% in HfC +5 wt% MoSi{sub 2} (HM) to 99.0±0.5% with the addition of 2 wt% CNT in HfC+5 wt% MoSi{sub 2} (HMC) at sintering temperature of 1600 °C. Further, the extent of grain growth drastically reduced from 204% in HM to 50% in HMC. Analysis of linear shrinkage during densification revealed that CNT addition increased densification rate and decreased the time required to reach the density of 99.0±0.5% at 1600 °C. Increased densification and lower degree of grain growth could be due to the synergistic effect offered by the CNT, which are as follows: (i) Lubrication effect of CNT, (ii) Lower activation energy for grain boundary diffusion (iii) Reduction in liquid phase sintering temperature and (iv) Grain boundary pinning. Fracture toughness of the sintered HM and HMC composite was obtained using indentation technique. By the addition of 2 wt% CNT in HM, drastic increase of 91% in fracture toughness was seen. This significant improvement in fracture toughness was due to the enhanced densification and relatively lower grain size of HMC. Also crack bridging, crack deflection, crack arrest, CNT and graphene sheet pull-out and swording played major role in toughening of HMC pellet.

  17. Correlação entre Inventário de Depressão de Beck e cortisol urinário em diabéticos tipo 2 Correlación entre el inventario de Depresión de Beck y el cortisol urinario en diabeticos tipo 2 Correlation between urine cortisol and scores on the Beck Depression inventory in patients with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Alexandra Bulgarelli do Nascimento

    2009-01-01

    Full Text Available OBJETIVO: Verificar a correlação entre o cortisol urinário e o Inventário de Depressão de Beck em diabéticos do tipo 2. MÉTODOS: O cortisol urinário foi avaliado em uma amostra composta por 40 pacientes da Liga de Controle de Diabetes da Disciplina de Endocrinologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo e para a avaliação dos sintomas de depressão foi aplicado o Inventário de Depressão de Beck. RESULTADOS: Alta confiabilidade para o Inventário de Depressão de Beck(Alfa de Cronbach=0,920e correlação significativa foi observada entre cortisol urinário e Inventário de Depressão de Beck(Spearman,r=0.523,pOBJETIVO: Verificar la correlación entre el cortisol urinario y el Inventario de Depresión de Beck en diabéticos del tipo 2. MÉTODOS: El cortisol urinario fue evaluado en una muestra compuesta por 40 pacientes de la Liga de Control de Diabetes de la Disciplina de Endocrinología del Hospital de las Clínicas de la Facultad de Medicina de la Universidad de Sao Paulo y para la evaluación de los síntomas de depresión fue aplicado el Inventario de Depresión de Beck. RESULTADOS: Alta confiabilidad para el Inventario de Depresión de Beck(Alfa de Cronbach=0,920 y correlación significativa observada entre el cortisol urinario e Inventario de Depresión de Beck (Spearman,r=0.523,pOBJECTIVE: To determine the relationship between urinary cortisol and scores on the Beck Depression Inventory in type 2 diabetics. METHODS: The sample consisted of 40 patients with type 2 diabetes from the diabetes control league of the discipline of endocrinology of the HCFM-USP. Measures consisted of urinary cortisol and depression symptoms using the Beck Depression Inventory. RESULTS: The Beck Depression Inventory had a Cronbach's alpha of 0.92. There was a statistically significant correlation between urinary cortisol and scores on the Beck Depression Inventory (Spearman r = 0.52, p < .001. CONCLUSIONS: The

  18. Des tubercules pour la mort: analyses préliminaires des relations entre l'ordre naturel et l'ordre culturel dans l'iconographie Mochica

    Directory of Open Access Journals (Sweden)

    1990-01-01

    Full Text Available Le but de cet article est de démontrer que c’est à partir de savantes observations du milieu naturel que les Mochicas ont puisé leur inspiration pour former leur iconographie. Il y aurait donc une corrélation entre les représentations de plantes ou d’animaux et leurs propriétés et comportements naturels. Nous explorons ici les relations entre les représentations de tubercules, d’humains, de certains animaux, et le monde mortuaire. LOS TUBÉRCULOS Y LA MUERTE. Análisis preliminares de las relaciones entre el orden natural y el orden cultural en la iconografía mochica. Se demuestra en este artículo que, para plasmar su iconografía, los Mochicas se inspiraron de sabias observaciones del medio natural. Entonces había un vínculo entre las representaciones de plantas y animales, sus propiedades y comportamientos naturales. Se indica aquí las relaciones entre las representaciones de tubérculos, de humanos, de ciertos animales, y el mundo mortuorio. TUBERS AND DEATH. Preliminary Analysis of the Relations Between the Natural and Cultural Order in Mochica Iconography. The objective of this article is to demonstrate that the Mochicas have designed their iconography system by studying closely their natural environment. Hence, there is a correlation between the natural comportments of the animals or the properties of the plants and their representations in the iconography. We explore the relation between the representations of tubers, human and animals beings, and the mortuary world.

  19. Violencia sexual entre compañeros y violencia en parejas adolescentes

    OpenAIRE

    Ortega Ruiz, Rosario; Ortega Rivera, Francisco Javier; Sánchez Jiménez, Virginia

    2008-01-01

    El presente estudio ha analizado la presencia de violencia sexual entre compañeros y en las parejas adolescentes y jóvenes. Específicamente se han estudiado las diferencias por sexo, edad y estadio de la relación sentimental tanto en violencia sexual entre iguales como en las parejas, en una muestra de 490 adolescentes (55,7% chicos, 44,3% chicas, edad media 16.08 años). Los resultados descriptivos mostraron la misma incidencia de violencia sexual entre iguales y en las pa...

  20. Correlação entre pressão arterial e peso em crianças e adolescentes de uma escola municipal do noroeste paulista Correlación entre presión arterial y peso en niños y adolescentes de una escuela municipal del Estado de São Paulo Correlation between blood pressure and weight in children and teenagers from a municipal school in the northwestern region of São Paulo

    Directory of Open Access Journals (Sweden)

    Márcia Diana Umebayashi Zanoti

    2009-12-01

    coeficiente de correlación indicó una correlación fuerte y positiva entre el peso/índice de masa corporal y la presión arterial. Conclusiones: Los resultados contribuyeron al diagnóstico precoz de los cambios en la presión de la población estudiada y su prevención en individuos obesos y con sobrepeso.To verify the correlation between weight and blood pressure alterations on students from a public basic education school from the interior of São Paulo. Method: Descriptive and correlational study, with quantitative approach. After collected and categorized the weight and blood pressure of 148 students, the data were typed in Excel and analyzed, through descriptive and inferential stats (cross-tabs and Pearson's correlation test, using the program Statistical Package for Social Science 12th version. Results: The prevailing gender was male (63.5% and the average age was 8.4; 36.5% presented altered corporal weight (3.4% low weight, 10.1% overweight and 23% obesity; 4.7% presented bordering levels of blood pressure and 9.5% presented hypertension. The correlation test indicated strong positive correlation between weight/corporal weight and blood pressure. Conclusions: The results contribute to the precocious diagnosis of blood pressure alterations in the researched population as well as to its prevention in obese and overweight individuals.

  1. Arquitectura de comunicación entre frameworks jadesymfony

    OpenAIRE

    RODRÍGUEZ C., PAOLA J.; GÓMEZ R., SANTIAGO

    2009-01-01

    La inclusión del uso de Agentes dentro del campo del desarrollo de software es una de las principales áreas de estudio en la actualidad. Específicamente, el desarrollo de aplicaciones Web que aprovechen las ventajas que ofrece la tecnología de agentes y en especial las distintas propuestas de comunicación entre frameworks son esfuerzos importantes dentro de este campo. En este sentido, este artículo describe una arquitectura de comunicación entre dos de los principales frameworks de desarroll...

  2. Correlação entre variáveis de composição corporal e metabólica em adolescentes do sexo feminino Correlación entre variables de composición corporal y metabólica en adolescentes del sexo femenino Correlation between metabolic and body composition variables in female adolescents

    Directory of Open Access Journals (Sweden)

    Eliane Rodrigues de Faria

    2009-08-01

    Full Text Available FUNDAMENTO: Análise das alterações metabólicas e de composição corporal em adolescentes. OBJETIVO: Estudar a correlação entre níveis séricos de lipídios, glicemia, insulina, homocisteína, HOMA-IR e pressão arterial, entre si e com variáveis corporais. MÉTODOS: Coletaram-se dados referentes a glicemia, colesterol total e frações (LDL, HDL e VLDL, triacilgliceróis, insulina, homocisteína e pressão arterial em 100 adolescentes de 14 a 17 anos de escolas públicas de Viçosa (MG que já haviam apresentado a menarca. A porcentagem de gordura corporal (%GC foi avaliada pela bioimpedância horizontal. RESULTADOS: Em relação ao estado nutricional, 83%, 11% e 6%, respectivamente, apresentaram eutrofia (EU, risco de sobrepeso/sobrepeso (RS/SP e baixo peso (BP (CDC/NCHS, 2000, e 61% apresentaram alta %GC. O colesterol total foi o que apresentou maior porcentagem de inadequação (57%, seguido do HDL (50%, LDL (47% e triacilgliceróis (22%. Observou-se inadequação em 11%, 9%, 5% e 4%, respectivamente, em relação à resistência a insulina, insulina, pressão arterial e glicemia. Para colesterol total, insulina, HOMA-IR e estado nutricional, RS/SP>BP (pEU>BP (pFUNDAMENTO: Análisis de las alteraciones metabólicas y de composición corporal en adolescentes. OBJETIVO: Estudiar la correlación entre niveles séricos de lípidos, glucemia, insulina, homocisteína, HOMA-IR y presión arterial, entre si y con variables corporales. MÉTODOS: Se recolectaron datos referentes a glucemia, colesterol total y fracciones (LDL, HDL y VLDL, triacilgliceroles, insulina, homocisteína y presión arterial en 100 adolescentes de 14 a 17 años de escuelas públicas de Viçosa (MG que ya habían presentado la menarca. El porcentaje de grasa corporal (%GC se evaluó por la bioimpedancia horizontal. RESULTADOS: Con relación al estado nutricional, el 83%, el 11% y el 6%, respectivamente, presentaron eutrofia (EU, riesgo de sobrepeso/sobrepeso (RS/SP y

  3. RELACIÓN ENTRE DIFERENTES PRUEBAS DE CAMPO: FUERZA, POTENCIA Y VELOCIDAD

    Directory of Open Access Journals (Sweden)

    Jessenia Hernández Elizondo

    2003-12-01

    Full Text Available Esta investigación tuvo como propósito principal el encontrar por medio de pruebas en las variables de fuerza, potencia y velocidad, la relación matemática existente entre estos tres constructos. Participaron 56 sujetos varones con edades entre 18 y 25 años. Con el fin de responder al objetivo del estudio, se les aplicaron pruebas de campo de fuerza (1RM de sentadilla completa y repeticiones máximas al 80% 60% 40% y 20%, de velocidad (30 metros lanzados y 30 metros sin impulso, y de potencia (salto vertical con contra-movimiento SVCM, salto vertical sin impulso SVSI y salto vertical con caída SVCC, para correlacionar las diferentes pruebas entre sí. Los datos fueron analizados por medio de la correlación de Pearson (r, para correlacionar parejas de pruebas y correlación canónica (Rc para correlacionar grupos de variables. A partir de cada correlación se obtuvo la varianza explicada (r2 la cual indica el porcentaje de relación compartida en escala de 0-100 que existe entre las pruebas. Según los datos obtenidos, no existe relación significativa (2.1% entre las pruebas de salto-sentadilla, ni relación significativa (5.1% entre las pruebas de velocidad- sentadilla, mientras que la relación salto- velocidad (62%, fue estadísticamente significativa (p < 0.05. La implicación de estos resultados podrían respaldar la idea de que la relación teórica que existe entre estos constructos, no es completamente cierta cuando éstos son medidos por medio de pruebas de campo.

  4. Investigation of hyperfine interactions in hafnium compounds with F1-, OH1-, and EDTA ligands by perturbed γ-γ angular correlation

    International Nuclear Information System (INIS)

    Amaral, Antonio A.; Silva, Andreia dos S.; Lapolli, Andre L.; Carbonari, Artur W.; Saxena, Rajendra N.

    2011-01-01

    In this study the hyperfine parameters, including the dynamical nature, Perturbed Angular Correlation (PAC) spectroscopy was used to measure the hyperfine parameters in molecules of ligand compounds in solutions. The measurements were carried out at 295 K and 77 K using 181 Hf → 181 Ta, as probe nuclei. Samples were prepared by adding a small volume of radioactive solution containing the probe nuclei in aqueous solution, buffer solution and ethylenediaminetetraacetic acid (EDTA) used as a ligand with pH between 4 and 5 which correspond to the pH of the saturated EDTA solution and in buffer solution with pH between 9 and 10. The results made possible to understand the impact of each method for PAC measurements. Finally a comparative analysis for the several methods of inserting of the probe nuclei in the sample was made, considering chemical and nuclear aspects. The lack of measurements in this kind of samples justifies the importance of the obtained results. (author)

  5. A desnecessidade do trabalho entre pescadores artesanais

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    Cristiano Wellington Norberto Ramalho

    2015-04-01

    Full Text Available As relações socioculturais e econômicas, entre alguns grupos de pescadores artesanais, não colocam como entes antagônicos trabalho e tempo livre. Do contrário, tais relações celebram aproximações entre saber-fazer pesqueiro, lazer e vida, formando e conformando um todo societário. Inseridos nesse quadro, estão os pescadores artesanais do mar-de-fora da praia de Suape, no município do Cabo de Santo Agostinho, litoral sul de Pernambuco, distante 50 km de Recife. Este artigo busca desvelar a mencionada moral do trabalho e do tempo livre no fazer cotidiano de pescadores dessa Praia, com base na pesquisa etnográfica e na história de vida de 13 pescadores. No geral, identificou-se que há uma moral do trabalho que se confunde à moral do tempo livre, pois o cerceamento de uma delas representa limites à outra. Assim, para esses homens, definir o que é um ser liberto ou cativo liga-se ao encontro indissociável, em termos práticos e simbólicos, entre as referidas morais, o que é essencial para classificar o fazer-se pescador artesanal em seu sentido pleno fundamentado na desnecessidade do trabalho.

  6. El (los Sur buscando al Sur. Una construcción entre estereotipos y realidad.

    Directory of Open Access Journals (Sweden)

    Mabel Franzone

    2010-11-01

    Full Text Available Todas las lecturas que podamos hacer del Sur, de sus propias representaciones, de aquellas vehiculizadas por el Norte, de sus creaciones, de sus reacciones, de su búsqueda constante de identidad, son lecturas de múltiples situaciones, que llaman a cruces insoslayables entre pueblos, entre distintas etnias, entre disciplinas, entre sentimientos que van desde el rechazo hasta la atracción casi magnética entre los dos hemisferios. Nuestra intención primera era la de reunir de manera aproximativa las problemáticas actuales de los Sur, ligadas a lo imaginario.

  7. Correlação entre hipótese diagnóstica e laudo de tomografia axial computadorizada craniana Correlation between diagnostic hypothesis and result of cranial computed axial tomography

    Directory of Open Access Journals (Sweden)

    Edison Matos Nóvak

    2001-09-01

    Full Text Available Para avaliar a utilização da tomografia axial computadorizada craniana (TC em nosso meio, analisamos as solicitações de 367 exames consecutivos no período compreendido entre 07/1995 e 07/1996. Houve ampla variação da faixa etária, com média de 31,7 ± 22,9 anos. As especialidades que mais solicitaram o exame foram: Neurologia (36,2%, Pronto Atendimento (17,4%, Neuropediatria (16,9% e Clínica Médica (5,9%. As indicações mais frequentes para o exame foram: convulsão (30%, cefaléia (26,2%, déficit motor (20,2% e redução do nível de consciência (16,9%. As "hipóteses" aventadas com maior frequência foram: afastar lesão estrutural (9,0%, acidente vascular não discriminado (8,2% e neurocisticercose (8,2%. O laudo da TC foi normal em 50,4% dos exames. Os laudos anormais mais frequentes foram: hidrocefalia (5,4%, acidente vascular isquêmico (5,4% e neoplasia (3,5%. As maiores taxas de achados normais foram encontradas nas "hipóteses" de cefaléia (94,4%, convulsão (71,4% e afastar lesão estrutural (66,7%. Os maiores índices de acerto entre hipótese e laudo foram encontrados nas situações de "afastar lesões estruturais" (66,7%, hidrocefalia (50%, acidente vascular cerebral isquêmico (50% e hematoma (50%. Concluimos que a utilização de um recurso auxiliar de diagnóstico como a TC cumpre melhor ainda a sua função se o requisitante do exame preencher com clareza e detalhamento o pedido do exame.The use of computed axial tomography (CT in the investigation of neurologic disorders is attractive for his disponibility in the health services. However, the indications of the exam and the correlation with the clinical features has not been frequently studied. We study correlation between the requests of CT and the findings reported by the radiologist, in 367 exams performed from 07/1995 to 07/ 1996. The mean age was 31.7 ± 22.9 years. The CT were requested in decrescent order of frequency by the Services of Neurology (36

  8. Entre ritmo e poesia: rap e literatura oral urbana

    Directory of Open Access Journals (Sweden)

    Marcus Rogerio Salgado

    2015-11-01

    Full Text Available O objetivo do presente artigo é um estudo do rap enquanto manifestação de literatura oral urbana e forma de oralidade tecnológica. Para tanto, o artigo passará em revista as relações entre literatura e palavra falada/cantada, assim como as possibilidades de interface estética entre a literatura e a música que estão em questão quando tratamos do rap.

  9. A FOTOGRAFIA ENTRE A ARTE POPULAR E A ARTE ERUDITA

    Directory of Open Access Journals (Sweden)

    Marcos Fabris

    2013-09-01

    Full Text Available Este artigo pretende discutir alguns dos aspectos que marcam o estabelecimento e a dissolução das fronteiras entre dois pólos convencionalmente descritos como arte culta e arte popular, tecendo paralelos entre o teatro de variedades, forma de expressão popular por excelência, e a fotografia, expressão artística que desde seus primórdios circula entre os dois extremos deste contínuo. Nestes termos, ambiciona-se verificar como determinadas condições sócio-históricas favorecem a criação de recursos formais que minimizam, ou suprimem, tais distinções consagradas pela crítica de arte.

  10. Proyectos educativos: estudio comparativo entre Venezuela y Colombia

    Directory of Open Access Journals (Sweden)

    Mineira Finol

    2005-09-01

    Full Text Available El Proyecto Educativo Integral Comunitario (PEIC y el Proyecto Educativo Institucional constituyen la categoría de comparación entre Venezuela y Colombia; a tal fin, este estudio de tipo comparativo-documental se centró en determinar congruencias y discrepancias entre PEIC y PEI, utilizando el método comparativo estructurado en cuatro fases: descripción, interpretación, yuxtaposición y comparación, propuesto por Hilker y Bereday (1972 Entre los resultados se tienen: congruencias en cuanto surgen sobre las bases de diagnóstico externos efectuados por organismos internacionales UNESCO, CEPAL ante la inefectividad y baja productividad de ambos países; a nivel interno responden a políticas educativas reformadoras de currículum y leyes,. Discrepancias referidas al tiempo de implementación; en Venezuela a partir de 1996; Colombia en 1992; este último, consolidó las bases para la participación a través del gobierno escolar y de un sistema de evaluación institucional, muy incipiente en Venezuela.

  11. X-ray tube targets

    International Nuclear Information System (INIS)

    Hirsch, H.H.

    1980-01-01

    In rotary targets for X-ray tubes warping is a problem which causes X-ray deficiency. A rotary target is described in which warping is reduced by using alloys of molybdenum with 0.05 to 10% iron, silicon, cobalt, tantalum, niobium, hafnium, stable metal oxide or mixture thereof. Suitable mixtures are 0.5 to 10% of tantalum, niobium or hafnium with from 0.5 to 5% yttrium oxide, or 0.05 to 0.3% of cobalt or silicon. Optionally 0.1 to 5% by weight of additional material may be alloyed with the molybdenum, such as tantalum or hafnium carbides. (author)

  12. Correlações simples entre as medidas de ultra-som e a composição da carcaça de bovinos jovens Correlations between ultrasound measurements and carcass composition of young bulls

    Directory of Open Access Journals (Sweden)

    Liliane Suguisawa

    2006-02-01

    Full Text Available Neste estudo avaliaram-se as correlações entre as medidas ultra-sonográficas e as características de carcaça de 115 bovinos jovens (Nelore, ½ Angus Nelore, ½ Simental Nelore e Canchim, com peso inicial médio de 329 kg e dois tamanhos à maturidade (pequeno e grande, em um sistema de produção do novilho superprecoce. Aos 120 dias de confinamento, foram realizadas a pesagem e medida da área de olho-de-lombo (AOL e da gordura subcutânea (ECG, via ultra-sonografia. Após o abate, foram coletadas as medidas de AOL e ECG na carcaça e os pesos de traseiro, dianteiro e cortes cárneos comerciais, determinando-se também a composição corporal dos animais. Foram calculados os rendimentos de carcaça, cortes cárneos, traseiro, da AOL ultra-som por 100 kg de PV e da AOL carcaça por 100 kg de peso de carcaça. Dados da composição da carcaça indicaram alta deposição muscular nos animais ½ Simental Nelore e Canchim e expressiva deposição de tecido adiposo nos animais Nelore. No entanto, os animais ½ Angus Nelore mostraram-se mais apropriados para confinamento no sistema de produção do superprecoce, pois equilibraram musculosidade e gordura de acabamento. Os resultados demonstraram que a AOL tem relação com a musculosidade da carcaça e que, à medida que há seleção para o incremento desta característica, ocorre diminuição da ECG, como resultado da correlação negativa da ECG com a porcentagem de traseiro e AOL. Não foi observada diferença na composição entre os dois grupos de tamanho à maturidade, provavelmente em razão da pequena variação entre eles. Como as correlações envolvendo a AOL e a ECG por ultra-som e as mesmas medidas na carcaça apresentam resultados similares, validou-se a utilização da técnica da ultra-sonografia como alternativa para predição das características da carcaça de bovinos.The objective of this study was to evaluate correlations between ultrasonography measurements and carcass

  13. Consumo de álcool e violência entre adolescentes argentinos

    Directory of Open Access Journals (Sweden)

    Mariaelena Pierobon

    2013-02-01

    Full Text Available OBJETIVO: Este estudo investigou a associação entre álcool e violência na população de jovens argentinos. MÉTODOS: Dados da Global School-based Student Health Survey (GSHS de 2007, uma pesquisa representativa em termos nacionais com alunos do ensino médio, foram examinados utilizando-se modelos de regressão logística ajustados por idade. RESULTADOS: Dos 1328 alunos participantes entre 13 e 15 anos de idade, 51,9% declararam ter consumido álcool no último mês, com taxas mais elevadas entre meninos (p = 0,04 e alunos mais velhos (p < 0,01. Homens e mulheres que bebem demonstraram estar quase duas vezes mais propensos a relatar agressão física, quando em uma briga física, e pensamentos sobre violência autoinfligida do que aqueles que não bebem. Entre as pessoas que bebem, aquelas que reportaram saúde mental precária, haviam sido vítimas de bullying, fumavam, faziam uso de drogas ou abandonaram a escola sem permissão se mostraram duas vezes mais propensas ao envolvimento em atividades violentas do que outras pessoas que também bebem. CONCLUSÃO: Intervenções de saúde pública quanto à violência entre jovens adolescentes devem ser desenvolvidas em combinação com programas de educação sobre álcool.

  14. Analyse de régression quantile de la relation entre la langue et l’intervalle entre les grossesses au Québec (Canada

    Directory of Open Access Journals (Sweden)

    Nathalie Auger

    2018-01-01

    Full Text Available Introduction. On sait que les intervalles courts comme les intervalles longs entre les grossesses sont associés à des issues périnatales défavorables, comme des fausses couches et des accouchements prématurés, mais les différences culturelles à ce sujet sont mal connues. Repérer les inégalités culturelles dans les intervalles entre les grossesses est nécessaire afin d'améliorer les résultats relatifs à la santé de la mère et de l’enfant. Nous avons ainsi évalué les intervalles entre les grossesses chez les anglophones et les francophones du Québec. Méthodologie. Nous avons obtenu les dossiers de naissance de tous les enfants nés au Québec entre 1989 et 2011. Nous avons recensé 571 461 femmes ayant eu au moins deux naissances et déterminé l’intervalle entre leurs grossesses. Les intervalles courts entre les grossesses (moins de 18 mois ont été définis comme étant le 20e percentile de la distribution, et les intervalles longs (60 mois ou plus, comme le 80e percentile. À l’aide de régressions quantiles, nous avons évalué l’association entre la langue et les intervalles courts et longs, ajustés en fonction des caractéristiques de la mère. Nous avons évalué les différences au fil du temps et selon l’âge de la mère pour les groupes défavorisés, qui ont été définis par l’absence de diplôme d’études secondaires, la résidence en milieu rural et le fait de vivre dans un quartier défavorisé matériellement. Résultats. Dans les modèles de régression ajustés, les anglophones sans diplôme d’études secondaires avaient des intervalles plus courts de 1,0 mois (intervalle de confiance [IC] à 95 % : −1,5 à −0,4 par rapport à leurs homologues francophones au 20e percentile de la distribution et plus longs de 1,9 mois (−0,5 à 4,3 au 80e percentile. Les résultats étaient similaires pour les anglophones des régions rurales et des quartiers matériellement défavorisés. Les

  15. Intra-familial physical violence among Mexican and Egyptian youth Violência física intra-familiar entre jovens mexicanos e egípcios

    Directory of Open Access Journals (Sweden)

    Leonor Rivera-Rivera

    2005-10-01

    Full Text Available OBJECTIVE: To determine the prevalence of experiencing intra-familial violence among Mexican and Egyptian youth and to describe its associated risk factors. METHODS: Data from questionnaires applied to 12,862 Mexican and 5,662 Egyptian youth, aged 10 to 19, who attended public schools were analyzed. Biviarate and logistic regression analysis were used to determine the relationship between socio-demographics, the experience of intra-familial violence and violence perpetration. RESULTS: The prevalence of having experienced intra-familial violence was comparable across the Mexican and Egyptian populations (14% and 17%, respectively. In Mexico, young men were more likely to have experienced such violence (OR=2.36 than women, whereas in Egypt, young women were at slightly greater risk than young men (OR=1.25. Older age, male gender and urban residence were independent correlates of experiencing intra-familial violence among Mexican youth. For Egyptian adolescents, in contrast, younger age, female gender and having non-married parents were independent correlates of victimization. Intra-familial violence victims were also more likely than non-victims to perpetrate violence (Mexico: OR=13.13; Egypt: OR=6.58. CONCLUSIONS: Mexican and Egyptian youth experienced intra-familial violence at a relatively low prevalence when compared with youth of other countries. A strong association was found between experiencing intra-familial violence and perpetrating violence.OBJETIVO: Determinar a prevalência da violência intra-familiar sofrida por jovens mexicanos e egípcios, e descrever os fatores de risco associados. MÉTODOS: Os dados analisados foram obtidos de questionários aplicados a 12.862 mexicanos e 5.662 egípcios, jovens de 10 a 19 anos, que freqüentam escolas públicas. O relacionamento entre fatores sociodemográficos, a violência sofrida e sua perpetração foram investigados por meio de análise bivariada e regressão logística. RESULTADOS: A

  16. 40 CFR 421.332 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Science.gov (United States)

    2010-07-01

    ... times. (d) SiCl4 purification wet air pollution control. BPT Limitations for the Primary Zirconium and...) Sand drying wet air pollution control. BPT Limitations for the Primary Zirconium and Hafnium... chlorination off-gas wet air pollution control. BPT Limitations for the Primary Zirconium and Hafnium...

  17. Soporte social, familiar y autoconcepto: relación entre los constructos

    Directory of Open Access Journals (Sweden)

    Makilim Nunes Baptista

    2012-01-01

    Full Text Available El objetivo del estudio fue verificar las asociaciones entre el soporte social, el soporte familiar y el autoconcepto en un grupo de hombres y mujeres. En el caso de los hombres hubo correlaciones negativas entre el soporte familiar y los factores negligencia, agresividad e indiferencia del instrumento de autoconcepto. En el grupo de mujeres el soporte familiar total fue correlacionado positivamente con sensualidad y responsabilidad, y negativamente con inseguridad, siendo las tres medidas del instrumento de autoconcepto. Al considerar las relaciones entre el soporte familiar y el soporte social, todas fueron positivas, tanto en los hombres como en las mujeres.

  18. PENGARUH PANJANG ENTRES TERHADAP KEBERHASILAN PENYAMBUNGAN TANAMAN ALPUKAT (PERSEA AMERICANA MILL.

    Directory of Open Access Journals (Sweden)

    Dirgahani Putri

    2016-06-01

    Full Text Available Beragamnya hasil produksi dan kualitas buah alpukat dapat diperbaiki dengan metode penyambungan. Penyambungan merupakan kegiatan untuk mengga-bungkan dua atau lebih sifat unggul dalam satu tanaman. Penelitian ini bertujuan mengetahui pengaruh berbagai panjang entres terhadap keberhasilan penyam-bungan tanaman alpukat. Rancangan percobaan yang digunakan dalam penelitian ini adalah Rancangan Acak Kelompok dengan lima perlakuan panjang entres, yaitu 3 cm, 6 cm, 9 cm, 12 cm, dan 15 cm.Setiap perlakuan diulang sebanyak lima kali dan setiap perlakuan terdiri atas lima tanaman;sehingga jumlah totalnya sebanyak 125 tanaman. Pengamatan dilakukan pada peubah persentase sambung hidup, jumlah tunas, panjang tunas, jumlah daun, dan diameter batang atas. Berbagai panjang entres tidak memberikan pengaruh yang nyata pada peubah persentase sambung hidup, panjang tunas terpanjang, jumlah daun, dan diameter batang atas tetapi berpengaruh nyata pada peubah jumlah tunas. Perlakuan panjang entres 15 cm memberikan hasil tertinggi untuk jumlah tunas, panjang tunas, jumlah daun dan diameter batang atas, sedangkan untuk persentase hidup perlakuan 6 cm, 12 cm memberikan hasil tertinggi yaitu 100%. Perlakuan panjang entres 3 cm adalah perlakuan yang memberikan pengaruh yang rendah pada persentase sambung hidup (yaitu 92%, peubah jumlah tunas, panjang tunas, serta diameter batang atas pada berbagai umur tanaman alpukat.

  19. Aborto entre alunas e funcionárias de uma universidade brasileira

    Directory of Open Access Journals (Sweden)

    Hardy Ellen

    1993-01-01

    Full Text Available No Brasil existem poucas informações sobre o aborto provocado e suas características na população. A dificuldade em se obter dados confiáveis deve-se: à sua ilegalidade, e também ao fato de que a maioria dos estudos é realizada em hospitais. Assim, em 1990, foi realizada pesquisa entre alunas da graduação e funcionárias de uma universidade brasileira. Os dados foram obtidos por meio de questionário, auto-respondido, para devolução por correio, anonimamente. Os resultados apresentados referem-se à freqüência do aborto provocado nesta população. Encontrou-se que quatro vezes menos alunas do que funcionárias tinham engravidado alguma vez (15% e 65%; 9% das alunas e 14% das funcionárias tiveram aborto provocado. Entre as mulheres que engravidaram alguma vez, as alunas tiveram mais aborto provocado do que as funcionárias (59% e 20%. Quando controladas por grupo etário as diferenças entre as alunas e funcionárias mantiveram-se. Entretanto, entre as alunas, o aborto provocado foi mais freqüente entre as mais jovens.

  20. Electrochemical-metallothermic reduction of zirconium in molten salt solutions

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Talko, F.

    1990-01-01

    This patent describes a method for separating hafnium from zirconium of the type wherein a feed containing zirconium and hafnium chlorides is prepared from zirconium-hafnium chloride and the feed is introduced into a distillation column, which distillation column has a reboiler connected at the bottom and a reflux condenser connected at the top and wherein a hafnium chloride enriched stream is taken from the top of the column and a zirconium enriched chloride stream is taken from the bottom of the column. It comprises: reducing the zirconium enriched chloride stream taken from the distillation column to metal by electrochemically reducing an alkaline earth metal in a molten salt bath with the molten salt in the molten salt bath consisting essentially of a mixture of at least one alkali metal chloride and at least one alkaline earth metal chloride and zirconium chloride, with the reduced alkaline earth metal reacting with the zirconium chloride to produce zirconium metal and alkaline earth metal chloride

  1. Encuentros improbables: Cervantes y Shakespeare entre Borges y Burgess

    OpenAIRE

    Martínez, Zenón Luis

    2016-01-01

    En sus biografías sobre Cervantes y Shakespeare, Luis Astrana Marín especuló con un encuentro entre ambos con ocasión de la ratificación en 1605 en Valladolid del Tratado de Londres. Este improbable encuentro ha seguido alimentando ficciones históricas y fantasías literarias. El cruce de caminos entre Cervantes y Shakespeare tiene lugar en torno a la perdida tragicomedia The History of Cardenio (1612?), atribuida a John Fletcher y William Shakespeare. La recon...

  2. La religiosidad popular como “entre-medio” entre la religión institucional y la espiritualidad individualizada = Popular religion as “in between” institutional religion and individual spirituality

    Directory of Open Access Journals (Sweden)

    Torre, Renée de la

    2012-01-01

    Full Text Available Neste artigo se argumenta a relevância do estudo da religiosidade popular para entender as novas formas da religiosidade contemporânea no contexto latinoamericano. Diferente das posturas teóricas dos sociólogos da religião europeia, que assinalam a pertinência do indivíduo como unidade analítica para entender as transformações religiosas próprias da pós-modernidade, este artigo argumenta que a religiosidade popular – entendida como “entre-meio” entre o tradicional e o emergente, entre o local e o transnacional, entre o social e o individual e entre a sacralidade profana e a profanação da religiosidade tradicional – permite entender os fenômenos em que a religiosidade se pratica nas margens da instituição (próprias das expressões new age e neoesotéricas, mas sem desatender os processos em que se legitimam as novas formas desinstitucionalizadas da religiosidade, buscando âncoras e linhagens que geram a continuidade do peso da tradição da religiosidade popular

  3. Relación entre calidad del semen y la edad

    Directory of Open Access Journals (Sweden)

    John Chávez

    2012-07-01

    Full Text Available Objetivo: Determinar la relación entre la calidad del semen humano y la edad. Material y Métodos: El espermatograma se realizó siguiendo el Manual de Laboratorio de la OMS para el examen del Semen Humano y de la Interacción Moco Cervical y Semen (1999, de los exámenes realizados entre julio 2003 a diciembre 2008. Se estudiaron 2 441 casos de varones que cumplen con los criterios de inclusión. Resultados: La motilidad A+B fue de 51,55% para varones de 20 a 29 años; los espermatozoides normales fue de 77,73% para varones mayores de 50 años; el recuento espermático (mill/ml fue de 61,09 para varones mayores de 50 años.La evaluación de la motilidad espermática tuvo como coeficiente de correlación lineal múltiple de 0,222 y coeficiente de determinación de 0,049; en la morfología espermática, coeficiente de correlación lineal de 0,0622 y coeficiente de determinación de 0,0039; en el recuento espermático, coeficiente de correlación lineal múltiple de 0,465 y coeficiente de determinación de 0,216. Conclusiones: existe una tendencia inversa entre la motilidad y la edad, una tendencia directa entre el recuento espermático y la edad, y una tendencia constante entre morfología espermática y edad.

  4. relaPro : Base de datos para encontrar relaciones entre proyectos

    OpenAIRE

    Fortis Urbano, Julio

    2015-01-01

    Desarrollo de una base de datos para almacenar proyectos y una aplicación web de ejemplo que permite encontrar elementos comunes entre los proyectos almacenados en el sistema. Desenvolupament d'una base de dades per emmagatzemar projectes i una aplicació web d'exemple que permet trobar elements comuns entre els projectes emmagatzemats en el sistema. Bachelor thesis for the Computer Science program on Databases.

  5. Relación entre el feedback emocional, feedback cognitivo-verbal y percepción emocional en la variante frontal de demencia frontotemporal resultados preliminares Relationship Between Emotional Feedback, Verbal-Cognitive Feedback And Emotional Perception In The Frontal Variant Of Frontotemporal Dementia Preliminary Results

    Directory of Open Access Journals (Sweden)

    Florencia Calodolce

    2008-12-01

    Full Text Available Numerosos estudios hallaron disociaciones, tanto entre las pruebas de cognición social entre sí, como entre éstas y las que evalúan funciones ejecutivas, lo cual apoya la idea de que el feedback emocional, la percepción emocional y el feedback cognitivo-verbal constituyen dominios cognitivos independientes. Sin embargo en la literatura actual existe controversia respecto de aquella disociación. Con el objetivo de estudiar dicha relación se evaluaron 15 sujetos con variante frontal de Demencia Frontotemporal (DFTvf con una batería neuropsicológica, y además utilizando: Wisconsin Card Sorting Test (WCST, Iowa Gamblig Task (IGT y Test de Lectura de Mente en Ojos (LMO. Se encontró un correlación inversa entre IGT y WCST, correlación directa entre LMO y WCST y falta de correlación entre IGT y LMO. Estos resultados apoyan la hipótesis de que los dominios cognitivos estudiados se encuentran disociados (Bechara, A., Damasio, A.R. y Lough, S..Several studies found dissociations, both between social cognition tests among themselves, and between these and those evaluating executive functions, which supports the idea that emotional feedback, emotional perception and verbal-cognitive feedback are independent cognitive domains. Nevertheless in present literature there is a controversy respect to that dissosciation. With the objective to study the relation between these processes a group of 15 subjects with frontal variant of Frontotemporal Dementia (DFTvf, was evaluated with a neuropsycological battery and in addition using: Wisconsin Card Sorting Test (WCST, Iowa Gamblig Task (IGT and The Reading the mind in Eyes Test (LMO. There was found: an inverse correlation between IGT and WCST, a direct correlation between LMO and WCST and a lack of correlation between IGT and LMO. These results support the hypothesis that the studied cognitive domains are dissociated (Bechara,A., Damasio, A.R. y Lough, S..

  6. Cooperación; altruismo en las relaciones entre aerolíneas

    OpenAIRE

    Fernández Lerate, Elisa M.

    2016-01-01

    El presente estudio se centra en analizar unas determinadas relaciones cooperativas entre compañías aéreas, con la intención de investigar si sacan provecho o no de dichas relaciones. La cooperación entre esas compañías aéreas puede presentar comportamientos más altruistas o más oportunistas. Para centrar el tema del estudio, se van a analizar los acuerdos de códigos compartidos que llevan a cabo entre ellas. Los datos de cooperación a través de código compartido permitirán conocer qué porcen...

  7. Determination of hafnium at the 10−4% level (relative to zirconium content) using neutron activation analysis, inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Smolik, Marek; Polkowska-Motrenko, Halina; Hubicki, Zbigniew; Jakóbik-Kolon, Agata; Danko, Bożena

    2014-01-01

    Graphical abstract: -- Highlights: •We worked out ICP-MS method of Hf determination in Zr and Zr compounds. •We used NAA method as reference one. •We obtained pure zirconium matrix by ion exchange (Diphonix ® resin). •These permit to determine ≥1 × 10 −4 % Hf in Zr sample by ICP MS with good precision and accuracy. -- Abstract: Hafnium at the very low level of 1–8 ppm (in relation to zirconium) was determined in zirconium sulfate solutions (originating from investigations of the separation of ca. 44 ppm Hf from zirconium by means of the ion exchange method) by using three independent methods: inductively coupled plasma mass spectrometry (ICP MS), neutron activation analysis (NAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of NAA and ICP MS determinations were consistent with each other across the entire investigated range (the RSD of both methods did not exceed 38%). The results of ICP-AES determination were more diverse, particularly at less than 5 ppm Hf (RSD was significantly higher: 29–253%). The ion exchange method exploiting Diphonix ® resin proved sufficient efficiency in Zr–Hf separation when the initial concentration ratio of the elements ([Zr] 0 /[Hf] 0 ) ranged from 1200 to ca. 143,000

  8. Las relaciones de comercio e inversión entre Colombia y Venezuela

    OpenAIRE

    Eglé Iturbe de Blanco

    1997-01-01

    Venezuela y Colombia cuentan con una larga trayectoria histórica en sus relaciones económicas. Comercian entre ellas y sus nacionales a lo largo de la frontera desde su nacimiento como naciones e interactúan entre ambos países como si fuera uno solo. Al norte, en la península de la Guajira, viven poblaciones indígenas comunes cuyo sustento es el comercio entre ambos lados de la frontera; y al sur, en los estados andinos venezolanos limítrofes con los llanos colombianos, tradicionalmente se ha...

  9. Relaciones entre los salarios y la productividad en Colombia

    OpenAIRE

    Méndez Sayago, Jhon Alexander

    2017-01-01

    Esta tesis de doctorado está compuesta de cuatro artículos que tienen como propósito estudiar las relaciones entre los salarios y la productividad laboral en Colombia. Los dos primeros artículos denominados “Salario real y eficiencia del trabajo en el sector manufacturero en Colombia” y “Análisis de causalidad y sensibilidad entre los salarios reales y la productividad laboral en el sector manufacturero a partir de cifras de los departamentos en Colombia” aportan evidencia empírica sobre la d...

  10. Correlation between honey production and some morphological traits in africanized honey bees (Apis melifera Correlação entre a produção de mel e algumas características morfologicas em abelhas africanizadas (Apis mellifera

    Directory of Open Access Journals (Sweden)

    Darcet Costa Souza

    2002-10-01

    Full Text Available This study focused on the correlation between honey production length and width of the tibia of the third pair of legs, corbicular area, pupal weight, and glossal length, in Africanized honey bees in Viçosa/MG, Brazil. Correlation values were relatively low, though always positive. The traits glossal length and pupal weight presented the lowest correlation to honey production: 0.225 and 0.410, respectively. The highest correlations were observed between length of the tibia and corbicular area and honey production: 0.587 and 0.549, respectively. In all cases, except pupal weight, correlation was significant. These findings support the notion that worker bees with larger corbicular areas may have a better ability to carry larger quantities of pollen to their hives, so that it is possible to improve honey production through indirect selection of this trait.Foram estimadas as correlações entre as características produção de mel, comprimento e largura da tíbia do terceiro par de patas, área corbicular, peso pupal e comprimento da glossa de abelhas africanizadas em Viçosa/MG. Os valores das correlações foram relativamente baixos, embora todos positivos. As características peso pupal e comprimento da glossa foram as que menos se correlacionaram com a produção de mel, 0,225 e 0,410, respectivamente. A área corbicular e o comprimento da tíbia foram as mais correlacionadas com a produção de mel, 0,587 e 0,549, respectivamente. Todas as correlações, exceto o peso pupal, foram significativas. O trabalho dá suporte à idéia de que operárias de maiores áreas corbiculares são mais hábeis a levar mais pólen para suas colméias, sendo possível a obtenção de ganhos na produção de mel, por meio de uma seleção indireta nesta característica.

  11. Report a possible correlation between necrotizing ulcerative gingivitis and mononucleosis Reporte de una posible correlación entre la gingivitis ulceronecrotizante y la mononucleosis

    Directory of Open Access Journals (Sweden)

    Rosa Francinne Miranda

    2011-12-01

    Full Text Available Necrotizing ulcerative gingivitis is a relatively uncommon periodontal disease, characterized by ulceration, necrosis, pain and gingival bleeding. Factors often related to its occurrence include stress and systemic viral infections, such as those caused by cytomegalovirus and Epstein-Barr virus type 1, the latter being also considered the causative agent of infectious mononucleosis. This article aims to describe a clinical case of a female patient who presented with necrotizing ulcerative gingivitis associated with a clinical picture of infectious mononucleosis, as well as to review the literature concerning a possible correlation between these pathologies. This patient presented to our health care facility with necrotizing ulcerative gingivitis accompanied by lymphadenopathy, fever and prostration, after laboratory tests, Epstein-Barr virus type 1 infection was confirmed, as well as the co-occurrence of pathologies: necrotizing ulcerative gingivitis and infectious mononucleosis. Symptom remission in both disorders also occurred concomitantly, after instruction in plaque control measures and palliative medication for control of systemic symptoms. Therefore, although there is no scientific validation of an association between these two pathologies, it is imperative that all diagnostic alternatives be considered and investigated, in order to establish the therapeutic approach most appropriate to the patient.La gingivitis ulcerativa necrótica es una enfermedad periodontal no común caracterizada por ulceración, necrosis, dolor y sangrado gingival. Los factores a menudo relacionados con su ocurrencia incluyen el estrés y las infecciones virales sistémicas como aquellas causadas por Cytomegalovirus y el virus Epstein-Barr tipo 1, donde este último es el agente causal de la mononuclerosis infecciosa. El objetivo de este trabajo fue describir el caso clínico de una mujer con gingivitis ulcerativa necrótica asociada a un cuadro clínico de

  12. Relación entre inteligencia emocional, depresión y rendimiento académico en estudiantes de psicología

    Directory of Open Access Journals (Sweden)

    Ubaldo Rodríguez de Alba

    2012-07-01

    Full Text Available Abstract This research paper is part of the funded project on emotional intelligence in the II internal meeting of University of Magdalena (Ref: II CSI-11-2010 -2012. It is a descriptive-correlational and cross-sectional design. Its main objective was to identify the relationship between Perceived Emotional Intelligence (EI, depression and academic performance in Psychology students of Santa Marta (Colombia. The study involved 76 students who applied the Beck depression inventory, the Trait Meta Mood Scale. Academic performance is registered through the academic GPA. The results indicated significant negative relationship between the emotional clarity, emotional repair and levels of depression, as well as non-existence of significant relationship between the skills of EI and the academic performance; however, the latter negatively correlate with the levels of depression. Resumen El presente artículo de investigación se enmarca en el proyecto sobre inteligencia emocional financiado en la II convocatoria interna del programa Semilleros de la Universidad del Magdalena (Ref: II CSI-11-2010-2012. Es de tipo descriptivo-correlacional y de diseño transversal. Su objetivo principal consistió en identificar la relación entre la Inteligencia Emocional Percibida (IE, depresión y rendimiento académico en estudiantes de Psicología de Santa Marta (Colombia. En el estudio participaron 76 estudiantes a los que se aplicó el inventario para la depresión de Beck, el Trait Meta Mood Scale. El rendimiento académico se registró a través de los promedios académicos ponderados. Los resultados indicaron relación negativa significativa entre la claridad emocional, la reparación emocional y los niveles de depresión, así como la no existencia de relación significativa entre las habilidades de IE y el rendimiento académico; sin embargo, este último sí se correlaciona negativamente con los niveles de depresión.

  13. Hierarchical structure of genetic distances: Effects of matrix size, spatial distribution and correlation structure among gene frequencies

    Directory of Open Access Journals (Sweden)

    Flávia Melo Rodrigues

    1998-06-01

    Full Text Available Geographic structure of genetic distances among local populations within species, based on allozyme data, has usually been evaluated by estimating genetic distances clustered with hierarchical algorithms, such as the unweighted pair-group method by arithmetic averages (UPGMA. The distortion produced in the clustering process is estimated by the cophenetic correlation coefficient. This hierarchical approach, however, can fail to produce an accurate representation of genetic distances among populations in a low dimensional space, especially when continuous (clinal or reticulate patterns of variation exist. In the present study, we analyzed 50 genetic distance matrices from the literature, for animal taxa ranging from Platyhelminthes to Mammalia, in order to determine in which situations the UPGMA is useful to understand patterns of genetic variation among populations. The cophenetic correlation coefficients, derived from UPGMA based on three types of genetic distance coefficients, were correlated with other parameters of each matrix, including number of populations, loci, alleles, maximum geographic distance among populations, relative magnitude of the first eigenvalue of covariance matrix among alleles and logarithm of body size. Most cophenetic correlations were higher than 0.80, and the highest values appeared for Nei's and Rogers' genetic distances. The relationship between cophenetic correlation coefficients and the other parameters analyzed was defined by an "envelope space", forming triangles in which higher values of cophenetic correlations are found for higher values in the parameters, though low values do not necessarily correspond to high cophenetic correlations. We concluded that UPGMA is useful to describe genetic distances based on large distance matrices (both in terms of elevated number of populations or alleles, when dimensionality of the system is low (matrices with large first eigenvalues or when local populations are separated

  14. Empirical correlation among the dynamic elastic constants and the waves P and S velocities in rocks; Correlaciones empiricas entre las constantes elasticas dinamicas y las velocidades de las ondas P y S de las rocas

    Energy Technology Data Exchange (ETDEWEB)

    Contreras Lopez, Enrique [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    Departing from the analysis of a data base on the velocities of the compression waves (V{sub p}) and the transverse waves (V{sub s}) in a group of 97 specimens of sedimentary, igneous and metamorphic rocks, the existence of four types of empirical correlation very well entailed between the dynamic elastic constants and the velocities V{sub p} and V{sub s}. These correlation allow the estimation with a very close approximation the elastic dynamic constants without the need of having available of the complete set of data (V{sub p}, V{sub s} and total density) that is normally required for its determination. The identified correlation is mathematically expressed by means of adjustment equations that reproduce in all of the cases the experimental values with a standard error of estimation within 10%, for the universe of rocks studied and with much less error for different specific lithological groups. The application methodologies of the correlation found for different cases of practical interest, are described. [Espanol] A partir del analisis de una base de datos experimentales sobre la velocidad de las ondas compresionales (V{sub p}) y de las ondas transversales (V{sub s}) de un conjunto de 97 especimenes de rocas sedimentarias, igneas y metamorficas, se identifica la existencia de cuatro tipos de correlaciones empiricas muy bien comportadas entre las constantes elasticas dinamicas y las velocidades V{sub p} y V{sub s}. Estas correlaciones permiten estimar con muy buena aproximacion las constantes elasticas dinamicas de las rocas sin tener que disponer del conjunto completo de datos (V{sub p}, V{sub s} y densidad total) que normalmente se requieren para su determinacion. Las correlaciones identificadas se expresan matematicamente mediante ecuaciones de ajuste que reproducen en todos los casos los valores experimentales con un error estandar de estimacion dentro de 10% para el universo de las rocas estudiadas, y con mucho menor error para diferentes grupos litologicos

  15. Empirical correlation among the dynamic elastic constants and the waves P and S velocities in rocks; Correlaciones empiricas entre las constantes elasticas dinamicas y las velocidades de las ondas P y S de las rocas

    Energy Technology Data Exchange (ETDEWEB)

    Contreras Lopez, Enrique [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    Departing from the analysis of a data base on the velocities of the compression waves (V{sub p}) and the transverse waves (V{sub s}) in a group of 97 specimens of sedimentary, igneous and metamorphic rocks, the existence of four types of empirical correlation very well entailed between the dynamic elastic constants and the velocities V{sub p} and V{sub s}. These correlation allow the estimation with a very close approximation the elastic dynamic constants without the need of having available of the complete set of data (V{sub p}, V{sub s} and total density) that is normally required for its determination. The identified correlation is mathematically expressed by means of adjustment equations that reproduce in all of the cases the experimental values with a standard error of estimation within 10%, for the universe of rocks studied and with much less error for different specific lithological groups. The application methodologies of the correlation found for different cases of practical interest, are described. [Espanol] A partir del analisis de una base de datos experimentales sobre la velocidad de las ondas compresionales (V{sub p}) y de las ondas transversales (V{sub s}) de un conjunto de 97 especimenes de rocas sedimentarias, igneas y metamorficas, se identifica la existencia de cuatro tipos de correlaciones empiricas muy bien comportadas entre las constantes elasticas dinamicas y las velocidades V{sub p} y V{sub s}. Estas correlaciones permiten estimar con muy buena aproximacion las constantes elasticas dinamicas de las rocas sin tener que disponer del conjunto completo de datos (V{sub p}, V{sub s} y densidad total) que normalmente se requieren para su determinacion. Las correlaciones identificadas se expresan matematicamente mediante ecuaciones de ajuste que reproducen en todos los casos los valores experimentales con un error estandar de estimacion dentro de 10% para el universo de las rocas estudiadas, y con mucho menor error para diferentes grupos litologicos

  16. Correlación entre homofobia y racismo en estudiantes de medicina

    Directory of Open Access Journals (Sweden)

    Adalberto Campo-Arias

    2014-01-01

    Full Text Available El objetivo de este estudio fue determinar la correlación entre homofobia y racismo en estudiantes de medicina de Bucaramanga (Colombia. Se realizó un estudio transversal que incluyó a estudiantes mayores de 18 años. La actitud hacia homosexuales (homofobia o prejuicio sexual se midió con la Escala de Homofobia (EHF y la actitud hacia afrocolombianos (el racismo o la discriminación racial, con una versión en español de la Escala de Racismo Moderno (MRS. La asociación entre homofobia y racismo se calculó con los coeficientes de Pearson (r y Spearman (rs. Un grupo de 334 estudiantes aceptó participar. La media para la edad fue 20,1 años (DE=1,9, 59,0 % eran mujeres. El alfa de Cronbach fue 0,78 para la EHF y 0,62 para la MRS. Las puntuaciones en la EHF fueron entre 7 y 34 (media=17,8; SD=5,4 y en la MRS, entre 0 y 34 (media=13,8; SD=5,2. El coeficiente r fue 0,35 (p<0,001 y rs, 0,34 (p<0,001. Se concluye que existe correlación positiva entre estas formas de prejuicio (la homofobia y el racismo en estudiantes de medicina de Bucaramanga. Se necesita una intervención para reducir los prejuicios en los estudiantes de medicina.

  17. Towards the anti-fibrillogenic activity of phthalocyanines with out-of-plane ligands: correlation with self-association proneness

    Directory of Open Access Journals (Sweden)

    Kovalska V. B.

    2013-11-01

    Full Text Available Aim. The activity of five hafnium phthalocyanines containing out-of-plane ligands as inhibitors of reaction of insulin fibril formation is studied and correlation between their inhibitory properties and tendency to self-association is discussed. Methods. Fluorescence and absorption spectroscopy. Results. For the complexes with weak proneness to self-association PcHfDbm2, PcHfPyr2, and PcHfBtfa2 the values of inhibitory activity were estimated as 60–73 %. For phthalocyanines with the pronounced tendency to self-association PcHfPiromelit and PcHfCl2 the noticeably higher inhibitory activity values (about 95 % were shown. In the presence of native or fibrilar insulin the destruction of self-associates of metal complex occurs in buffer pH 7.9, Besides upon the conditions of insulin fibrillization reaction (0.1 M HCl phthalocyanines exist predominantly as monomers. Conclusions. The phthalocyanines with out-of-plane ligands with higher tendency to self-association have shown higher inhibitory activity in the insulin fibril formation comparing with the poorly aggregated metal complexes. At the same time low-order self-associates are not involved directly in the mechanism of inhibition of insulin fibrillization and the phthalocyanines bind with protein in monomeric form. Tendency of phthalocyanines to self-association in aqueous media seems to be an «indicator» of their proneness to stack with protein aromatic amino-acids and thus of anti-fibrilogenic properties.

  18. Um mapeamento das aproximações entre Weber e Nietzsche

    Directory of Open Access Journals (Sweden)

    Leandro dos Santos

    2014-06-01

    Full Text Available Este artigo tem por objetivo um levantamento dos principais tópicos de aproximação entre a Sociologia de Max Weber (1864-1920 e a Filosofia de Friedrich W. Nietzsche (1844-1900. Para tanto, sublinharam-se os pontos mais expressivos e correntemente observados na literatura acerca das aproximações entre Weber e Nietzsche. Nesse sentido, os traços de maior afinidade foram encontrados nos seguintes temas: poder, conhecimento, modernidade e ética.

  19. Cyberbullying: competencia social, motivación y relaciones entre iguales

    Directory of Open Access Journals (Sweden)

    2016-07-01

    Full Text Available El reconocimiento de cierto solapamiento entre el acoso cara a cara (bullying y el ciberacoso (cyberbullying puede indicar que variables de cognición social, cuya influencia ha sido reconocida en el bullying, también estén presentes en el acoso cibernético. El objetivo de la investigación fue estudiar el ajuste social de los implicados en cyberbullying y analizar las diferencias en la percepción de la competencia social, la motivación y el apoyo de los iguales, entre víctimas, agresores y agresores victimizados del cyberbullying. Un total de 505 adolescentes (47,3% chicas con edades comprendidas entre los 12 y 16 años (M=13.95; DT=1.42 participaron en el estudio. Se utilizaron instrumentos para adolescentes validados en español y se analizaron las propiedades psicométricas para la adaptación de la escala de competencia social. Análisis factoriales exploratorios y confirmatorios mostraron índices óptimos de fiabilidad y validez. Se observó una mayor implicación de los ciberagresores victimizados. Las comparaciones entre roles a través de pruebas no paramétricas mostraron en los ciberagresores un mayor apoyo social que el resto de perfiles y altos niveles en metas de popularidad. Las cibervíctimas destacaron por su alta percepción de competencia social. Los ciberagresores victimizados mostraron altos niveles de metas de popularidad y baja aceptación social. Los resultados obtenidos permiten concluir que la forma en que el grupo de iguales gestiona su vida emocional y social puede estar explicando la situación de cyberbullying entre los adolescentes.

  20. Entre formigas e estrelas

    Directory of Open Access Journals (Sweden)

    Vinicius Prates

    2013-06-01

    Full Text Available Esta resenha apresenta o livro Reagregando o social: uma introdução à teoria do ator-rede, última obra do filósofo francês Bruno Latour publicada no Brasil. Nele, o autor se propõe a elaborar uma suma da crítica que faz aos conceitos usualmente aceitos de “social”, o que vem desenvolvendo ao longo dos últimos anos de produção intelectual. Neste processo ele criou a “Teoria-ator-rede”, que busca reestabelecer teoricamente as relações entre o que chama de mediadores “humanos” e “não-humanos”.

  1. Use of the on-line Moessbauer effect as a contribution to the study of recoil defects in solids

    International Nuclear Information System (INIS)

    Jeandey, Christian

    1974-01-01

    This research thesis addresses the study of effects of nuclear reactions, also known as 'after-effects' such as atomic disorders resulted from atom recoil, but also possible chemical modifications. The author more particularly focuses of recoil defects. He reports a critical review of studies of structure defects (in pure metals, ordered alloys, ionic crystals) performed by using conventional resonance absorption, and then presents an analysis of results of the defect creation dynamics as it had been proposed by other authors. He also proposes an overview of the evolution and disappearance of defects during thermal treatments. After a review of experiments based on the on-line Moessbauer effect, the author reports the study of recoil effects in pure metals (iron, hafnium), in alloys (Fe 1-x Al x , FeGe 2 , cubic, monoclinic and hexagonal FeGe), and in organic complexes (ferrous oxalate, different types of hafnium chelate, hafnium oxide). He finally discusses the electronic properties of different types of iron and hafnium chelate in solid phase [fr

  2. Grindability of cast Ti-Hf alloys.

    Science.gov (United States)

    Kikuchi, Masafumi; Takahashi, Masatoshi; Sato, Hideki; Okuno, Osamu; Nunn, Martha E; Okabe, Toru

    2006-04-01

    As part of our systematic studies characterizing the properties of titanium alloys, we investigated the grindability of a series of cast Ti-Hf alloys. Alloy buttons with hafnium concentrations up to 40 mass% were made using an argon-arc melting furnace. Each button was cast into a magnesia-based mold using a dental titanium casting machine; three specimens were made for each metal. Prior to testing, the hardened surface layer was removed. The specimens were ground at five different speeds for 1 min at 0.98 N using a carborundum wheel on an electric dental handpiece. Grindability was evaluated as the volume of metal removed per minute (grinding rate) and the volume ratio of metal removed compared to the wheel material lost (grinding ratio). The data were analyzed using ANOVA. A trend of increasing grindability was found with increasing amounts of hafnium, although there was no statistical difference in the grindability with increasing hafnium contents. We also found that hafnium may be used to harden or strengthen titanium without deteriorating the grindability.

  3. Estudo de associação entre força muscular e massa magra em mulheres idosas Estudio de la asociación entre fuerza muscular y masa magra en mujeres mayores Association between muscle strength and fat-free mass in older women

    Directory of Open Access Journals (Sweden)

    Ricardo Moreno Lima

    2012-12-01

    Full Text Available O objetivo do presente estudo foi verificar a associação entre a força muscular isocinética da musculatura extensora do joelho do membro dominante com a MM de diferentes segmentos corporais, em mulheres idosas. Um total de 258 idosas (66,58±5,6anos; 65,6±11,7kg; 1,53±0,07m foram submetidas à avaliação isocinética do pico de torque (PT e da MM (DXA. Correlações de Pearson foram examinadas entre os índices de MM dos braços, das pernas, do tronco, do corpo inteiro, da perna dominante (MMB, MMP, MMT, MMI, MMPD, respectivamente com o PT. O nível de significância foi de El objetivo de este estudio fue correlacionar la fuerza muscular de los extensores de la rodilla con la Masa Magra (MM en diferentes segmentos corporales en mujeres mayores. 258 mujeres mayores (66,58±5,6años; 65,6±11,7kg; 1,53±0,07m fueron someter a la evaluación del pico de torque (PT en el dinamómetro (Biodex y de la MM (DXA. Correlaciones de Pearson se realizó entre la MM de los brazos, piernas, tronco, el cuerpo entero, de la pierna dominante (MMB, MMPs, MMT, MMCI, MMPD, respectivamente con el PT. La MM de todas regiones examinadas presentaron correlación positiva y significante con los valores del PT (pThe purpose of the present study was to correlate knee extensors muscle strength with fat-free mass (FFM of different body sites in older women. Peak torque (PT from 258 women (66.58±5.6years; 65.6±11.7kg; 1.53±0.07m was assessed using an isokinetic dynamometer (Biodex and FFM was evaluated using dual-energy x-ray absorptiometry (DXA. Pearson correlations were performed between FFM from Arms, Legs, Thorax, Whole Body and Dominant Leg (FFMA, FFMLs, FFMT, FFMWB and FFMDL, respectively with PT. Significance level was set at α <0.05 for all comparisons. Positive and significant correlations were observed between FFM from all sites and isokinetic PT (p<0.001. However, it was stronger when the site of FFM analyzed was closer to the muscle responsible to

  4. The Fast-Casual Conundrum: Fast-Casual Restaurant Entrées Are Higher in Calories than Fast Food.

    Science.gov (United States)

    Schoffman, Danielle E; Davidson, Charis R; Hales, Sarah B; Crimarco, Anthony E; Dahl, Alicia A; Turner-McGrievy, Gabrielle M

    2016-10-01

    Frequently eating fast food has been associated with consuming a diet high in calories, and there is a public perception that fast-casual restaurants (eg, Chipotle) are healthier than traditional fast food (eg, McDonald's). However, research has not examined whether fast-food entrées and fast-casual entrées differ in calorie content. The purpose of this study was to determine whether the caloric content of entrées at fast-food restaurants differed from that found at fast-casual restaurants. This study was a cross-sectional analysis of secondary data. Calorie information from 2014 for lunch and dinner entrées for fast-food and fast-casual restaurants was downloaded from the MenuStat database. Mean calories per entrée between fast-food restaurants and fast-casual restaurants and the proportion of restaurant entrées that fell into different calorie ranges were assessed. A t test was conducted to test the hypothesis that there was no difference between the average calories per entrée at fast-food and fast-casual restaurants. To examine the difference in distribution of entrées in different calorie ranges between fast-food and fast-casual restaurants, χ(2) tests were used. There were 34 fast-food and 28 fast-casual restaurants included in the analysis (n=3,193 entrées). Fast-casual entrées had significantly more calories per entrée (760±301 kcal) than fast-food entrées (561±268; Prestaurants to determine whether the energy content or nutrient density of full meals (ie, entrées with sides and drinks) differs between fast-casual restaurants and fast-food restaurants. Calorie-conscious consumers should consider the calorie content of entrée items before purchase, regardless of restaurant type. Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  5. CORRELATIONS BETWEEN HOT CALCIUM CHLORIDE-EXTRACTED BORON AND CHEMICAL AND PHYSICAL ATTRIBUTES OF SOME BRAZILIAN SOILS CORRELAÇÕES ENTRE BORO SOLÚVEL EM CLORETO DE CÁLCIO 0,01 mol L-1 A QUENTE E ATRIBUTOS QUÍMICOS E FÍSICOS DE ALGUNS SOLOS BRASILEIROS

    Directory of Open Access Journals (Sweden)

    Luís Reynaldo Ferracciú Alleoni

    1999-01-01

    Full Text Available Relationship between soluble boron extracted with a hot CaCl2 0.01 mol L-1 solution and pH; organic carbon; exchangeable cations; cation exchange capacity (CEC; base saturation; total, free and amorphous iron and aluminum oxide contents; clay content; and specific surface area were performed for surface and subsurface samples of five soils. The soils were a Rhodic Hapludox, an Arenic Paleudalf and three Typic Hapludox, all representative soils of the State of São Paulo, Brazil. To quantify the relations between soluble boron and the different soil characteristics, simple linear correlations and multiple regressions, using a stepwise regression program, were performed. Hot-CaCl2 extractable boron (HCB was significantly correlated with clay content (r = 0.69*, specific surface area (r = 0.68*, CEC (r = 0.63* and total aluminum oxides (r = 0.70* in all five soils. In addition, there was a correlation between HCB and organic carbon (r = 0.75* in the four Oxisols. The correlation coefficient between the product (carbon x clay and soluble boron contents was also highly significant (r = 0.78**. Multiple regression analysis showed that total aluminum oxide, as well as exchangeable calcium and aluminum, were correlated with HCB, explaining 85% of the variation. The product (carbon x clay took into account the effect of textural gradient and showed high positive correlation with hot-CaCl2 0.01 mol L-1extractable boron.Teores de boro solúveis em CaCl2 0,01 mol L-1 a quente, de amostras superficiais e subsuperficiais de dois Latossolos argilosos, dois Latossolos de textura média e um Podzólico Vermelho-Amarelo do Estado de São Paulo, Brasil, foram correlacionados com alguns de seus atributos químicos e físicos. As correlações entre boro solúvel e superfície específica (r = 0,68*, argila (r = 0,69*, CTC (r = 0,63* e alumínio total (r = 0,70* dos cinco solos e com o teor de carbono orgânico dos quatro Latossolos (r = 0,75* foram estatisticamente

  6. Interactions entre muqueuse orale, salive et molécules de la flaveur

    OpenAIRE

    Ployon, Sarah

    2016-01-01

    Le rôle de la salive dans la perception sensorielle est de plus en plus reconnu, notamment par le biais des interactions physico-chimiques pouvant s’établir entre protéines salivaires et constituants alimentaires. Ce travail s’intéresse à la pellicule salivaire, la couche de protéines salivaires ancrées aux cellules épithéliales, et vise à caractériser les interactions pouvant s’établir d’une part entre ces protéines et épithélium oral, et d‘autre part entre ces protéines et les molécules de ...

  7. Correlation between the Doppler velocimetry findings of the uterine arteries during the first and second trimesters of pregnancy Correlação entre os achados doppplervelocimétricos das artérias uterinas no primeiro e segundo trimestres da gestação

    Directory of Open Access Journals (Sweden)

    Adolfo Wenjaw Liao

    2009-01-01

    Full Text Available OBJECTIVES: Evaluate the feasibility of transvaginal uterine artery Doppler examination in the first and second trimesters of pregnancy, establish reference ranges in a Brazilian population and examine the correlation between these Doppler findings. METHODS: Longitudinal prospective study at the antenatal clinic of a tertiary teaching hospital. Uterine artery Doppler examinations were carried out transvaginally at 11 to 14 weeks and 20 to 25 weeks of gestation. Uterine artery mean pulsatility index (PI distributions were determined and the presence or absence of an early diastolic notch was also noted. The degree of correlation between first and second trimester Doppler findings was examined. RESULTS: Three hundred and forty four women with live singleton pregnancies and normal outcome were first examined at a mean gestation of 12.7 weeks. The values corresponding to the 50th and 95th centiles of mean PI were 1.69 and 2.48. Bilateral notches were observed in 44% of cases and unilateral notches were present in 19%. Second trimester Doppler examinations were carried out at a mean gestation of 23.2 weeks and corresponding figures for the 50th and 95th centiles were 1.03 and 1.57. Bilateral notches were noted in 4.4% of the cases. First trimester impedance indices were significantly higher and positively correlated to second trimester findings (r = 0.42, pOBJETIVO: Avaliar a aplicabilidade de realizar exames dopplervelocimétricos endovaginais das artérias uterinas no primeiro e segundo trimestres da gestação, definir valores normais na população brasileira e examinar a correlação entre esses achados. MÉTODOS: Estudo prospectivo longitudinal conduzido em Hospital Universitário Terciário. Os exames dopplervelocimétricos das artérias uterinas foram realizados pela via endovaginal, entre 11 a 14 semanas e 20 a 25 semanas de gestação. Em cada período gestacional estudado, a distribuição dos valores dos índices de pulsatilidade (IP m

  8. PAPEL DE LA CONFIANZA en las relaciones entre organizaciones

    Directory of Open Access Journals (Sweden)

    Irene Juana Guillén Mondragón

    2006-07-01

    Full Text Available El objetivo del presente documento es analizar las definiciones y la importancia de la confianza para crear relaciones de cooperación entre organizaciones de naturaleza distinta. Se hace referencia a los modelos de organización dominantes para acercarnos a los nuevos mecanismos de regulación social propuestos por la sociología para tratar la organización, debido a que en el contexto actual las nuevas concepciones de la organización del trabajo han promovido en las organizaciones formas distintas de competir en el mercado. Procesos de cambio que obligan a las organizaciones a construir una nueva identidad y a renovar los contratos psicológicos con sus integrantes. La noción de confianza ha sido llevada del ámbito social al organizacional con la finalidad de lograr acuerdos entre organizaciones y al mismo tiempo lograr el compromiso de los integrantes de tales entidades. Para que estas puedan funcionar bajo este marco de transformaciones requieren de relaciones de colaboración regidas por la  confianza; relaciones que se dan en los niveles individual, dentro de la organización, entre organizaciones e institucionalmente. Los diferentes niveles de confianza están presentes en las relaciones que entablan los individuos, tanto dentro de la organización como en su entorno. Algunas de las reflexiones en torno a esta problemática nos llevan a pensar que el papel de la confianza es dinámico e incide en la transferencia y el intercambio de conocimientos, técnicas y procedimientos científicos, tecnologías, productos, capitales, entre otros. Además, las relaciones fundadas en la confianza requieren de la suspensión del propio interés, en beneficio de unaorientación colectiva (Mangematin y Thuderoz, 2003. Sin embargo, también se reconoce que con todo y la posibilidad que el hombre tiene de deliberar y de generar confianza, es evidente que entre los hombres prevalecen tanto la confianza calculada como los deseos de altruismo para entrar

  9. Causalidade entre as principais bolsas de valores do mundo

    Directory of Open Access Journals (Sweden)

    Hiron Pereira Farias

    2010-04-01

    Full Text Available O objetivo deste trabalho foi analisar os mercados dos países emergentes que fazem parte do Bric, com exceção da Índia, buscando mostrar como os mercados do Brasil, da Rússia e China se comportam entre si e em relação ao mercado dos Estados Unidos. Analisou-se também como alguns países desenvolvidos do grupo G8, Estados Unidos, Reino Unido e Japão, se comportam. Em cada análise, ajustou-se um modelo VAR e buscou-se verificar o grau de dependência dentro e entre cada grupo, utilizando teste de causalidade de Granger, critérios de seleção de modelos, função resposta a impulso e decomposição da variância do erro de previsão. Nas análises realizadas, os mercados brasileiro e americano mostraram forte influência sobre os demais mercados, e, na análise entre os grupos, consideraram-se o mercado dos Estados Unidos do grupo ERJ e todos os mercados emergentes do grupo BRC. O mercado americano mostrou forte influência sobre os outros mercados.

  10. Factores de riesgo que condicionan la conducta machista entre adolescentes.

    OpenAIRE

    Sánchez Alonso, Isabel

    2016-01-01

    Este trabajo sobre los factores de riesgo que condicionan la violencia machista entre adolescentes, recoge las principales argumentaciones que explican el origen de la desigualdad entre hombres y mujeres y de cómo la diferencia biológica ha incidido en la división del trabajo según el sexo y en las funciones y roles que debe desempeñar cada uno. A continuación señala los principales factores de riesgo que condicionan la violencia machista en las primeras relaciones am...

  11. Correlação entre testes de vigor em sementes de maxixe Correlation among vigor tests on gherkin seeds

    Directory of Open Access Journals (Sweden)

    Salvador Barros Torres

    1999-06-01

    Full Text Available O objetivo deste trabalho foi comparar a eficiência de diferentes testes para determinação da qualidade fisiológica de sementes de maxixe (Cucumis anguria L., visando melhorar sua utilização como testes de qualidade e verificar suas relações com a emergência de plântulas em campo. Foram avaliadas sementes de sete lotes, pelos testes de germinação, primeira contagem de germinação, condutividade elétrica a 4 e 24 horas, envelhecimento acelerado, deterioração controlada, teste de frio sem solo e emergência de plântulas em campo. O trabalho foi desenvolvido no Laboratório de Análise de Sementes e em um campo experimental da Embrapa-CPATSA, em Petrolina, PE, no período de janeiro a maio de 1996. Nos testes de laboratório, o delineamento experimental foi inteiramente casualizado, e nos testes de campo foi usado o delineamento em blocos casualizados - ambos com quatro repetições de cinqüenta sementes, sendo as médias comparadas pelo teste de Tukey a 1% de probabilidade. Os testes de germinação e vigor foram eficientes para detectar diferenças de qualidade fisiológica entre lotes de sementes de maxixe. Os testes de deterioração controlada e de frio sem solo foram mais consistentes na separação dos lotes em diferentes níveis de vigor, e ao mesmo tempo apresentaram os maiores níveis de correlação com a emergência de plântulas em campo.This work was carried out with the objective of comparing the efficiency of different tests in the physiological quality of gherkin seeds (Cucumis anguria L., looking for information for a better utilization of these quality control tests, as well as verifying their relation at field emergency. Seven lots of gherkin seeds were evaluated by the germination test, first count, electrical conductivity at 4 and 24 hours, accelerated aging, controlled damage, cold without soil, and field emergency. The trials were carried out at the Seed Lab and at an experimental field of Embrapa

  12. Bose-Einstein correlations between hard photons produced in heavy ions collisions; Correlations Bose-Einstein entre photons durs produits dans les collisions d`ions lourds

    Energy Technology Data Exchange (ETDEWEB)

    Marques Moreno, F M

    1994-06-01

    Heavy-ion collisions offer the unique possibility to create in the laboratory nuclear matter far from equilibrium. The electromagnetic probe constituted by hard photons and the Bose-Einstein correlations were used to study the properties of such a matter (size, density, temperature...). It is shown how the formalism has evolved from Young experiments to heavy-ion collisions experiments. The experiments performed with the photon multidetector TAPS at Ganil are described. The systems studied are: {sup 86}KR + {sup nat}Ni at 60.0 A.MeV, and {sup 181}Ta + {sup 197}Au at 39.5 A.MeV. Results are presented concerning the production of gamma, pi{sup 0}, e{sup +-} and {gamma}{gamma} correlation. The results are interpreted with the help of static and dynamic calculations describing hard photon production in heavy ion collisions. For the first time in Nuclear Physics, the existence of the Bose-Einstein effect for photons in the range of gamma is demonstrated, and the existence of two different photon sources is postulated, reflecting the density oscillations taking place in the nuclear matter created in heavy-ion collisions. (from author) 55 figs., 22 tabs., 76 refs.

  13. Entre monos y centauros

    Directory of Open Access Journals (Sweden)

    Serge Gruzinski

    2005-02-01

    Full Text Available    ¿Qué relación puede existir entre Ovidio, Tiziano y unos tlacuilo indios de la sierra otomí ? ¿Qué tienen en comun  el pintor mas famoso del siglo XVI , el veneciano Tiziano (+ 1576,  un poeta latino del primer siglo despues de Cristo, Publio Ovidio Nasón (-43/17 ,  y unos artistas indígenas anónimos del pueblo otomi de Ixmiquilpan?   Aunque la reunión de estos tres nombres parezca extraña y sorprendente, los hilos que los unen no son nada anecdóticos.  Permiten entender mejor la manera...

  14. Relación entre la lateralidad y los aprendizajes escolares

    Directory of Open Access Journals (Sweden)

    M.ª Carmen Mayolas Pi

    2010-09-01

    Full Text Available Muchos son los autores que relacionan los problemas de aprendizaje de un niño con su lateralidad, achacando a la lateralidad contrariada, cruzada o no definida los problemas en la adquisición, entre otras, de habilidades lecto-escritoras. En el presente trabajo hemos pasado un test de lateralidad a 170 niños de entre 6 y 7 años (primero y segundo de primaria con pruebas de miembro superior, miembro inferior y ojo, así como de discriminación de derecha-izquierda y de orientación espacial. A su vez, los profesores tutores han valorado varios ítems del aprendizaje escolar de los niños, con cuestiones sobre su comprensión lectora, su razonamiento matemático y su atención en clase, entre otras. Según nuestros resultados, los niños con lateralidad homogénea diestra son los que obtienen mejores valoraciones en todos los ítems de aprendizaje con respecto a los homogéneos zurdos, los cruzados y los no confirmados, siendo los pocos casos que tenemos de homogéneos zurdos (un 3% de la muestra los que tienen peores valoraciones. Además, los niños que discriminan entre derecha e izquierda también tienen mejor sus aprendizajes con respecto a los que no lo hacen, así como los que se orientan bien en el espacio con respecto a los que se orientan mal.

  15. Interações medicamentosas potenciais entre medicamentos psicotrópicos dispensados

    Directory of Open Access Journals (Sweden)

    Eloise Balen

    Full Text Available RESUMO Objetivo Estimar a frequência e caracterizar as interações medicamentosas potenciais entre fármacos psicotrópicos sujeitos a controle especial pela portaria 344/98 da Agência Nacional de Vigilância Sanitária (Anvisa, os quais foram prescritos e dispensados em uma farmácia pública do Município de Cascavel, Paraná. Métodos Estudo retrospectivo com desenho seccional foi realizado em uma Farmácia Pública Municipal. A amostra foi composta por prescrições de medicamentos sujeitos a controle especial, dispensados entre primeiro de julho a 31 de agosto de 2010. As prescrições retidas na farmácia foram analisadas retrospectivamente e as informações, coletadas. As interações medicamentosas potenciais foram identificadas em 824 prescrições. Resultados As prescrições eram na maioria para pacientes do sexo feminino e com idade entre 19 e 59 anos. Em relação à especialidade do prescritor, 30,6% foram prescritas por psiquiatra. Em 77,9% das prescrições identificou-se pelo menos uma interação medicamentosa potencial. Foram descritas 54 diferentes interações medicamentosas potenciais, sendo 34 graves e 20 moderadas. Encontrou-se uma correlação linear entre medicamentos prescritos e interações medicamentosas potenciais (p valor < 0,001. Conclusão O presente estudo identificou uma alta frequência de interações medicamentosas potenciais envolvendo fármacos de controle especial e uma associação positiva entre o número de fármacos prescritos com a maior frequência dessas interações.

  16. Sinergias entre Luxemburgo, ACNUR y Skype

    OpenAIRE

    Bertout, Antoine; Bourcy, Marc de; Faisal, Mohammad

    2011-01-01

    Una reciente asociación estratégica entre ACNUR, el Gobierno de Luxemburgo y el proveedor de software para comunicaciones Skype permite al personal de ACNUR en zonas de condiciones de vida difíciles mantenerse en contacto con sus familiares y amigos. Los socios evalúan de qué forma podría adaptarse la tecnología para otras organizaciones humanitarias.

  17. Continuidade entre estética e investigação na teoria da arte deweyana: a educação entre arte e ciência, valor e método, ou entre o ideal e o real

    OpenAIRE

    Ana Daniele de Godoy Dorsa

    2013-01-01

    A presente pesquisa, de natureza teórico-filosófica, argumenta descritivamente a teoria estética do filósofo americano John Dewey, em função do seu chamado \\"princípio de continuidade\\", próprio do sistema filosófico deweyano como um todo. Nessa empreitada, privilegiou-se o recorte da continuidade entre o estético e o científico, ou entre valor e investigação enquanto característica essencial de tal teoria estética. Na observação dos pressupostos filosóficos gerais do filósofo, verificou-se q...

  18. Las relaciones entre España y Japón

    OpenAIRE

    Jensana, Amadeo

    2013-01-01

    Si bien España y Japón son dos países separados por más de 10.000 kilómetros existe una importante afinidad cultural entre ambos pueblos. Los japoneses admiran muchas de las manifestaciones culturales españolas, entre las que destacan la arquitectura (especialmente el Modernismo catalán), el flamenco, la gastronomía o el deporte (hay numerosos seguidores de la Liga Profesional de Fútbol). Por su parte, los españoles son plenamente conscientes del nivel tecnológico de las grandes corporacio...

  19. ESCREVER ENTRE AS LÍNGUAS: TRADUÇÃO E GÊNERO EM NANCY HUSTON

    OpenAIRE

    WILHELM, Jane Elisabeth; COSTA, Pâmela Berton; DEÂNGELI, Maria Angélica

    2017-01-01

    O entre duas línguas da auto-tradução em Nancy Huston subverte as relações hierárquicas entre o original e a tradução, ou a oposição entre língua materna e língua estrangeira, e nos convida assim a nos interrogarmos sobre nossas práticas e representações de escrita e de tradução. Buscamos compreender em que medida a escrita entre o francês e o inglês de Nancy Huston questiona não somente as categorias tradicionais de tradução, mas também o gênero como construção social. A história da tradução...

  20. Radioisotopic heat source

    Science.gov (United States)

    Jones, G.J.; Selle, J.E.; Teaney, P.E.

    1975-09-30

    Disclosed is a radioisotopic heat source and method for a long life electrical generator. The source includes plutonium dioxide shards and yttrium or hafnium in a container of tantalum-tungsten-hafnium alloy, all being in a nickel alloy outer container, and subjected to heat treatment of from about 1570$sup 0$F to about 1720$sup 0$F for about one h. (auth)

  1. Entre-sons, entre-mundos, entre-idades: ações dialógicas, cultura adolescente e educação musical

    OpenAIRE

    Vertamatti, Leila Rosa Gonçalves [UNESP

    2012-01-01

    O presente trabalho tem como ponto central a reflexão a respeito da prática da Educação Musical de jovens entre 11 e 14 anos, do Colégio São José de São Bernardo do Campo, a partir de uma proposta que dialogue com o universo do adolescente, a invenção, a percepção do ambiente acústico, visual, social e cultural e o contexto escolar. A principal questão da investigação é a discussão de processos de elaboração de ações musicais com base em um conceito de prática que leve em conta a distância ex...

  2. High-spin nuclear target of 178m2Hf: creation and nuclear reaction studies

    International Nuclear Information System (INIS)

    Oganessyan, Yu.Ts.; Karamyan, S.A.; Gangrskij, Yu.P.

    1993-01-01

    A long-lived (31 years) four-quasiparticle isomer 178m 2 Hf(I,K π =16,16 + ) was produced in microweight quantities using the nuclear reaction 176 Yb( 4 He, 2n). Methods of precision chemistry and mass-separation for the purification of the produced Hf material have been developed. Thin targets of isomeric hafnium-178 on carbon backings were prepared and used in experiments on a neutron, proton and deuteron beams. First results on nuclear reactions on a high-spin exotic target were obtained. Experiments on electromagnetic interactions of the isomeric hafnium using methods of the collinear laser spectroscopy as well as of the nuclear orientation of hafnium implanted into a crystalline media were started. 11 refs.; 11 figs.; 2 tabs

  3. New type of colour reactions of o,o'-dihydroxyazo compounds

    International Nuclear Information System (INIS)

    Dedkov, Yu.M.; Podvigina, T.I.

    1977-01-01

    It is shown that in the system: zirconium (hafnium)-picramine-epsilon (PE)-ethylrhodamine S (ERS), a heteroligand complex is formed, with an excess of the organic reagents, having the following ratio of components: Zr(Hf):PE:ERS=1:2:5. The molecules of ERS substitute the protons of free OH groups in binary complexes of zirconium (hafnium) with PE, while the excess molecules of ERS are added associatively. The resulting complex is floated off, the flotation product is dissolved in acetone, and its optical density is measured. The true molar extinction coefficient of the complex is equal to 6x10 5 , while the apparent one equals 3.2x10 5 . It is possible to determine submicroamounts of zirconium (hafnium) with preminary Ti and Nb masking

  4. Correlational study between sorption and goo apparent organoclays; Estudo correlacional entre sorcao e viscosidade aparente em argilas organofilicas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, D.L.; Silva, M.R.O.; Ferreira, H.S.; Brasileiro, C.T., E-mail: darciely_lin@hotmail.com, E-mail: marcusraffael@outlook.com, E-mail: hebersivini@gmail.com, E-mail: camilabrasileiro@globo.com [Universidade Federal da Paraiba (UFPB), PB (Brazil)

    2016-07-01

    The sorption of surfactants in bentonite clay can occur through the mechanism of adsorption and absorption, this being a very supple phenomenon according clay and surfactant utilized. Thus the more surfactant sorbed at the organoclay it becomes, and can be used in various applications, including in oil drilling fluid. This study aimed to correlate the sorption of surfactants with the rheological properties of non-aqueous fluids (oil base). In organophilization process was used Bentongel clay which had its concentration varied from 3.16 to 7.16% by weight of clay. It was used to organophilization an ionic surfactant Praepagem WB with 75% of active matter, where its concentration ranged from 127-181 mEq. After organophilizated the clays were filtered, dried in an oven for 48 hours and passed in ABNT sieve No. 200, to be so characterized. Sorption was calculated from mathematical equations. Non-aqueous fluids were prepared according to standard Petrobras (EP-1EP-00023A) for rheological testing. Correlating the sorption of surfactant, and the rheological properties of non-aqueous fluid, obtained satisfactory results where observed through the scatter plots there is a strong correlation between the variables sorption and apparent viscosity, it should also be noted that the viscosity is a variable which increases with an increase in sorption, confirming that the surfactant concentration influences the viscosity. (author)

  5. Responsabilidad extracontractual y contractual: barrera entre ambas

    Directory of Open Access Journals (Sweden)

    González Hernández, Rut

    2013-01-01

    Full Text Available La finalidad que persigue el sistema de responsabilidad civiles el resarcimiento del daño causado con independencia de que proceda la responsabilidad contractual o la extracontractual, coexistiendo ambas en nuestro ordenamiento jurídico y resultando en ocasiones complicado discernir la frontera entre una y otra.

  6. Comparação de biomarcadores inflamatórios entre pacientes diabéticos e não-diabéticos com angina instável Comparación de biomarcadores inflamatorios entre pacientes diabéticos y no-diabéticos con angina inestable Comparison of inflammatory biomarkers between diabetic and non-diabetic patients with unstable angina

    Directory of Open Access Journals (Sweden)

    Marçal de Oliveira Huoya

    2009-04-01

    -diabéticos con AI, lo que indica que ese cuadro clínico puede equilibrar la actividad inflamatoria entre los dos grupos y aumentar la concentración de marcadores inflamatorios de fase aguda, independientemente del estado metabólico.BACKGROUND: Studies comparing inflammatory activity between diabetic and non-diabetic individuals with acute coronary syndrome are scarce, and none including only patients with unstable angina (UA has been published to date. OBJECTIVE: We compared serum C-reactive protein (CRP, and interleukin-6(IL-6 between diabetic and non-diabetic patients with unstable angina (UA to determine if difference in inflammatory activity is responsible for a worse prognosis in diabetic patients. We also evaluated the correlation between inflammatory markers and the metabolic profile in diabetic patients and the correlation between inflammatory response and in-hospital outcomes: death, acute myocardial infarction, congestive heart failure, and length of stay in hospital. METHODS: A prospective cohort study of 90 consecutive patients admitted to a chest pain unit with UA and divided into two groups, diabetic and non-diabetic. Serum CRP, IL-6, metabolic profile and leukocyte count were measured at hospital arrival. RESULTS: Forty-two patients (47% were diabetic (age 62±9 vs. 48 (53% non-diabetic (age 63±12. No differences between median C-reactive protein (1.78 vs. 2.23mg/l,p=0.74 and interleukin-6 (0 vs. 0pg/ml,p=0.31 were found between the two groups. There was a positive correlation between CRP and total cholesterol (rs = 0.21,p = 0.05, CRP and LDL-cholesterol (rs=0.22,p=0.04 and between CRP and leukocyte count (rs = 0.32, p = 0.02 in both groups. No associations were found between inflammatory markers and in-hospital outcomes. CONCLUSION: We found no difference in inflammatory activity between diabetic and non-diabetic patients with UA, suggesting that this clinical condition may result in balanced inflammatory activity between the two groups and increase acute

  7. Evolution of E 2 transition strength in deformed hafnium isotopes from new measurements on 172Hf,174Hf, and 176Hf

    Science.gov (United States)

    Rudigier, M.; Nomura, K.; Dannhoff, M.; Gerst, R.-B.; Jolie, J.; Saed-Samii, N.; Stegemann, S.; Régis, J.-M.; Robledo, L. M.; Rodríguez-Guzmán, R.; Blazhev, A.; Fransen, Ch.; Warr, N.; Zell, K. O.

    2015-04-01

    Background: The available data for E 2 transition strengths in the region between neutron-deficient hafnium and platinum isotopes are far from complete. More and precise data are needed to enhance the picture of structure evolution in this region and to test state-of-the-art nuclear models. In a simple model, the maximum collectivity is expected at the middle of the major shell. However, for actual nuclei, particularly in heavy-mass regions, which should be highly complex, this picture may no longer be the case, and one should use a more realistic nuclear-structure model. We address this point by studying the spectroscopy of Hf as a representative case. Purpose: We remeasure the 21+ half-lives of 172,174,176Hf, for which there is some disagreement in the literature. The main goal is to measure, for the first time, the half-lives of higher-lying states of the rotational band. The new results are compared to a theoretical calculation for absolute transition strengths. Method: The half-lives were measured using γ -γ and conversion-electron-γ delayed coincidences with the fast timing method. For the determination of half-lives in the picosecond region, the generalized centroid difference method was applied. For the theoretical calculation of the spectroscopic properties, the interacting boson model is employed, whose Hamiltonian is determined based on microscopic energy-density functional calculations. Results: The measured 21+ half-lives disagree with results from earlier γ -γ fast timing measurements, but are in agreement with data from Coulomb excitation experiments and other methods. Half-lives of the 41+ and 61+ states were measured, as well as a lower limit for the 81+ states. Conclusions: This work shows the importance of a mass-dependent effective boson charge in the interacting boson model for the description of E 2 transition rates in chains of nuclei. It encourages further studies of the microscopic origin of this mass dependence. New experimental

  8. Theoretical and experimental study of heat transfers and pressure drops along surfaces fitted with herring-bone fins: correlation between geometric and aero thermal parameters; Etudes theorique et experimentale du transfert de chaleur et des pertes de charge de surfaces munies d'ailettes disposees en chevron - correlation entre parametres geometriques et aerothermiques

    Energy Technology Data Exchange (ETDEWEB)

    Pelce, J; Malherbe, J; Pierre, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Principal results are given of experimental research which has been carried out on the flow of a fluid along a surface fitted with herringbone fins. Aero-thermal tests have been effected on a large number of these surfaces whose geometrical parameters have been made to vary systematically. In particular, work on a large scale model has made it possible to analyse the mechanisms of heat transfer and of pressure drops. On this basis a theoretical study has led to the establishment of a correlation between the geometric configuration and the aero-thermal performances of these surfaces. Experimental results are in good agreement with the theoretical relationships. An expression has thus been derived applicable to this type of herring-boned surface in a wide zone. (authors) [French] L'ecoulement d'un fluide au voisinage d'une surface munie d'ailettes disposees en chevron a fait l'objet de recherches experimentales dont on a rappele les principaux resultats. Des essais aerothermiques ont ete effectues sur un grand nombre de ces surfaces dont a fait varier les parametres geometriques de facon systematique. En particulier, des etudes sur une maquette a grande echelle ont permis d'analyser les mecanismes de transfert de chaleur et de perte de charge. Sur ces bases, une etude theorique a conduit a des correlations entre la geometrie et les performances aerothermiques de ces surfaces. Les resultats experimentaux sont en bon accord avec les relations theoriques. On possede ainsi une formulation pour ce type de surface ailettee valable dans un domaine etendu. (auteurs)

  9. Correlación ecológica entre consumo de bebidas alcohólicas y mortalidad por cirrosis hepática en México Ecological correlation between alcohol use and cirrhosis mortality in Mexico

    OpenAIRE

    JOSÉ NARRO-ROBLES; JESÚS HECTOR GUTIÉRREZ-AVILA

    1997-01-01

    Objetivo. Determinar la correlación entre consumo de bebidas alcohólicas y mortalidad por cirrosis hepática. Material y métodos. Se efectuó un análisis de correlación ecológica entre el conjunto de variables que integran el patrón de consumo de bebidas alcohólicas investigadas en la Encuesta Nacional de Adicciones en 1993 y la mortalidad por cirrosis hepática, en el periodo 1971-1993 en las ocho regiones en que fue dividido el país. Para determinar el nivel de correlación se utilizaron los co...

  10. Investigation of hyperfine interactions in hafnium compounds with F{sup 1-}, OH{sup 1-}, and EDTA ligands by perturbed {gamma}-{gamma} angular correlation

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Antonio A.; Silva, Andreia dos S.; Lapolli, Andre L.; Carbonari, Artur W.; Saxena, Rajendra N., E-mail: alapolli@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    In this study the hyperfine parameters, including the dynamical nature, Perturbed Angular Correlation (PAC) spectroscopy was used to measure the hyperfine parameters in molecules of ligand compounds in solutions. The measurements were carried out at 295 K and 77 K using {sup 181}Hf {yields}{sup 181}Ta, as probe nuclei. Samples were prepared by adding a small volume of radioactive solution containing the probe nuclei in aqueous solution, buffer solution and ethylenediaminetetraacetic acid (EDTA) used as a ligand with pH between 4 and 5 which correspond to the pH of the saturated EDTA solution and in buffer solution with pH between 9 and 10. The results made possible to understand the impact of each method for PAC measurements. Finally a comparative analysis for the several methods of inserting of the probe nuclei in the sample was made, considering chemical and nuclear aspects. The lack of measurements in this kind of samples justifies the importance of the obtained results. (author)

  11. La Vocación entre los Aspirantes a Maestro

    Directory of Open Access Journals (Sweden)

    Encarnación Sánchez Lissen

    2003-01-01

    Full Text Available El contenido que ofrecemos en este artículo hace referencia a la dimensión vocacional de los aspirantes a maestro. Tradicionalmente, la enseñanza se ha considerado como una profesión genuinamente vocacional; una circunstancia que, sin embargo, no siempre le ha favorecido. En estos momentos, a pesar de las dificultades que rodean la tarea docente, existe un alto número de estudian-tes que optan por la enseñanza y acceden a las Escuelas de Magisterio. Real-mente, nos podríamos preguntar si el docente -nace o se hace- vocacional hacia esta actividad profesional. Aportamos para ello, los datos de una investigación realizada entre estu-diantes de la Universidad de Sevilla, donde se viene a demostrar por un lado que, muchos eligieron la carrera sin tener un verdadero interés por ella; y por otro, que las Escuelas de Magisterio son en muchos casos, un motor esencial para llegar a despertar o, a descubrir entre los estudiantes, su verdadero interés e inclinación por la enseñanza. Posiblemente, desarrollar actitudes vocaciona-les entre tos aspirantes a maestro es, también, una labor implícita de la Forma-ción Inicial de Maestros

  12. RELACIÓN ENTRE CONDUCTA PARENTAL Y ADHERENCIA AL TRATAMIENTO EN DIABETES INFANTIL.

    Directory of Open Access Journals (Sweden)

    Rochy Vargas

    2008-07-01

    Full Text Available En este artículo, enmarcado en la psicología de la salud, se pretende identificar la relación que existe entre la conducta parental y la adherencia al tratamiento a partir de un diseño no-experimental de tipo transversal descriptivo correlacional, en una muestra de niños con diabetes tipo I, entre 8 y 11 años de edad, con un tiempo desde el diagnóstico de entre uno y tres años. Los resultados analizados señalan la relación que existe entre los comportamientos que engloba la variable de conducta parental y adherencia al tratamiento, pudiendo incluso diferenciar aquellos comportamientos más representativos para cada categoría; así por ejemplo, se encontró que la comunicaciónafectiva es el comportamiento parental que más está correlacionado con las conductas de adhesión. Con respecto a las conductas de adhesión al tratamiento, la dieta fue la conducta de este tipo que más se correlacionó con comportamientos parentales.

  13. Dos años entre los indios

    Directory of Open Access Journals (Sweden)

    Ardila Ardila Olga Felisa

    1996-06-01

    Full Text Available

    La obra constituye la traducción del alemán publicada originalmente en dos volúmenes por E. Wasmuth en Berlín en 1909. En 1967 la Akademische Druck-u Verlagsanstalt en Graz (Austria publicó la segunda edición de la obra original, sobre la cual se trabajó la presente versión en español. La traducción estuvo a cargo de la antropóloga María Mercedes Ortiz. Koch-Grünberg se dedicó al estudio de la filología clásica pero con el tiempo se fue interesando cada vez más por el estudio de los pueblos autóctonos de Suramérica. En 1903 realizó su primera expedición a partir del noroeste brasilero hasta Colombia, en la región comprendida entre el alto río Negro y el Yapurá, área muy poco explorada hasta el momento. La obra Dos años entre los indios resume los resultados básicos de esta expedición. El autor alemán presenta el relato de sus cuatro viajes e ilustra con un mapa la ruta de su expedición a partir del Amazonas. Además del noroeste brasilero, el autor recorre un área importante del territorio colombiano, especialmente la zona del actual departamento del Vaupés. El libro está escrito en forma de un diario de viaje en el que se destacan sus observaciones etnográficas y lingüísticas, especialmente en lo que respecta a la cultura material, el ritual, el arte, las diferentes lenguas nativas habladas en la región y las relaciones de afinidad existentes entre dichas lenguas.

  14. Alinhamento estratégico entre empresas fabricantes de equipamentos e alimentos

    Directory of Open Access Journals (Sweden)

    Roberto Giro Moori

    2009-08-01

    Full Text Available Este trabalho tem por objetivo verificar o alinhamento das prioridades competitivas entre empresas compradoras e usuárias de máquinas e equipamentos para a fabricação de produtos alimentícios e seus fornecedores industriais. Está fundamentado em uma pesquisa exploratória descritiva em que se aplicou um questionário estruturado junto a gestores das áreas relacionadas a compras, vendas e produção das empresas. Foram obtidas 77 respostas de gestores de empresas fabricantes de alimentos e 55 de fabricantes de equipamentos. Os dados, submetidos à estatística descritiva e à correlação bivariada não paramétrica, revelaram que: a no âmbito do relacionamento entre compradores e vendedores de máquinas e equipamentos, o fator qualidade foi a prioridade competitiva alinhada entre eles; b no âmbito de empresas usuárias de máquinas e equipamentos, houve evidência de trade-off entre as variáveis reduzir estoques e velocidade de entrega rápida. Essas revelações permitiram concluir que: a a qualidade é um fator de alinhamento externo e interno; b o trade-off é usado como um instrumento para o alinhamento das prioridades competitivas no ambiente interno das empresas compradoras e usuárias de máquinas e equipamentos.

  15. Correlation between haplotypes for k - caseine and lactic production characteristics in holstein cattle Correlación entre haplotipos para la k-caseína y características de producción láctea en bovinos holstein

    Directory of Open Access Journals (Sweden)

    Estrada L.

    1999-12-01

    Full Text Available Protein levels and specifically casein are important in the industrial processes of milk, especially in clotting and clot formation. Characterization of genotype frequencies is important to determine the genetic value of the animals. This experiment was carried out to determine the genotype frequencies and to establish the correlation between haplotypes and production phenotypes. Milk and blood samples were taken from 54 first parity Holstein heifers from farms in the Sabana de Bogotá (2000-3000 meters above sea level;12-18°C. Milk samples were analyzed for protein, casein, fat and lactose percent, whereas the blood was used to genotype the animals for the k-casein gene (AA, AB and BB. Also, data was taken from the Dairy Herd Improvement Program of the Holstein Association of Colombia for the 305 day 2X milk production. The data were used to determine the allelic and genotypic frequency of the k-casein gene and the correlation between the haplotypes and protein content, casein percent and 305 day 2X milk production projection. The genotype frequency was 57.41% for haplotype AA, 37.04% for haplotype AB and 5.55% for haplotype BB. The allelic frequency was 75.93% for allele A and 24.07% for allele B. There was a high significant correlation between the haplotypes and the protein percent in the milk (R>.975 being the BB haplotype superior to the AB and AA haplotypes. On the other hand, there was no significant correlation between the haplotypes and the casein percent nor the 305 day 2x milk production projection, even though the BB haplotype always showed higher valúes than the others.Los niveles de proteínas y específicamente de caseínas de interés en los procesos industriales de la leche especialmente en la coagulación y cantidad de cuajo. La caracterización molecular y establecimiento de las frecuencias genotípicas, que determinan cualidades de la leche, son por lo tanto importantes en predeterminar el valor genético de los animales

  16. A relação entre polifarmácia, complicações crônicas e depressão em portadores de Diabetes Mellitus Tipo 2 Relación entre polifarmacia, complicaciones crónicas y depresión en portadores de Diabetes Mellitus Tipo 2 The relationship between polipharmacy, chronic complications and depression in individuals with Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Alexandra Bulgarelli do Nascimento

    2010-03-01

    medicamentos/día o más; todos hicieron como mínimo tres tomas diarias, el 60% presentaba entre 1 y 3 complicaciones de la DM2 y el 22,5% presentaba 3 o más. La correlación entre los indicadores de depresión (IDB y CORT y el número de medicamentos y de complicaciones de la DM2 no fue estadísticamente significativa. Sin embargo, hubo correlación positiva entre CORT y la cantidad de tomas diarias de medicamentos (Spearman, r=0.319, p=0.019.The objectives of this study were: to characterize the polipharmacy in subjects with Type 2 Diabetes Mellitus (DM2 and to verify the correlation between polipharmacy and number of medications for DM2 complications with depression indicators (Beck Depression Inventory (BDI and urinary cortisol (CORT levels. A sample composed of 40 patients with DM2 from the Diabetes League of HCFM-USP was analyzed for depression indicators (CORT and BDI in addition to evaluation for polipharmacy and number of DM2 complications. The results showed oral hypoglycemic agents, insulins, antihypertensives, diuretics, lipid-lowering drugs and thrombolytics are the most frequent medications used. In this sample, 75% used from 5 to 8 medicines daily and 12.5% used more than eight medicines/day; all of them used to take each medication at least 3 times daily. Between 1 and 3 DM2 complications were observed in 60% of the individuals and 22.5% showed more than 3 DM2 complications. No significant correlations were observed between depression indicators (BDI and CORT, number of medications and DM2 complications. However, positive correlation was observed between CORT and daily frequency of medication (Spearman, r=0.319, p=0.019.

  17. Soutien aux collaborations entre pairs de l'Initiative Think tank et du ...

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

    L'Initiative Think tank (ITT) et le Think Tank Fund (TTF) s'associent pour soutenir des collaborations entre pairs entre les think tanks établis dans les régions où oeuvrent l'ITT (Afrique, Amérique latine et Asie du Sud) et le TTF (Europe centrale, Europe de l'Est et ancienne Union soviétique). Ce soutien a pour objectif de ...

  18. Vocabulário expressivo e consciência fonológica: correlações destas variáveis em crianças com desvio fonológico Expressive vocabulary and phonological awareness: correlations in children with phonological disorders

    Directory of Open Access Journals (Sweden)

    Tassiana Isabel Kaminski

    2011-06-01

    Full Text Available OBJETIVO: Investigar a correlação entre o desempenho de crianças com desvio fonológico em vocabulário expressivo e consciência fonológica e analisar a influência da idade. MÉTODOS: Contou-se com amostra de 24 crianças entre 5 e 7 anos, diagnosticadas com desvio fonológico e divididas em três grupos, de acordo com a faixa etária. Os sujeitos realizaram foram avaliados com relação às habilidades de consciência fonológica e vocabulário expressivo. Os dados dos grupos receberam análise estatística para verificar a correlação entre os desempenhos dos dois testes e comparar as variáveis numéricas entre as faixas etárias. RESULTADOS: No grupo de 5 anos, observou-se 18 correlações significativas entre as subtarefas em consciência fonológica e os campos de vocabulário expressivo. Destas, 17 foram positivas e uma negativa. Na idade de 6 anos, verificou-se dez correlações, nove foram positivas e uma negativa. No grupo de 7 anos, 11 correlações foram observadas, das quais seis foram negativas e cinco positivas. Ao analisar as idades, em ambos os testes, maiores escores foram obtidos pelos sujeitos com maior idade. CONCLUSÃO: Houve correlação entre algumas habilidades de consciência fonológica e o vocabulário expressivo dos sujeitos deste estudo, nas diferentes idades. O desempenho em ambas as provas melhorou com o aumento da idade.PURPOSE: To investigate the correlation between the performance of children with phonological disorder in tests of expressive vocabulary and phonological awareness, and to analyze the influence of age. METHODS: Participants were 24 children between 5 and 7 years old, diagnosed with phonological disorder and divided into three groups according to age range. These subjects were assessed in their phonological awareness and expressive vocabulary abilities. Data from the groups were statistically analyzed in order to verify the correlation between the performances on both tests, and to compare

  19. "Cy Twombly: Intérprete de dos mundos" [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo

    OpenAIRE

    Gras Cruz, Irene

    2017-01-01

    Esta tesis “Cy Twombly: Intérprete de dos mundos” [Un artista entre Estados Unidos y Europa, entre lo clásico y lo contemporáneo] pretende dar a conocer al artista norteamericano Cy Twombly (1928-2011) en nuestro país y destacar la importancia que tiene dentro del panorama artístico como figura clave en un momento de efervescencia —artística y creativa— americana en el que a diferencia de sus coetáneos prefirió emigrar a Europa, concretamente a Italia. Mientras todos se trasladaban a la nueva...

  20. Acciones y habilidades. Algunas discrepancias entre psicólogos y didactas

    Directory of Open Access Journals (Sweden)

    Carlos Ezequiel Pino-Pupo

    2012-01-01

    Full Text Available Abordó puntos de vista discrepantes entre representantes de algunas escuelas de Psicología y de Didáctica cubanas. Durante varios años de investigación en torno a la problemática de la formación de habilidades, se han encontrado posiciones teóricas, muy variadas y son diversos los criterios acerca de la movilidad entre las acciones y las operaciones y en torno a la automatización de unas u otras. Se analiza la equivalencia entre términos de la Didáctica, la Psicología y la Metodología con una propuesta nueva. La intencionalidad del artículo radica en que a partir de las posiciones teóricas asumidas, puede haber una reconsideración de términos utilizados como son los casos de la acción, la operación, la habilidad y el hábito.

  1. entre la pirámide y el axolotl

    Directory of Open Access Journals (Sweden)

    Paula Andrea Marín Colorado

    2006-01-01

    Full Text Available En este artículo se presenta un acercamiento a la novela Materia dispuesta, del escritor mexicano Juan Villoro. En esta aproximación analítica se pretende dilucidar la conexión entre la obra literaria y el medio en el que se gesta, así como con el momento histórico recreado en la anécdota de la novela (el terremoto ocurrido en Ciudad de México en 1985; lo anterior con el objetivo de establecer la propuesta estética del autor en esta obra y su relación con la visión que construye Materia dispuesta sobre los procesos de Modernidad y Postmodernidad en Latinoamérica. Para tal propósito se recurrirá a las investigaciones literarias y sociológicas de Mijail Bajtín, Zigmunt Bauman, Carlos Monsiváis y Octavio Paz, entre otros.

  2. Burnout Syndrome prevalence of on-call surgeons in a trauma reference hospital and its correlation with weekly workload: cross-sectional study.

    Science.gov (United States)

    Novais, Rodrigo Nobre DE; Rocha, Louise Matos; Eloi, Raissa Jardelino; Santos, Luciano Menezes Dos; Ribeiro, Marina Viegas Moura Rezende; Ramos, Fernando Wagner DA Silva; Lima, Fernando José Camello DE; Sousa-Rodrigues, Célio Fernando DE; Barbosa, Fabiano Timbó

    2016-01-01

    to determine the prevalence of Burnout Syndrome (BS) for surgeons working in referral hospital for trauma in Maceio and to evaluate the possible correlation between BS and weekly workload. cross-sectional study with 43 on-call surgeons at Professor Osvaldo Brandão Vilela General State Hospital, Maceió, between July and December, 2015. A self-administered form was used to evaluate BS through the Maslach Burnout Inventory (MBI) and socio-demographic characteristics among participants. Spearman's S test was used to compare BS and weekly workload. Significant level was 5%. among the surgeons studied, 95.35% were male and the mean age was 43.9 ± 8.95 years. The mean weekly workload on call in trauma was 33.90 ± 16.82 hours. The frequency of high scores in at least one of the three dimensions of MBI was 46.5%. Professional achievement was correlated with weekly workload (P = 0.020). the prevalence of Burnout Syndrome among on-call surgeons in referral hospital for trauma was 46.5%. In this sample there was correlation between weekly workload and the Burnout Syndrome. determinar a prevalência da Síndrome de Burnout (SB) em médicos cirurgiões que trabalham em hospital de referência para o trauma em Maceió e avaliar a possível correlação entre SB e a carga horária semanal de trabalho. estudo transversal com 43 cirurgiões de plantão do Hospital Geral do Estado Professor Osvaldo Brandão Vilela, Maceió, entre julho e dezembro de 2015. Um formulário autoadministrado foi utilizado para avaliar SB por meio do Maslach Burnout Inventory (MBI) e as características sociodemográficas entre os participantes. Foi utilizado o teste de Spearman S para comparar SB e carga horária semanal. O nível de significância foi 5%. entre os cirurgiões estudados, 95,35% eram do sexo masculino e a média de idade foi 43,9±8,95 anos. A média da carga horária semanal de plantão no trauma foi 33,90±16,82 horas. A frequência de pontuações elevadas em pelo menos uma das tr

  3. Ceramic material suitable for repair of a space vehicle component in a microgravity and vacuum environment, method of making same, and method of repairing a space vehicle component

    Science.gov (United States)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2009-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium diboride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  4. Projecte d'integració entre SAP GH - SAP MM - Kàrdex

    OpenAIRE

    Perea Núñez, Yolanda

    2012-01-01

    Projecte d'integració entre dos sistemes SAP (gestió hospitalària i gestió de materials) amb un altre sistema aliè a SAP, el sistema de magatzem de medicaments Kàrdex, mitjançant comunicacions via SAP Process Integration. Proyecto de integración entre dos sistemas SAP (gestión hospitalaria y gestión de materiales) con otro sistema ajeno a SAP, el sistema de almacén de medicamentos Kardex, mediante comunicaciones vía SAP Process Integration.

  5. RELACIÓN ENTRE HABILIDADES SOCIALES Y DESEMPEÑO DOCENTE DESDE LA PERCEPCIÓN DE ESTUDIANTES ADULTOS DE UNIVERSIDAD PRIVADA EN LIMA, PERÚ / RELATIONSHIP BETWEEN TEACHER'S SOCIAL SKILLS AND TEACHING PERFORMANCE FROM THE POINT OF VIEW OF ADULT STUDENTS AT A PRIVATE UNIVERSITY IN LIMA, PERU

    Directory of Open Access Journals (Sweden)

    Marlene Edith Reyes Manrique

    2016-12-01

    Full Text Available RESUMEN:El objetivo del presente estudio fue analizar la relación entre habilidades sociales (HHSS y desempeño docente (DD, desde la percepción del estudiante universitario. Se elaboraron dos escalas tipo Likert de 25 ítems, con cuatro dimensiones validadas a través del juicio de expertos. La muestra fue de 100 estudiantes de una universidad privada de la ciudad de Lima, con edades entre 21 y 46 años. Las dimensiones de las HHSS son: comunicación asertiva, liderazgo, resolución de conflictos y planificación. Las dimensiones del DD son: capacidad docente, emocionalidad, responsabilidad en el desempeño de sus funciones y relaciones interpersonales. El alfa de Cronbach de los resultados alcanza niveles aceptables de .97 para HHSS y de .95 para DD. La correlación entre ambos constructos se realizó aplicando el coeficiente de correlación rho de Spearman, alcanzando una rs de .74 para la correlación inter escala que nos indica una correlación lineal, positiva, moderadamente fuerte, así como correlaciones mayores a .80 entre DD y las dimensiones de las HHSS. Se discuten las implicancias de los resultados encontrados. ABSTRACT: The purpose of this study was to analyze the relation between social skills (SS and teaching performance (TP based on the perception of university students. Two 25-item Likert scales were prepared, with four dimensions validated through the judgment of experts. The sample was of 100 students of a private university in the city of Lima of ages between 21 and 46 years. The dimensions of the SS are: assertive communication, leadership, conflic resolution and planning. The dimensions of the TP are: teaching ability, emotionality, responsibility in the performance of their functions and interpersonal relationships. The Cronbach’s alpha of the results reaches acceptable levels of .97 for SS and .95 for TP. The correlation between both constructs was carried out by applying the Spearman’s rho correlation coefficient

  6. Factores socioculturales y consumo de drogas entre estudiantes universitarios costarricenses

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    Jaime Alonso Caravaca Morera

    2015-01-01

    Full Text Available Investigación cuantitativa de tipo descriptiva-exploratoria, con diseño transversal que examinó el efecto moderador de ciertos factores socio-culturales en el consumo de drogas entre estudiantes universitarios en San José, Costa Rica. La muestra fue conformada por 126 mujeres y 124 hombres de una universidad pública de forma no probabilística. Fue elaborado un cuestionario con cinco escalas ya validadas, que interrogaba sobre la influencia del grupo de pares, las relaciones familiares, el entretenimiento, la espiritualidad y el consumo de drogas. Se utilizó el programa SPSS versión 18 para el análisis estadístico. Se estableció que el 98,4% de los estudiantes reportaron tener por lo menos un amigo que consumía drogas, las drogas más consumidas fueron alcohol, tabaco y marihuana. Se estableció asociación significativa entre algunos factores académicos y culturales con el consumo de drogas legales e ilegales. Se concluye que deben ser implementadas estrategias preventivas considerando la influencia de los factores culturales entre los estudiantes universitarios.

  7. Indústria de tabaco e cidadania: confronto entre redes organizacionais

    OpenAIRE

    Boeira, Sérgio Luís

    2006-01-01

    O artigo aborda a história da indústria de tabaco no Brasil e da formação de sua rede estratégica, bem como da rede dos atores sociais que a contrapõem. Na primeira parte, apresenta-se uma correlação entre a história da produção industrial, do consumo de tabaco e do antitabagismo. Na segunda parte são apresentados os conceitos de rede estratégica e de rede multifragmentária (antifumo), propostos para facilitar a compreensão de alguns dos múltiplos aspectos conflitivos entre as duas redes. A p...

  8. Relación entre variables familiares y el ajuste conyugal

    Directory of Open Access Journals (Sweden)

    Nerea Jiménez-Picón

    2018-04-01

    Full Text Available Resumen: Objetivo: Analizar si las variables familiares tales como tipo de relación de pareja, años de matrimonio, existencia de hijos, número de miembros de la unidad familiar, etapas del ciclo vital familiar, transición entre etapas, apoyo social percibido y/o acontecimientos vitales estresantes se relacionan con el ajuste conyugal. Diseño: Estudio transversal y correlacional mediante encuestas. Emplazamiento: Consultas de atención primaria y unidades de hospitalización de los centros seleccionados de la provincia de Sevilla, España. Participantes: Muestra consecutiva estratificada por cuotas de 369 parejas, mayores de 18 años, heterosexuales, que mantenían una relación de pareja, con o sin hijos, residentes en Sevilla. Mediciones principales: Se emplea cuestionario autoadministrado con las variables sociodemográficas y las escalas Versión Breve de la Escala de Ajuste Diádico, Cuestionario de MOS de Apoyo Social Percibido y Escala de Reajuste Social. Se realizó análisis descriptivo e inferencial con estadísticos de correlación y regresión multivariante. Resultados: Relaciones estadísticamente significativas entre el ajuste conyugal y los años de matrimonio (r = −0,10; p < 0,05, la etapa del ciclo vital familiar (F = 2,65; p < 0,05, la transición entre etapas (rpb = 0,11; p < 0,05 y el apoyo social percibido (r = 0,44; p < 0,001. El modelo de regresión mostró la capacidad predictiva del apoyo social percibido y etapa del ciclo vital familiar (etapa madura-anciana sobre el ajuste conyugal (R2 = 0,21; F = 9,9; DF = 356; p < 0,001. Conclusiones: Desde atención primaria, se puede valorar a las parejas, ofrecer recursos y proporcionar apoyo. También pueden identificarse variables que ayuden a mejorar la relación conyugal. Abstract: Objective: To determine whether family variables, such as type of relationship, years of marriage, existence of offspring, number of members of family, stage of family

  9. FLUJO DE GENES ENTRE FRIJOL COMÚN Y SILVESTRE EN COSTA RICA

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    N\\u00E9stor Chaves-Barrantes

    2009-01-01

    Full Text Available Con el objetivo de analizar el flujo de genes entre frijol común silvestre y cultivado, se determinó el porcentaje de alogamia en condiciones naturales de crecimie nto del frijol silvestre y en estación experimental. En el 2004 se evaluó el cruzamie nto natural entre frijol silvestre mexicano G23511A (Phaseolus vulgaris L. y la línea blanca PAN 68, en la Estación Experimental Fabio Baudrit de la Universidad de Costa Ri ca en Alajuela. Para ello se sembraron dos parcelas experimentales; cada una constó de dos bloques de PAN 68 de 10 surcos (15 m de largo y espacia dos 0,6 m. Entre los bloques y en el borde superior de los mismos, se sembraron tres surcos de frijol silvestre como donantes de polen. Se numeraron las hileras y las plantas de cada una en los bloques de frijol blanco. En Quircot de Ca rtago (área donde crece en forma natural P. vulgaris silvestre, en el 2005 y 2006, se sembraron plantas de frijol comercia l (Vainica de Palo a lo largo de seis sitios junto a las poblaciones de frijol silvestre. En ambas localidades la floración de silvestres y comerciales fue coincidente. Se cosechó toda la semilla de los ensayos y se germinó en bandejas, determinando el porcentaje de alogamia por medio del color morado del hip ocotilo, indicativo de aquellas plántulas cruzadas. En Alajuela el porcentaje de cruza varió entre 0,007 y 0,028 %; mie ntras que en Quircot, entre 0 y 0,199 %.

  10. Um estudo correlacional entre habilidades sociais e traços de personalidade A correlational study of social skills to personality traits

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    José Maurício Haas Bueno

    2001-06-01

    Full Text Available Este trabalho teve como objetivo o desenvolvimento de um estudo correlacional entre habilidades sociais e traços de personalidade segundo o modelo dos cinco grandes fatores. Foram sujeitos da pesquisa 189 estudantes universitários, de ambos os sexos (41 homens e 148 mulheres, de 18 a 59 anos (média 26,3 anos, primeiro-anistas dos cursos de Letras, História, Psicologia, Pedagogia e Biologia. Foram aplicados o Inventário de Habilidades Sociais, que informa sobre (a enfrentamento com risco, (b auto-afirmação na expressão de afeto positivo, (c conversação e desenvoltura social, (d auto-exposição a desconhecidos e a situações novas e (e auto-controle da agressividade a situações aversivas; e um Inventário de Personalidade que informa sobre os cinco grandes fatores: extroversão, socialização, escrupulosidade, neuroticismo e abertura para novas experiências. Encontrou-se que a variância de enfrentamento com risco pode ser explicada principalmente por extroversão e abertura para novas experiências; auto-afirmação na expressão de afetos positivos, por socialização e equilíbrio emocional; conversação e desenvoltura social, pelo conjunto equilibrado de todas os cinco grandes fatores, exceto escrupulosidade; auto-exposição a desconhecidos e a situações novas, por extroversão e equilíbrio emocional; e auto-controle da agressividade por socialização.The purpose of this study was to investigate de correlation of social skills to personality traits by the big five factors model. The Ss were 189 undergraduates, 41 men and 148 women, from 18 to 59 ys. old (mean 26,3 ys. old, freshmen of the Literature, History, Psychology, Pedagogy, and Biology courses. The instruments were the Social Skills Inventory, which informs about (a confront with risk, (b self-affirmation on the positive affect expression, (c conversation and social easiness, (d self-exposure to strangers and new situations, and (e self-control of aggressiveness in

  11. Entre a potência e o poder: Walter Benjamin e Roger Caillois

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    Susana Scramim

    2009-01-01

    Full Text Available http://dx.doi.org/10.5007/1984-784X.2009v9n14p101 A escrita fragmentária empenhada por Benjamim em "Seqüência em Ibiza" e os aforismos do Oráculo Manual y Arte de Prudencia de Gracián  indicam o esboço de uma reflexão sobre o poder na obra de Benjamin a qual se materializará como limiar entre a forma e o informe, entre a autonomia e auto-implicação, entre a obra e a des-obra. Essa reflexão se torna aguda  no impacto provocado em Benjamin pela a leitura  de L´ariditè que Roger Caillois publica juntamente com outros ensaios, em 1938, no Colégio de Sociologia em Paris.

  12. Invalidez por dor nas costas entre segurados da Previdência Social do Brasil

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    Ney Meziat Filho

    2011-06-01

    Full Text Available OBJETIVO: Descrever as aposentadorias por invalidez decorrente de dor nas costas. MÉTODOS: Estudo descritivo com dados do Sistema Único de Informações de Benefícios e dos Anuários Estatísticos da Previdência Social em 2007. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez foi calculada segundo as variáveis idade e sexo, nos estados. Os dias de trabalho perdidos por invalidez decorrente de dor nas costas foram calculados segundo atividade profissional. RESULTADOS: A dor nas costas idiopática foi a primeira causa de invalidez entre as aposentadorias previdenciárias e acidentárias. A maioria dos beneficiários residia em área urbana e era comerciário. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez no Brasil foi de 29,96 por 100.000 contribuintes. Esse valor foi mais elevado entre os homens e entre as pessoas mais velhas. Rondônia exibiu taxa quatro vezes superior ao esperado (RT = 4,05 e a segunda maior taxa, referente à Bahia, foi de aproximadamente duas vezes o esperado (RT = 2,07. Os comerciários foram responsáveis por 96,9% dos dias perdidos por invalidez. CONCLUSÕES: A dor nas costas foi uma importante causa de invalidez em 2007, sobretudo entre comerciários, com grandes diferenças entre os estados.

  13. RELACIÓN ENTRE DIFERENTES PRUEBAS DE CAMPO: FUERZA, POTENCIA Y VELOCIDAD

    OpenAIRE

    Jessenia Hernández Elizondo

    2003-01-01

    Esta investigación tuvo como propósito principal el encontrar por medio de pruebas en las variables de fuerza, potencia y velocidad, la relación matemática existente entre estos tres constructos. Participaron 56 sujetos varones con edades entre 18 y 25 años. Con el fin de responder al objetivo del estudio, se les aplicaron pruebas de campo de fuerza (1RM de sentadilla completa y repeticiones máximas al 80% 60% 40% y 20%), de velocidad (30 metros lanzados y 30 metros sin impulso), y de potenci...

  14. Afetividade entre professor e aluno no processo ensino-aprendizagem

    Directory of Open Access Journals (Sweden)

    Jéssica Simone Galdino Schaefer

    2015-06-01

    Full Text Available Este artigo tem como objetivo analisar as relações de afetividade entre professor e aluno no processo ensino-aprendizagem. Utiliza de metodologia com abordagem qualitativa, observação participante, e entrevistas semi-estruturadas. O lócus da pesquisa foi a Escola Municipal de Educação Básica Lizamara Aparecida Oliva de Almeida em Sinop, entre Fevereiro e Maio de 2014. Enquanto sujeitos, contou-se com professores e alunos do 3º ano do Ensino Fundamental. Dos resultados parciais, verificou-se que mesmo que a afetividade e a aprendizagem sejam reconhecidas teoricamente por Henri Wallon como elos fundamentais para o processo ensino-aprendizagem, ainda não é bem compreendido pelos sujeitos professores. Palavras-chave: psicologia educacional; afetividade; professores e alunos. 

  15. Correlations between deformations, surface state and leak rate in metal to metal contact; Correlations entre deformations, etat de surface et debit de fuite au contact metal-metal

    Energy Technology Data Exchange (ETDEWEB)

    Armand, G; Lapujoulade, J; Paigne, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The study of metal to metal contact from the stand-point of the leak rate has been carried on a copper ring located between two hard-steel flanges. The analysis of the results confirms the hysteresis phenomenon already seen. Some curves (leak rate versus force and leak rate versus true deformation) in semi-logarithmic coordinates are straight lines. Likewise some curves (electrical contact resistance versus force) in bi-logarithmic coordinates are straight lines. All these results can be understood by looking at the conductance introduced by the deformations of the micro-geometry of the surfaces in contact. Some tests carried out in rising the temperature confirm these hypothesis. (authors) [French] L'etude du contact metal-metal du point de vue debit de fuite a ete poursuivie en utilisant un anneau de cuivre place entre brides d'acier dur. L'analyse des resultats confirme le phenomene d'hysteresis deja constate, montre l'influence de l'etat de surface des brides et du joint. Certaines courbes (debit de fuite/force et debit de fuite/deformation rationnelle), en coordonnees semi-logarithmiques, sont des droites. De meme, certaines courbes (resistance de contact/force) en coordonnees bi-logarithmiques, sont des droites. Ces resultats s'interpretent en considerant la conductance produite par la deformation des microgeometries des surfaces en contact. Quelques essais d'elevation de temperature confirment ces resultats. (auteurs)

  16. CONCORDANCIA ENTRE CINCO DEFINICIONES DE SÍNDROME METABÓLICO. CARTAGENA, COLOMBIA

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    Gustavo Mora García

    2012-01-01

    Full Text Available Fundamentos: Durante la última década el síndrome metabólico fue definido en cinco diferentes guías. Con cada definición se modifica la capacidad predictiva del síndrome sobre la enfermedad cardiovascular. El objetivo del presente estudio fue determinar el grado de concordancia entre estas cinco guías en Cartagena (Colombia. Métodos: Se realizó un estudio de corte transversal en adultos. El tamaño mínimo de muestra se estimó con información del censo DANE 2005. Se realizó un muestreo por conglomerados bietápico que incluyó 670 individuos. Para estimar la prevalencia del síndrome se aplicaron las guías OMS (Organización Mundial de la Salud, AHA/NHBLI (Asociación Americana del Corazón, ATPIII (Panel de Tratamiento de Adultos, IDF (Federación Internacional de Diabetes y JIS (Declaración Provisional Conjunta. La concordancia fue calculada con el índice Kappa de Cohen. Resultados: Según las guías JIS, IDF, ATPIII, AHA/NHBLI y OMS, la prevalencia de síndrome metabólico fue del 36,3%, 35,1%, 30,3%, 24,2% y 4,9% respectivamente. La concordancia entre JIS e IDF fue de 0,893 mientras que el índice entre estas guías y AHA/NHBLI fue de 0,778 y 0,750 respectivamente. El ATP III tuvo una concordancia más baja con JIS e IDF (0,711 y 0,645, respectivamente pero con AHA/NHLBI la concordancia fue de 0,863. La OMS presentó un acuerdo con las demás guías de entre 0,14 y 0,16. Conclusiones: Existe concordancia significativa entre las cuatro guías más recientes. Los puntos de corte para obesidad abdominal podrían justificar las diferencias encontradas.

  17. Entre la Venadita y la Medusa

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    Valcárcel, Amelia

    2008-06-01

    Full Text Available Feminism has made in the last decades relevant advances towards equity between men and women in western societies. However, both mysogyny and gynophobia are still at work, giving as a result a «deflation of expectations» among women who enter the worlds of politics, information, corporations, economic power, knowledge, religion or art, and find a glass ceiling in full operation. The paper focuses on women artists, examines the anger expressed in feminist art as an answer to exclusion, and argues for feminist strategies of analysis and correction of inequalities.

    El feminismo ha conseguido en los últimos años importantes avances hacia la igualdad entre hombres y mujeres en las sociedades occidentales. Y, sin embargo, tanto la misoginia como la ginofobia siguen vigentes, provocando una «deflación de expectativas » entre las mujeres que se incorporan a los mundos de la política, la información, las organizaciones empresariales, el poder económico, el saber, la religión o la creatividad, y se topan con el techo de cristal a pleno funcionamiento. El artículo se centra en las mujeres creadoras para examinar la cólera expresada en el arte feminista como respuesta a la exclusión y defender estrategias feministas de análisis y corrección de desigualdades.

  18. Fatores associados ao consumo de álcool e drogas entre estudantes universitários

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    Leonardo V E Rueda Silva

    2006-04-01

    Full Text Available OBJETIVO: Estudos recentes mostram o uso preocupante de álcool e drogas entre universitários. O objetivo do trabalho foi verificar o grau de associação entre o estilo de vida e situação socioeconômica e o uso de álcool, tabaco, medicamentos e "drogas ilícitas" nos últimos 12 meses entre universitários. MÉTODOS: A amostra compreendeu 926 alunos da área de Ciências Biológicas de uma universidade do Município de São Paulo, os quais responderam a questionário anônimo e de auto-preenchimento em 2000 e 2001. Foram utilizados os testes de análise de variância e qui-quadrado para verificar a correlação entre o uso de substâncias e as variáveis estudadas. RESULTADOS: Entre os alunos com alguma religião, o consumo de álcool foi de 83,1%, o de tabaco, 20,7% e o de "drogas ilícitas", 24,6%, nesse período. Entre os alunos que não possuíam religião, o consumo nas três categorias foi superior nos últimos 12 meses: álcool (89,3%, tabaco (27,7% e "drogas ilícitas" (37,7%. A renda familiar mensal mostrou-se relacionada ao uso de álcool e "drogas ilícitas" (p<0,001 para ambos. Os alunos que utilizaram tabaco e "drogas ilícitas" apresentavam mais horas livres nos dias úteis do que os alunos que não fumavam no período analisado (p=0,033 e p=0,008, respectivamente. CONCLUSÕES: O consumo de substâncias psicoativas entre os alunos estudados foi comum, indicando a necessidade de implementação de medidas para reduzir tal consumo. Alunos com renda familiar alta e sem religião podem ser considerados com maior risco de consumo de drogas nessa população.

  19. Compatibilidad sexual entre dos tipos de Hylocerus (Cactaceae

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    Roberta Castillo M

    2003-09-01

    Full Text Available Dos de los tipos de pitahaya mas cultivados en la Península de Yucatán, México, difieren principalmente por el color de su cáscara, el primero es de color rojo (Uqroo1, perteneciente a Hylocereus undatus, mientras que en el segundo es color amarillo claro (Uqroo2, hasta el momento también identificado como H. undatus; este último es mas dulce. En ambos tipos de pitahayas, se realizaron autopolinizaciones y polinizaciones cruzadas directas y recíprocas, con el propósito de evaluar el efecto en la cantidad de frutos que lograron su desarrollo. Se midieron algunas variables para detectar la influencia del progenitor paterno en algunas características del fruto. Los testigos se obtuvieron de flores polinizadas libremente. El diseño experimental utilizado fue completamente al azar, con 15 repeticiones por tratamiento. Se encontró que Uqroo1 es autocompatible, mientras que Uqroo2 es autoincompatible. Los testigos de ambos tipos alcanzaron el mismo peso, y los frutos de Uqroo2 logrados por polinización cruzada tuvieron un peso similar al de los testigos o fueron significativamente mas pesados. Algunas variables resultaron positivamente correlacionados; el coeficiente entre el número de semillas y el peso total del fruto fue de r = 0.84. La correlación mas alta (r = 0.97 resultó entre el peso total y el peso de la pulpa. En los frutos obtenidos por polinización cruzada prevalecieron las características del progenitor materno. Se recomienda cultivar la Pitahaya blanca con otro tipo de pitahaya, además de Uqroo1There are two types of pitahaya that are cultivated in Yucatan Peninsula of Mexico. They differ mainly in the skin color of the fruit, one of them has a red skin (Uqroo1, while the other has a light yellow skin (Uqroo2 both belong to Hylocereus undatus (Haworth Britt. & Rose. The yellow skin pitahaya is the sweetest. The studies were conducted using the methods of self pollination and cross pollination, with direct crosses and

  20. Estenose degenerativa do canal lombar: correlação entre o índice de Oswestry e imagem de ressonância magnética Estenosis degenerativa del canal lumbar: correlación entre el índice de Oswestry y la resonancia magnética Degenerative lumbar spinal stenosis: correlation between Oswestry index and magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Wagner Pasqualini

    2012-12-01

    Full Text Available OBJETIVOS: Verificar a relação entre o grau de estenose do canal lombar (ECL com a ressonância nuclear magnética (RM e a gravidade da disfunção, de acordo com o Índice de Oswestry em pacientes com ECL e em controles. MÉTODOS: Vinte e três pacientes com diagnóstico de ECL foram comparados com grupo controle de 17 voluntários. Todos foram submetidos a RM e responderam ao questionário de Oswestry. A análise estatística utilizou o teste exato de Fisher, de Mann-Whitney e de Spearman. RESULTADOS: Dor lombar foi a queixa mais frequente em ambos os grupos. O índice de Oswestry mostrou disfunção, em média, em 45,69% no grupo ECL e 11,60% no controle. A RM revelou que a área longitudinal do saco dural, o diâmetro do canal e os recessos laterais e forames estavam igualmente alterados em ambos os grupos. CONCLUSÕES: Não houve correlação entre o grau de estenose e o índice de Oswestry nos dois grupos.OBJETIVOS: Investigar la relación entre el grado de estenosis de canal lumbar (ECL con imágenes de resonancia magnética (RM y la gravedad de la disfunción de acuerdo con el Índice de Oswestry en pacientes con ECL y controles. MÉTODOS: Veintitrés pacientes con un diagnóstico de ECL se compararon con un grupo control de 17 voluntarios. Todos los pacientes fueron sometidos a resonancia magnética y completaron el cuestionario Oswestry. Para el análisis estadístico se utilizó la prueba exacta de Fisher, Mann-Whitney y de Spearman. RESULTADOS: El dolor de espalda es la queja más frecuente en ambos grupos. El índice de disfunción de Oswestry mostró en promedio 45,69% para el grupo ECL y 11,60% para el grupo control. La RM demostró que el área longitudinal del saco dural, el diámetro del canal y de los agujeros y las cavidades laterales se han cambiado de manera similar en ambos grupos. CONCLUSIONES: No se encontró correlación entre el grado de estenosis y el índice de Oswestry en ambos grupos.OBJECTIVES: To verify the

  1. Vacinação contra a hepatite B entre cirurgiões dentistas

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    Martins Andréa Maria Eleutério de Barros Lima

    2003-01-01

    Full Text Available OBJETIVO: Inquéritos sorológicos realizados em diversos países mostraram uma maior prevalência da infecção pelo vírus da hepatite B (VHB em dentistas, especialmente entre os cirurgiões, do que na população geral. O estudo realizado objetivou determinar a prevalência e os fatores associados à vacinação contra hepatite B (HB entre os dentistas e investigar as principais razões alegadas para a não vacinação e vacinação incompleta. MÉTODOS: Foi conduzido um inquérito entre 299 cirurgiões dentistas residentes em Montes Claros, MG, por meio de questionário auto-aplicável. Foi determinada a prevalência de vacinação segundo o número de doses e os fatores associados à não vacinação e à vacinação incompleta através de regressão logística multinomial. RESULTADOS: Dos 299 questionários distribuídos, 296 (99% foram respondidos. Destes, 74,9% tomaram três doses; 14%, duas doses; 2%, uma dose e 10% não foram vacinados. A vacinação completa foi maior entre os que relataram fazer exclusivamente cirurgia e/ou periodontia (89%. A principal razão alegada para a não vacinação ou vacinação incompleta foi a necessitade de maiores informações. A não vacinação foi mais freqüente entre aqueles com mais de 40 anos (OR=8,62; IC 95%: 1,88-39,41 e os que não se reciclaram nos dois anos prévios ao inquérito (OR=2,72; IC 95%: 1,02-7,22. A vacinação incompleta foi maior entre os que não usam luva no trabalho (OR=2,32; IC 95%: 1,08-4,97. CONCLUSÃO: A falta de informação, possivelmente relacionada a menor reciclagem profissional, parece ser um dos principais fatores limitantes da vacinação.

  2. Correlação entre as classificações de Pfirrmann e Modic na degeneração do disco intervertebral lombar Correspondencia entre las clasificaciones de Pfirrmann y Modic en la degeneración del disco intervertebral lumbar Correlation between Pfirrmann and Modic classifications in the degeneration of lumbar intervertebral disc

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    Marcio Squassoni Leite

    2010-12-01

    con Pfirrmann tipo V, y el 36,4% de las alteraciones Modic 1 fueron por igual entre Pfirrmann tipo IV y V. Se encontró una asociación estadísticamente significativa entre los cambios de Modic y Pfirrmann (pOBJECTIVE: to correlate the changes found in the lumbar magnetic resonance imaging according to Modic and Pfirrmann classifications. METHODS: lumbar spine resonances of 54 outpatients were selected (23 men and 31 women, who were already under investigation because of their comorbidity. According to their degree of Pfirrmann classification, 264 intervertebral discs (L1 to S1 were classified. The presence of signal abnormalities of the vertebral body was recorded as Modic classification. The χ2 mwas applied, adopting significance levels below 0.05 (a=5%. RESULTS: The mean age studied was of 48.4 years (26-77 years. A higher prevalence of Pfirrmann type IV (31.1% was observed. In 88.3% of the sample, Modic was absent, and also Modic 3; 60% of Modic 2 was related to Pfirrmann type V, and 36.4% of Modic 1 was equally distributed among Pfirrmann type IV and V. Statistically significant association between Modic changes and Pfirrmann (p<0.001 was found. CONCLUSION: there was a clear association between the classifications studied, comparing the stages of Pfirrmann (IV and V with Modic type 1 and 2.

  3. Corposições entre o ver, o dizer e o agir

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    Catarina Mendes Resende

    Full Text Available Resumo Este artigo enuncia as questões que mobilizam o coletivo de investigação “Corposições: Profanações entre afeto, performatividade e território”, explicitando o “como”, “onde” e “quando” os campos de atuação de seus integrantes se imbricam para construir um corpo comum. A partir de suas principais ferramentas de trabalho - a Composição em Tempo Real de João Fiadeiro e o Modo Operativo AND de Fernanda Eugenio - o jogo proposto pelo grupo é o de partilhar suas experiências, dando visibilidade ao que desestabiliza, ventila e amplia suas práticas e discursos. Tal proposição implica modos de ver específicos - a articulação entre corporeidade, afeto, território e performatividade - e modos de agir - uma investigação que é experimentação e laboratório, na qual são performadas intervenções entre dança e clínica.

  4. Relaciones entre organizaciones y stakeholders: necesidad de una interacción mutua entre los diversos grupos de interés

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    Jorge Suárez Tirado

    2007-12-01

    Full Text Available En este ensayo intentaré explicar las relaciones y los riesgos existentes entre organizaciones y stakeholders (grupos de interés; adicionalmente, realizaré algunas observaciones al enfoque clásico planteado por Milton Friedman, sin el ánimo de entrar a explicar las características del entorno económico, político y social de la época (1970, e intentaré argumentar que en las circunstancias actuales (niveles de pobreza, aumento en la brecha social, problemas medioambientales, etc., las empresas tienen compromisos con los stakeholders y con la comunidad en general, que van más allá de la generación de utilidades para los propietarios. Posteriormente presentaré de una forma muy breve algunas herramientas que permiten comunicar el impacto de la empresa sobre la sociedad y en particular sobre los diversos stakeholders, como lo son las cuentas de excedente y el balance social que se constituyen en la principal herramienta de comunicación entre la empresa y los diversos grupos de interés o stakeholders

  5. El Ciberacoso entre los estudiantes de Colombia: una investigación exploratoria

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    Giulia Mura

    2013-12-01

    Full Text Available El ciberacoso es un fenómeno relacionado con internet, reconocido y en crecimiento. Aunque el enfoque de la investigación en este campo está expandiéndose rápidamente, la mayoría de las investigaciones se centraron en las experiencias de adolescentes en países industrializados, como los de Europa occidental o países anglosajones. Pero, los jóvenes de los países en desarrollo ¿están expuestos a los mismos riesgos? Para responder a esta pregunta, este trabajo presenta una parte de los resultados de un proyecto más amplio, y centra su atención en la incidencia de episodios de ciberacoso entre los estudiantes de secundaria en Colombia. Los datos se recogieron sobre una muestra de 359 estudiantes, 64.1% varones y 35.9% mujeres, entre los 13 y los 19 años de edad, utilizando un cuestionario entregado en horario escolar. El análisis demuestra que los episodios de ciberacoso están bastante extendidos en el grupo de la muestra; teniendo en cuenta que más del 60% de los jóvenes entrevistados estuvo involucrado (ya sea como víctima o como acosador en al menos 2 episodios en los 6 meses anteriores a la investigación. Las diferencias entre los sexos han sido analizadas, pero no han dado resultados significativos. En conclusión este estudio pone en evidencia la necesidad de una investigación más profunda y amplia del ciberacoso, tanto entre la población masculina como entre la femenina, de los así llamados "países en desarrollo", porque parece que la difusión de éste fenómeno está afectando también a la juventud de éstos países.

  6. Creencias sobre la insuficiencia renal crónica entre expertos y profanos

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    Esperanza Vélez Vélez

    2013-09-01

    Full Text Available Objetivo: Identificar las creencias y representaciones sobre la insuficiencia renal crónica (IRC en pacientes, población general y expertos. Metodología: Estudio descriptivo transversal que analiza una muestra de 120 participantes seleccionados por muestreo no probabilístico por cuotas. Se crearon cinco grupos de estudio en función de su nivel de interacción con la enfermedad. La herramienta utilizada fue el Cuestionario de Creencias Sobre la Enfermedad. Resultados: Identidad, Controlabilidad, Mutabilidad, Responsabilidad Personal y Azar no presentan diferencias significativas entre los grupos estudiados. El factor Causas muestra diferencias estadísticamente significativas entre el grupo de pacientes con universitarios de ciencias de la salud y expertos (p<0,001 y entre otros universitarios con universitarios ciencias de la salud y expertos (p<0.001. El factor Incapacidad muestra diferencias significativas entre pacientes, universitarios y población general (p<0,001 y entre expertos con otros universitarios y población general (p<0,001. Los pacientes ofrecen un menor número de síntomas asociados tanto a la IRC como a la hemodiálisis (HD. Y en cuanto a las causas, las de origen biológico y conductuales son las más consideradas por todos los grupos. Solo el grupo de pacientes en HD considera el azar factor causal de la enfermedad. Conclusiones: En oposición al modelo científico, pacientes y población general comparten la idea de que la IRC es curable, depende en gran medida del azar y de hábitos de conducta y es menos grave de lo que opinan expertos. La experiencia con la enfermedad aporta más información (no necesariamente conocimiento que es recordada en función de la utilidad para lograr un mayor bienestar o una mejora de los cuidados.

  7. Prevalence and correlates of physical fighting among school-going adolescents in Santiago, Chile Prevalencia e correlaciones de la lucha física entre adolescentes escolares en Santiago de Chile, Chile

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    Emmanuel Rudatsikira

    2008-09-01

    Full Text Available OBJECTIVE: There is a growing interest in injury as a public health issue across the world. There is paucity of data on the prevalence and social correlates of non-fatal interpersonal violence in low- and middle-income income nations. The objective of this study was to estimate the prevalence of, and associated factors for physical fighting among school-going adolescents in Santiago, Chile. METHOD: We conducted a secondary analysis of the Chilean Global School-Based Health Survey conducted in 2004 in Santiago. We aimed to assess the prevalence and social correlates of having been involved in a physical fight in the prior 12 months. RESULTS: Of the 2111 respondents, 40.7% (54.3% males and 26.6% females reported having been in a physical fight in the prior 12 months. Males were more likely to have been in a physical fight than females [OR = 3.89, 95% CI (3.11, 4.85]. Substance use (cigarette smoking, drinking alcohol, and using drugs and bullying victimization were positively associated with fighting [OR = 3.05, 95% CI (2.40, 3.87 for substance use, and OR = 1.65, 95% CI (1.32, 2.05 for bullying]. Parental supervision was negatively associated with physical fighting [OR = 0.62, 95% CI (0.50, 0.78]. CONCLUSION: We have estimated the prevalence of having engaged in a physical fight among in-school adolescents in Santiago, Chile. We have found that the prevalence is similar to what has been reported in diverse settings in Africa, Europe and North America.OBJETIVO: Existe un creciente interés en el daño como un asunto de salud pública a través del mundo. Hay escasez de datos en la prevalencia y correlaciones sociales de violencia interpersonal no fatal, en naciones con bajos y medianos ingresos. El objetivo de este estudio fue estimar la prevalencia y el factor asociado a lucha física entre estudiantes adolescentes en Santiago, Chile. MÉTODO: Hemos conducido un análisis secundario de la Encuesta Global Chilena de Salud Basada en Escuelas

  8. Generalización del método de correlaciones canónicas aplicado a un problema de economía (Generalization of the canonical correlation method applied to an economy problem

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    Jorge Luis Azor Hernández

    2018-03-01

    Full Text Available Resumen. El Análisis de Correlaciones Canónicas (CCA desarrollado por Hotelling entre 1935 y 1936 es un método utilizado para estudiar las relaciones existentes entre dos conjuntos de variables. En 1968 Carroll introdujo una generalización de este método que permite analizar simultáneamente más de dos conjuntos de datos. Otra extensión de CCA es el Análisis de Correlaciones Canónicas Funcional que estudia las relaciones entre dos conjuntos de variables cuando estas transcurren en el tiempo. En este artículo se analiza, mediante estos métodos, la relación entre las ventas y el número de empleados en un problema de la economía mexicana English abstract. Canonical Correlation Analysis (CCA developed by Hotelling between 1935 and 1936 is a method used to study the relationships between two sets of variables. In 1968 Carroll introduced a generalization of this method to simultaneously analyze more than two datasets. Another extension of CCA is Functional Canonical Correlation Analysis that studies the relationships between two sets of variables when they pass in time. In this article, the relationship between sales and the number of employees in a problem of the Mexican economy is analyzed through these methods.

  9. Relación entre conducta parental y adherencia al tratamiento en diabetes infantil

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    Mónica María Novoa Gómez

    2008-01-01

    Full Text Available En este artículo, enmarcado en la psicología de la salud, se pretende identificar la relación que existe entre la conducta parental y la adherencia al tratamiento a partir de un diseño no-experimental de tipo transversal descriptivo correlacional, en una muestra de niños con diabetes tipo I, entre 8 y 11 años de edad, con un tiempo desde el diagnóstico de entre uno y tres años. Los resultados analizados señalan la relación que existe entre los comportamientos que engloba la variable de conducta parental y adherencia al tratamiento, pudiendo incluso diferenciar aquellos comportamientos más representativos para cada categoría; así por ejemplo, se encontró que la comunicación afectiva es el comportamiento parental que más está correlacionado con las conductas de adhesión. Con respecto a las conductas de adhesión al tratamiento, la dieta fue la conducta de este tipo que más se correlacionó con comportamientos parentales.

  10. ENTRE IDEOLOGIA E UTOPIA: A DIALÉTICA DA IMAGINAÇÃO EM MANNHEIM

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    Mateus Augusto de Oliveira

    2017-07-01

    Full Text Available O objetivo deste trabalho é analisar o conceito de utopia elaborado pelo sociólogo húngaro Karl Mannheim. Para tanto, estudaremos o papel desempenhado pela obra Ideologia e utopia no pensamento de Mannheim. O livro é a carta de fundação da sociologia do conhecimento como disciplina autônoma. Mostraremos como Ideologia e utopia desenvolve uma aproximação entre imaginário e política. Mannheim argumenta que toda sociedade se alicerça em ficções, símbolos, mitos e ritos. O sociólogo distancia-se de Marx e Engels ao criticar a distinção entre consciência alienada e consciência esclarecida, ciência e ideologia. No cerne da sociologia do conhecimento desenvolvida por Mannheim está uma polarização entre ideologia e utopia, definida pelo filósofo Paul Ricoeur como “dialética da imaginação”. Para Mannheim, o conceito de ‘utopia’ se desenvolveria em contraposição à noção de ‘ideologia’: a tensão entre um e outro estaria na base de toda comunidade.

  11. Asociación entre agenesia dental y maloclusión en pacientes pediátricos

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    A. Carolina Medina

    2013-07-01

    Full Text Available Introducción: La agenesia dental es la anomalía del desarrollo más frecuente en el ser humano, asociándose a maloclusiones y alteraciones funcionales. Objetivo: El objetivo de la presente investigación es determinar la asociación entre la agenesia de dientes permanentes y la presencia de maloclusiones en pacientes pediátricos en el área Metropolitana de Caracas, Venezuela. Material y métodos: Fueron evaluados 1.188 radiografías panorámicas y 648 registros ortodóncicos de pacientes sanos con edades entre 5 y 18 años, registrando agenesia de dientes permanentes, exceptuando terceros molares. La maloclusión se diagnosticó según Angle. Fueron calculados estadísticos descriptivos, diferencias entre promedios y correlaciones entre variables (t de Student, rho de Pearson, p=0,05, odds ratio. Resultados: La prevalencia de agenesia fue 5,6%, siendo la media 1,64 y afectando mayormente al sexo femenino (1,44:1. Los dientes más afectados fueron segundos premolares inferiores (35,19%, e incisivos laterales superiores (30,55%. La prevalencia de maloclusión fue mayor en el grupo con agenesia dental (Clase I 52%, Clase II 31%, Clase III 17% al comparar con el grupo control (Clase I 77%, Clase II 14%, Clase III 9%; habiendo correlación estadísticamente significativa entre el número de dientes ausentes y Clase III. Conclusión: La prevalencia y distribución de agenesia dental variaron entre géneros, siendo el femenino el más afectado. Hubo correlación positiva estadísticamente significativa entre el número de dientes afectados y la maloclusión Clase III.

  12. Effects of energy content and energy density of pre-portioned entrées on energy intake.

    Science.gov (United States)

    Blatt, Alexandria D; Williams, Rachel A; Roe, Liane S; Rolls, Barbara J

    2012-10-01

    Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on 1 day a week for 4 weeks. Each meal included a compulsory, manipulated pre-portioned entrée followed by a variety of unmanipulated discretionary foods that were consumed ad libitum. Across conditions, the entrées were varied in both energy content and ED between a standard level (100%) and a reduced level (64%). Results showed that in men, decreases in the energy content and ED of pre-portioned entrées acted independently and added together to reduce daily energy intake (both P kcal/day; P lunch, but at dinner and for the entire day the effects depended on the interaction of the two factors (P daily energy intake in women by 14% (289 ± 35 kcal/day; P daily energy intake and could influence the effectiveness of such foods for weight management.

  13. L’approche sociopsychologique de Horkheimer, entre Fromm et Adorno

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    Katia Genel

    2010-08-01

    Full Text Available Le cadre du programme interdisciplinaire de recherche défini par Max Horkheimer dans les années 1930 doit beaucoup à Erich Fromm, qui a introduit la psychologie sociale dans la Théorie critique de la société. Or, une décennie plus tard, Fromm est la cible privilégiée des attaques et sa théorie apparaît désormais comme incompatible avec les positions défendues par Horkheimer et Adorno. Partant de ces tensions qui ont marqué l’histoire de l’École de Francfort, le présent article vise à éclaircir le déplacement qu’elles traduisent sur le plan épistémologique. Si Horkheimer et Fromm partagent des prémisses communes, le premier, dans son travail avec Adorno, se rapproche de manière croissante de la doctrine freudienne alors que le second s’en éloigne. Nous voudrions montrer que l’accord entre Fromm et Horkheimer fut surtout négatif puisqu’il portait sur la critique de Freud : les divergences entre les deux penseurs apparaissent clairement, dès lors qu’on pose en profondeur la question de l’usage de la psychanalyse pour analyser l’un des problèmes centraux de la théorie de la société, l’antagonisme entre individu et société.

  14. Relación entre variables neurocognitivas y personalidad en delincuentes

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    Juan Antonio Becerra García

    2014-12-01

    Full Text Available Recientes estudios muestran que rasgos de personalidad del Modelo de los Cinco Factores y funciones neurocognitivas frontales comparten una misma base neurobiológica. En población penitenciaria las relaciones entre estas funciones y rasgos ha sido poco explorada. Este estudio pretende examinar la relación entre personalidad y funciones neurocognitivas en delincuentes y determinar si las medidas de funcionamiento neurocognitivo frontal contribuyen a predecir algún porcentaje de varianza en rasgos de personalidad de muestras penitenciarias. Noventa y nueve hombres (distribuidos en grupos: agresores sexuales de adultos, delincuentes no sexuales y grupo control realizaron el Inventario de Personalidad NEO de Cinco Factores (NEO-FFI y el Trail Making Test (TMT, partes A y B. La ejecución en la parte A del TMT se relaciono con el nivel de Extraversión de los delincuentes sexuales y con el nivel de Neuroticismo de delincuentes no sexuales y explica un porcentaje significativo de la varianza de estos dominios de personalidad en ambos grupos. En conclusión, la relación entre el funcionamiento neurocognitivo y la personalidad parece ser diferente en función del tipo de delito cometido, aunque los resultados deben ser interpretados de forma preliminar.

  15. Relaciones entre el sueño y la adicción

    OpenAIRE

    Cañellas, Francesca; de Lecea, Luis

    2012-01-01

    La interacción entre los trastornos del sueño y el abuso de sustancias es ya conocida, pero seguramente más compleja de lo que se pensaba. Existe tanto una relación positiva entre tener un trastorno por uso de substancias y sufrir un trastorno de sueño, como viceversa. Los efectos sobre el sueño dependen de la substancia utilizada, pero se ha demostrado que tanto durante su uso como en período de abstinencia los consumidores tienen diferentes problemas de sueño y fundamentalmente un sueño más...

  16. Association Between Conformation Traits and Reproductive Traits in Holstein Cows in the Department of Antioquia - Colombia / Asociación entre Características de Conformación y Reproductivas en Vacas Holstein del Departamento de Antioquia - Colombia

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    Stephania Madrid Gaviria

    2014-06-01

    Full Text Available Abstract. Conformation traits have been related with reproductive parameters and can be used as their indicators. These traits appear earlier in life than reproductive traits and, thus, may allow for faster selection of prolific animals. In order to estimate the phenotypic association between conformation and reproductive traits, 8,037 records from 139 Holstein cow herds were analyzed. The analysis of association was done with a generalized linear model, regressionanalysis and Pearson correlation coefficient. The results showed that the association between conformation traits tends to be low to medium (0.00 – 0.46; the highest association was for rear udder height and rear udder weight (0.46, while the lowest was for chest width and central ligament (-0.0024. Conformation traits that showed a significant effect on reproductive traits were body andudder compound, angularity, stature and rear udder width. The highest regression coefficient was for calving interval and body compound (-43.13 days; the lowest was for services per conception and rear udder width (-0.063 services. Phenotypic correlations with reproductive traits were low (0.00 to 0.04. The highest correlation was for services per conception and foot angle (0.04; the lowest was for calving interval and rear legs rear view (0.00. These results indicate that there are not phenotypic associations betweenconformation traits and reproductive parameters. It is important to estimate genetic correlation and determinate their importance and possibilities for use in genetic improvement programs. / Resumen. Las características de conformación han sido relacionadas con parámetros reproductivos y pueden usarse como indicadores de estos. Estas aparecen más rápido en la vida que las reproductivas, permitiendo una selección rápida de individuos prolíficos. Para estimar la asociación fenotípica entre características de conformación y reproductivas, se analizaron 8

  17. Co-variabilidad de la temperatura superficial del mar entre cuencas del Hemisferio Sur

    Directory of Open Access Journals (Sweden)

    Ana Laura Berman

    2011-12-01

    Full Text Available En este trabajo se estudian relaciones estadísticas entre diferentes regiones de los océanos del Hemisferio Sur en todo el espacio tiempo-frecuencia durante los últimos cincuenta años aplicando la metodología de transformada ondeletas de coherencia a promedios anuales de anomalías mensuales de temperatura superficial del mar. Entre los resultados más relevantes encontrados debe mencionarse que las regiones del oeste y centro del Pacífico tropical tienen una estrecha relación en oscilaciones menores a 8 años y en oscilaciones alrededor de 12 años pero notables desacoples son detectados en el resto del espacio de frecuencias. Por otra parte, la relación entre las regiones del oeste y del este del Pacífico tropical es significativa sólo en oscilaciones menores a 8 años con una clara interrupción durante la década de 1980. Importantes conexiones en oscilaciones interdecadales son detectadas entre las regiones del oeste y centro del Pacifico subtropical. En el Océano Atlántico se encuentran relaciones significativas en un amplio rango de frecuencias entre las regiones del oeste y, especialmente, entre las regiones tropicales mientras que en el Océano Indico solo se observan relaciones importantes entre áreas subtropicales en oscilaciones decadales e interdecadales. El análisis también revela fuertes conexiones entre las tres cuencas oceánicas en diferentes bandas de frecuencia.Relations among different regions of the Southern Hemisphere oceans in the whole time-frequency space during the last fifty years are studied applying the methodology of Wavelet Coherence Analysis to annual means of monthly anomalies of sea surface temperature. Among the most relevant results, it must be mentioned that the western and central regions of the tropical Pacific have a close relation in oscillations shorter than 8 years and in oscillations around 12 years but important disconnections are detected in the rest of the space of frequencies

  18. Prevalencia de consumo de tabaco entre las medicas y enfermeras de la comunidad de Madrid

    Directory of Open Access Journals (Sweden)

    Fernández Ruiz Mª Luisa

    1999-01-01

    Full Text Available FUNDAMENTOS: El tabaquismo es responsable de una elevada mortalidad y morbilidad en nuestro pais. El tabaquismo de los profesionales de la salud tiene influencia sobre los hábitos de la población. En España, el tabaquismo esta incrementándose entre las mujeres. El objetivo de nuestro estudio es estudiar la prevalencia de consumo de tabaco entre las médicas y enfermeras de la Comunidad de Madrid, así como sus actitudes y conocimientos respecto al tabaquismo. MÉTODOS: Se ha realizado un estudio descriptivo transversal entre las mujeres profesionales de la salud (médicas y enfermeras de la Comunidad de Madrid, mediante una encuesta sobre hábito tabáquico, en un muestreo polietápico por conglomerados. RESULTADOS: Se han estudiado 1.235 profesionales ( 435 médicas y 800 enfermeras. El 43,07% del total son fumadoras, siendo el tabaquismo mayor en las enfermeras (47,62% que en las médicas (34,71%, y entre quienes trabajan en atención especializada (46,68% que entre las que lo hacen en atención primaria (35,29%. El tabaquismo fue diferente en ambas profesiones.según la edad En las médicas era menor tabaquismo en las edades entre 20 y 30 años (22,88%, y en las enfermeras este grupo de edad era el que tenia un mayor porcentaje de fumadoras (52,38%. Eran exfumadoras el 18,3% del total de las encuestadas, y el 64,65% de las que fumaban señalaron que habían intentado dejarlo. Un 2,93% fumaban delante de los/as pacientes, y un 14,94% pensaban que debía permitirse fumar en las salas de espera. El 27,46% creían que estaba permitido fumar en su area de trabajo, y el 90,64% señaló que se fumaba habitualmente en las salas de uso común del personal sanitario, y un 30,37% respondió que existía un lugar especifico para fumar en el centro de trabajo. CONCLUSIONES: La prevalencia de tabaquismo entre las profesionales de la salud, médicas y enfermeras, de la Comunidad de Madrid, es elevada, superior a la de la población general de igual edad

  19. La discapacidad entre poblaciones refugiadas y afectadas por conflictos

    OpenAIRE

    Reilly, Rachael

    2010-01-01

    La Comisión de Mujeres Refugiadas lanzó en el año 2007 un importante proyecto de investigación para evaluar la situación de las personas con discapacidad entre las poblaciones desplazadas o afectadas por conflictos.

  20. Test de Rorscharch: respuestas diferenciales entre pacientes con y sin intento suicida

    Directory of Open Access Journals (Sweden)

    Alejandro Cuadra-Peralta

    2009-12-01

    Full Text Available Este estudio tuvo como objetivo identificar respuestas diferenciales entre grupos de No-pacientes, pacientes diagnosticados con Depresión, pacientes diagnosticados con Trastorno de Personalidad y con Depresión y pacientes con intento suicida a través de los indicadores de la Escala de Potencial suicida, propuesto por Passalacqua, Herrera y Orcoyen (1997. La muestra total fue de 70 sujetos de sexo femenino, con grupos de aproximadamente 18 personas cada uno. Se encontró diferencia significativa en seis indicadores entre los cuatro grupos y en diez indicadores entre los pacientes con intento suicida y los demás participantes. Con estos indicadores se realizó un análisis discriminante, encontrándose una alta capacidad para diferenciar los diferentes subgrupos, en especial a grupo de pacientes con intento suicida y el resto de las personas. Se entrega una formula para calcular la probabilidad de pertenencia al grupo de intento de suicidio.

  1. Comparación de caracteres corporales y del veneno de Bothrops alternatus entre poblaciones de las provincias de Buenos Aires y Entre Ríos, Argentina

    Directory of Open Access Journals (Sweden)

    Rocco, Daniela Marisa

    2011-11-01

    Full Text Available Comparamos caracteres corporales y producción de veneno de ejemplares de Bothrops alternatus de una población aislada geográficamente (Olavarría, región de Tandilia, Buenos Aires con otra en su área de distribución continua de Concordia (Entre Ríos. Estudiamos el largo corporal, peso, separación entre dientes inoculadores, cantidad de veneno y de proteínas en el veneno por ejemplar. No se hallaron diferencias en los caracteres estudiados entre ambas poblaciones (p > 0.05. Las hembras fueron mayores que los machos en ambas muestras, entre un 12-18% (p 0.5; Olavarría: 142 ± 65 mg/animal, Concordia: 160 ± 80 mg/animal, aún ajustando la cantidad de veneno producida respecto al tamaño, mediante el cociente veneno/largo corporal (p >0.6. Tampoco hubo diferencias en el contenido proteico, siendo para ambas muestras de 0.697 ± 0.096 mg de proteínas/mg de veneno seco. Nuestros datos sugieren que los ejemplares de la población aislada de Tandilia no presentan variaciones en el tamaño corporal o en la cantidad de veneno producida, respecto a los ejemplares de Concordia. Some corporal characters and venom yield of adult specimens of Bothrops alternatus from the isolated region of Olavarría (Tandilian Region, Buenos Aires and the region of continuous distribution of Concordia (Entre Ríos were compared. Corporal length, weight, separation between fangs, venom yield by snake and the amount of protein in the venom were determined. No differences in the distinct characters from specimens from both regions were found (p > 0.05. Females were greater than males in both samples, 12-18% (p 0.5; Olavarría= 142 ± 65 mg / animal, Concordia= 161 ± 80 mg / animal even adjusting the venom yield with the corporal length by the relation mg of venom / corporal length (p > 0.6. No differences were observed in the protein content of the dry venom which was of 0.697 ± 0.096 mg of protein / mg of dry venom. From the study of these samples, it could be

  2. Pineal yolk sac tumor: correlation between neuroimaging and pathological findings Tumor do seio endodérmico da pineal: correlação entre os achados patológicos e de neuroimagem

    Directory of Open Access Journals (Sweden)

    Taísa Davaus

    2007-06-01

    Full Text Available A 17-year-old boy presented with somnolence and mental confusion. Physical examination demonstrated motor disturbances. Laboratorial investigation showed elevated levels of alpha-fetoprotein in serum and cerebrospinal fluid. The CT scan revealed a heterogeneous mass at the pineal region. At the MRI, this lesion was hypointense on T1 and hyperintense on T2-weighted images, enhancing after contrast administration. The patient underwent a surgical biopsy, which defined the diagnosis of yolk sac tumor. We emphasize the correlation of neuroimaging and pathological findings of this rare pineal region tumor.Um menino de 17 anos de idade apresentou-se com sonolência e confusão mental. O exame físico demonstrou distúrbios motores. A investigação laboratorial revelou aumento dos níveis de alfafetoproteína no soro e no líquor. A TC de crânio revelou massa heterogênea na região pineal. À RM, a lesão era hipointensa em T1 e hiperintensa em T2, com realce após a administração de contraste. O paciente foi submetido a biópsia cirúrgica, a qual definiu o diagnóstico de tumor do seio endodérmico. Enfatizamos a correlação entre os achados patológicos e de neuroimagem deste raro tumor da região pineal.

  3. Fatores associados à Síndrome de Burnout entre profissionais intensivistas de hospital universitário.

    Directory of Open Access Journals (Sweden)

    Claidson Felipe Campanha ALKIMIM

    2015-02-01

    Full Text Available Objetivo: Avaliar prevalências da Síndrome de Burnout (SB e dimensões -exaustão emocional (EE, despersonalização (DE e baixa realização profissional (BRP- entre profissionais intensivistas e identificar suas associações com variáveis individuais, ocupacionais e organizacionais. Métodos: Estudo analítico entre intensivistas de hospital universitário de Montes Claros-MG. Utilizou-se para coleta de dados Maslach Burnout Inventory, Critério de Classificação Econômica Brasil e questionário “variáveis individuais, ocupacionais e organizacionais”. Resultados: As prevalências da SB e dimensões (EE-DE-BRP foram respectivamente: 34,0%; 16,9%; 19,4% e 17,9%. Por análise multivariada registrou-se maior chance de desenvolver SB entre homens às mulheres; pessoas que identificam o trabalho como “às vezes/quase sempre/sempre” estressante àquelas que o identificam como “nunca/quase nunca” estressante; e pessoas que “não concordam e nem discordam/concordam em parte/concordam totalmente” que escolheriam outra profissão com a mesma remuneração àquelas que “discordam totalmente/em parte” na escolha de outra profissão. Maior chance de desenvolver EE: entre “solteiros/divorciados/desquitados” aos casados; entre os que têm “ruim/regular” motivação com o trabalho àqueles cuja motivação é “boa/muito boa/excelente”; e entre aqueles que percebem que “às vezes/quase sempre/sempre” as pessoas são tratadas desigualmente àqueles que percebem que “nunca/quase nunca” existe tratamento desigual. Maior chance de desenvolver DE: entre aqueles que “nunca consumiram bebida alcóolica” àqueles que “consomem/não consomem mais”; e entre aqueles com “ruim/regular” expectativa profissional àqueles com expectativa “boa/muito boa/excelente”. Conclusão: As prevalências registradas são preocupantes sendo que SB e dimensão DE associaram-se às variáveis individuais e ocupacionais e EE

  4. Reduced-portion entrées in a worksite and restaurant setting: impact on food consumption and waste.

    Science.gov (United States)

    Berkowitz, Sarah; Marquart, Len; Mykerezi, Elton; Degeneffe, Dennis; Reicks, Marla

    2016-11-01

    Large portion sizes in restaurants have been identified as a public health risk. The purpose of the present study was to determine whether customers in two different food-service operator segments (non-commercial worksite cafeteria and commercial upscale restaurant) would select reduced-portion menu items and the impact of selecting reduced-portion menu items on energy and nutrient intakes and plate waste. Consumption and plate waste data were collected for 5 weeks before and 7 weeks after introduction of five reduced-size entrées in a worksite lunch cafeteria and for 3 weeks before and 4 weeks after introduction of five reduced-size dinner entrées in a restaurant setting. Full-size entrées were available throughout the entire study periods. A worksite cafeteria and a commercial upscale restaurant in a large US Midwestern metropolitan area. Adult worksite employees and restaurant patrons. Reduced-size entrées accounted for 5·3-12·8 % and 18·8-31·3 % of total entrées selected in the worksite and restaurant settings, respectively. Food waste, energy intake and intakes of total fat, saturated fat, cholesterol, Na, fibre, Ca, K and Fe were significantly lower when both full- and reduced-size entrées were served in the worksite setting and in the restaurant setting compared with when only full-size entrées were served. A relatively small proportion of reduced-size entrées were selected but still resulted in reductions in overall energy and nutrient intakes. These outcomes could serve as the foundation for future studies to determine strategies to enhance acceptance of reduced-portion menu items in restaurant settings.

  5. Variabilidad espacial y temporal de larvas de jurel Trachurus murphyien el Perú entre 1966 –2010

    Directory of Open Access Journals (Sweden)

    Patricia Ayón

    2013-10-01

    Full Text Available El análisis espacial y temporal de larvas de jurel Trachurus murphyien el mar peruano entre los años 1966 y 2010 confirma su presencia constante durante todo el periodo estudiado. En general, en este periodo la abundancia de larvas de jurel T. murphyimuestra una tendencia ligeramente ascendente destacándose cambios en la distribución espacial y una alta variabilidad interanual, con cortos periodos de alta abundancia promedio, intercalados con periodos más prolongados y de baja abundancia. El promedio anual estimado varió entre 3 y 79 larvas/ m2 . La distribución espacial presentó tres periodos importantes: uno con mayores densidades de larvas al sur de los 14°S, entre 1970 y 1979; cambió hacia el norte de esta latitud, entre 1980 y 1999; y otro de mayor densidad al sur de los 18°S, en el último periodo 2000 – 2010. Los centros de gravedad de la distribución de larvas presentaron tres periodos muy notorios: fueron más costeros hacia el sur de los 14°S, entre 1966 y1978; más oceánicos y al norte de los 14°S, entre 1979 y 1994; y con una posición intermedia entre 1995 – 2010. Se discute la relación entre la distribución de las larvas con las variables oceanográficas y la distribución de T. murphyiadultos y juveniles, además se destaca que el mar del Perú es un centro principal y permanente de actividad reproductiva de esta especie.

  6. Lowering the environmental impact of high-kappa/ metal gate stack surface preparation processes

    Science.gov (United States)

    Zamani, Davoud

    ABSTRACT Hafnium based oxides and silicates are promising high-κ dielectrics to replace SiO2 as gate material for state-of-the-art semiconductor devices. However, integrating these new high-κ materials into the existing complementary metal-oxide semiconductor (CMOS) process remains a challenge. One particular area of concern is the use of large amounts of HF during wet etching of hafnium based oxides and silicates. The patterning of thin films of these materials is accomplished by wet etching in HF solutions. The use of HF allows dissolution of hafnium as an anionic fluoride complex. Etch selectivity with respect to SiO2 is achieved by appropriately diluting the solutions and using slightly elevated temperatures. From an ESH point of view, it would be beneficial to develop methods which would lower the use of HF. The first objective of this study is to find new chemistries and developments of new wet etch methods to reduce fluoride consumption during wet etching of hafnium based high-κ materials. Another related issue with major environmental impact is the usage of large amounts of rinsing water for removal of HF in post-etch cleaning step. Both of these require a better understanding of the HF interaction with the high-κ surface during the etching, cleaning, and rinsing processes. During the rinse, the cleaning chemical is removed from the wafers. Ensuring optimal resource usage and cycle time during the rinse requires a sound understanding and quantitative description of the transport effects that dominate the removal rate of the cleaning chemicals from the surfaces. Multiple processes, such as desorption and re-adsorption, diffusion, migration and convection, all factor into the removal rate of the cleaning chemical during the rinse. Any of these processes can be the removal rate limiting process, the bottleneck of the rinse. In fact, the process limiting the removal rate generally changes as the rinse progresses, offering the opportunity to save resources

  7. Convergencias y divergencias entre los sistemas interamericano y el europeo de derechos humanos

    OpenAIRE

    Gasparoto, Ana Lucía

    2014-01-01

    Este trabajo tiene la finalidad de puntear las convergencias y las divergencias existentes entre la Corte Interamericana de Derechos Humanos y el Tribunal Europeo de Derechos Humanos, encima con la adopción del Protocolo 11 del Convenio Europeo para la Protección de los Derechos Humanos y las Libertades Fundamentales y su impacto en el Sistema Europeo de Derechos Humanos. Igualmente se analisa las relaciones entre las dos Cortes.

  8. Das vizinhanças entre o feminino e a loucura

    Directory of Open Access Journals (Sweden)

    Elizabeth Cristina Landi

    Full Text Available O tema da loucura feminina se apresenta frequentemente na clínica psicanalítica por meio de sujeitos neuróticos. Questiona-se neste artigo as proximidades entre psicose e a loucura que se apresenta no discurso das mulheres neuróticas. As identificações iniciais, por meio das quais a criança se aliena ao desejo do Outro, determinam certa loucura, não restrita apenas aos psicóticos. Para um sujeito do sexo feminino, que passa pelo tortuoso processo de tornar-se mulher, a loucura é uma possibilidade, pois uma mulher, por encontrar-se dividida entre o gozo masculino e o feminino, se aproxima da loucura, mas é não louca-de-todo.

  9. Associações entre auto-eficácia para atividades ocupacionais e interesses em adolescentes Associations between self-efficacy to occupational activities and interests in adolescents

    Directory of Open Access Journals (Sweden)

    Maiana Farias Oliveira Nunes

    2011-01-01

    Full Text Available O objetivo desse estudo foi analisar a relação entre a auto-eficácia para atividades ocupacionais e suas fontes e interesses, construtos importantes no contexto da Orientação Profissional. Participaram da pesquisa 289 adolescentes, do estado de São Paulo, que responderam a Escala de Auto-eficácia para Atividades Ocupacionais-EAAOc e o Self-Directed Search e 107 alunos que responderam a EAAOc e a Escala de Aconselhamento Profissional. Houve correlações significativas entre auto-eficácia e interesses (r entre - 0,25 e 0,27. A auto-eficácia Realista e Social, juntamente com a variável sexo, apresentou capacidade preditiva significativa para os respectivos tipos de interesses. É discutida a coerência da associação entre os tipos de auto-eficácia para atividades ocupacionais e os respectivos tipos de interesses.The aim of this study was to analyze the association between self-efficacy for occupational activities and its sources and interest, which are important constructs for Vocational Guidance. Two hundred eighty nine adolescents answered the Self-efficacy Scale for Occupational Activities (SSOA and the Self-Directed Search, and 107 answered the SSOA and the Professional Counseling Scale. All participants lived in São Paulo at the moment of the survey. There were significant correlations between self-efficacy and interests (r ranging from -0.25 to 0.27. Realistic and Social self-efficacy combined with gender showed a significant predictive power to their respective types of interest. We discussed the coherence between self-efficacy for occupational activities and their respective interests.

  10. Genes candidatos para la comorbilidad entre trastornos de ansiedad y trastornos adictivos.

    OpenAIRE

    Gallego Moreno, Xavier

    2008-01-01

    Esta Tesis Doctoral ha consistido en el estudio de los mecanismos implicados en la comorbilidad entre el abuso de drogas y los trastornos de ansiedad, así como en las regiones cerebrales responsables de la coexistencia de estos dos trastornos en modelos transgénicos. Nos hemos centrado en dos grandes familias de genes, que podrían actuar como interfaz genético en la comorbilidad entre trastornos de ansiedad y de abuso de sustancias: neurotrofinas por su intervención en el neurodesarrollo y en...

  11. La problematica de la demarcacion entre ciencia y pseudociencia y sus implicaciones en la educacion cientifica

    Science.gov (United States)

    Jimenez Tolentino, Dinorah

    2011-12-01

    En la sociedad prevalece una tendencia generalizada hacia la inclusion de creencias y practicas pseudocientificas. Esta investigacion responde a la necesidad de analizar como la proliferacion de las pseudociencias afecta la vision que tienen los estudiantes universitarios sobre las ciencias naturales. A tales efectos, la investigadora describe las concepciones epistemologicas que tienen los estudiantes sobre las ciencias y las pseudociencias e identifica los criterios de demarcacion, entre un area y otra, que se derivan de estas concepciones. De igual modo, esta identifica las creencias y practicas pseudocientificas de mayor arraigo entre los estudiantes, destacando, a su vez, la razon de ser de las mismas. Por ultimo, la investigadora analiza las implicaciones educativas de la problematica de la demarcacion entre ciencia y pseudociencia. La investigacion es de naturaleza mixta, enmarcada en los paradigmas empirico- analitico y cualitativo. El proceso investigativo se llevo a cabo mediante la administracion del cuestionario Criterios para la demarcacion entre ciencia y pseudociencia. La parte cualitativa estuvo enmarcada en el diseno de estudio de caso, recopilando informacion mediante entrevistas semiestructuradas en dos grupos focales. La poblacion de estudio estuvo constituida por estudiantes universitarios del nivel subgraduado de la Universidad Central de Bayamon. Los resultados del estudio reflejaron las concepciones erroneas de los estudiantes sobre la naturaleza de las ciencias y las pseudociencias. Con respecto a la demarcacion entre ciencia y pseudociencia, el criterio imperante entre los universitarios es el de la verificabilidad, considerando la aplicacion del metodo cientifico como el metodo para demostrar la veracidad de las teorias cientificas. Las creencias y practicas pseudocientificas no son muy frecuentes entre los universitarios. Estos atribuyen las mismas a la prevalencia de elementos supersticiosos y al engano a que es sometida la poblacion

  12. Contribution have the survey of the transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta; Contribution a l'etude de la transformation {sup 181}Hf {yields} {sup 181}Ta (17 {mu}s) {yields} {sup 181}Ta

    Energy Technology Data Exchange (ETDEWEB)

    Baullini, R; Chaminade, R; Desneiges, P; Grjebine, T; Quidort, J; Wahl, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1953-07-01

    The metastable state of Ta, whose period is around 20 microseconds, has been discovered by De BENEDETTI and Mc GOWAM who done measurements of deferred coincidences between the particles beta and the electrons of conversion given out by the hafnium radiated by thermal neutrons. We measured the period of {sup 181}Ta{sup *} by measures of deferred coincidences {beta}-e{sup -} and {beta}-{gamma}. A method of survey of the specter of photons amplitudes emitted by {sup 181}Ta{sup *} has been fit. This method permitted to solve the presence of {gamma} in the radiation emitted in synchronism with the deexcitation of {sup 181}Ta{sup *}. Finally in a last chapter, we propose a method of dosage of the {sup 181}Hf in presence of other radioelements. (M.B.) [French] L'etat metastable de Ta, dont la periode est voisine de 20 microsecondes, a ete decouvert par DE BENEDETTI et Mc GOWAM qui effectuaient des mesures de coincidences differees entre les particules beta et les electrons de conversion emis par du hafnium irradie par des neutrons thermiques. Nous avons mesure la periode de {sup 181}Ta{sup *} par des mesures de coincidences differees {beta}-e{sup -} et {beta}-{gamma}. Une methode d'etude du spectre d'amplitudes des photons emis par {sup 181}Ta{sup *} a ete mise au point. Cette methode a permis d'eclaircir la presence de {gamma} dans le rayonnement emis en synchronisme avec la desexcitation de {sup 181}Ta{sup *}. Enfin dans un dernier chapitre, on proposera une methode de dosage du {sup 181}Hf en presence d'autres radioelements. (M.B.)

  13. RELAÇÕES ENTRE ENSINO E APRENDIZAGEM NA EJA

    Directory of Open Access Journals (Sweden)

    José Moisés Nunes da Silva

    2010-01-01

    Full Text Available Este artigo tem por objetivo apresentar uma distinção clara e objetiva entre os processos de ensinar e aprender. Nessa perspectiva, primeiramente destaca a educação no contexto e como parte integrante dos processos de transformações do mundo contemporâneo. Em seguida, sustentado por diversos autores, discute-se a distinção entre ensinar e aprender. Espera-se contribuir para uma reflexão sobre a prática pedagógica docente e da necessidade de melhoria do processo de ensino e aprendizagem a fim de possibilitar uma educação em consonância com a concepção de formação integral do cidadão, à medida que tal distinção seja introjetada pelos professores. PALAVRAS-CHAVE: Ensinar. Aprender. Aprendizagem do jovem e do adulto.

  14. Association entre les hormones sexuelles, les marqueurs de ...

    African Journals Online (AJOL)

    Introduction: Le présent travail se propose d'étudier la relation entre les hormones sexuelles, notamment l'oestradiol et l'indice de l'oestradiol libre, le sulfate de déhydroépiandrosterone et la sex hormone binding globulin, les marqueurs de remodelage osseux et la densité minérale osseuse chez une population de ...

  15. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.

    1979-01-01

    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  16. Relações entre geografia e natureza

    Directory of Open Access Journals (Sweden)

    Jérome FOURNIER

    2001-12-01

    Full Text Available Este artigo aborda as relações entre geografia e natureza a partir dos seguintes tópicos: A geografia - uma ciência dos lugares e dos homens? Como definir a geografia física? A biogeografia e as relações com as disciplinas conexas. As contribuições da teoria da ecologia da paisagem. A paisagem deve ser estudada a partir de uma perspectiva sistêmica - geosistêmica, portanto interdisciplinar.

  17. Os significados do uso de álcool entre jovens quilombolas

    Directory of Open Access Journals (Sweden)

    Roseane Amorim da Silva

    2016-01-01

    Full Text Available Esta investigación tuvo como objetivo investigar los significados que tiene el consumo de alcohol entre los jóvenes de dos comunidades quilombolas, Castainho y Estivas, ubicadas en la ciudad de Garanhuns -PE (Brasil. La investigación fue de corte cualitativo y se desarrolló en dos etapas. En una primera etapa, se utilizó como técnica metodológica la observación participante durante nuestra inserción en las comunidades, y en la segunda etapa realizamos entrevistas semi-estructuradas a hombres y mujeres jóvenes. Para el análisis de los datos, se tomó como base teórica la interseccionalidad de los marcadores sociales de género, raza/etnia y clase social. Los jóvenes consumen alcohol en diferentes momentos y por diferentes razones: para divertirse, socializar entre pares, hacer frente a situaciones difíciles y/o enfrentar estados emocionales desagradables, entre otros. Es importante resaltar los efectos que estos marcadores sociales tienen en la vida de los jóvenes, lo cual también repercute en el consumo de alcohol y la necesidad de considerar estos factores en las prácticas de prevención y promoción de la salud para tratar de contribuir a la calidad de vida de la juventud.

  18. Sonolência e consumo de carboidratos entre motoristas de caminhão

    OpenAIRE

    Andressa Juliane Martins

    2013-01-01

    Introdução - Há evidências de que o aumento do consumo de carboidratos esteja associado à sonolência. Quando realizado à noite, o consumo de carboidratos parece ser um fator que afeta o desempenho no trabalho. Paradoxalmente, o trabalho noturno levaria ao aumento da ingestão de alimentos ricos em carboidratos como consequência da privação de sono. Objetivo - Verificar a existência de correlação entre a sonolência e consumo de carboidratos entre motoristas de caminhão. Métodos - Participaram d...

  19. ASOCIACIÓN ENTRE VALORES DE TRABAJO, INTERESES PROFESIONALES Y RASGOS DE PERSONALIDAD

    OpenAIRE

    Pinto, Lariana Paula; Noronha, Ana Paula Porto; Rueda, Fabián Javier Marín

    2017-01-01

    Resumen Este estudio tuvo como objetivo investigar la asociación entre intereses profesionales y valores de trabajo, y entre valores de trabajo y rasgos de personalidad. Participaron 281 universitarios, con edad media de 23.97 años, de los cursos de Administración, Psicología, Filosofía y Teología, del Estado de San Pablo, Brasil. Fueron aplicados tres instrumentos (Escala de Evaluación de los Valores de Trabajo, Cuestionario de Búsqueda Auto-Dirigida y Batería Factorial de Personalidad). Los...

  20. Autopercepção da saúde bucal entre idosos brasileiros Autopercepción de la salud bucal entre ancianos brasileños Self-perceived oral health among Brazilian elderly individuals

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    Andréa Maria Eleutério de Barros Lima Martins

    2010-10-01

    Full Text Available OBJETIVO: Identificar os fatores associados à autopercepção da saúde bucal entre idosos brasileiros. MÉTODOS: Utilizaram-se dados do Projeto SB Brasil, realizado em 20022003. Foi examinada e entrevistada amostra probabilística de 5.349 idosos de 65 a 74 anos agrupados em dentados e edentados. A variável dependente foi autopercepção da condição de saúde bucal e as independentes foram: local de moradia, características individuais, comportamentos relacionados à saúde, condições objetivas de saúde e condições subjetivas relacionadas à saúde. Foram conduzidas análises descritivas e análises de regressão linear múltipla hierárquica. RESULTADOS: Nos dois grupos a autopercepção da saúde bucal foi considerada positiva, apesar das precárias condições de saúde bucal entre os idosos. No modelo final, o local de moradia e as características individuais pouco contribuíram para explicar a variabilidade da autopercepção. Entre dentados, o uso de serviços odontológicos esteve associado ao desfecho, e as condições objetivas e subjetivas se mostraram associadas nos dois grupos. Entre dentados e edentados, o R² para o ambiente externo foi de 0,00; com o acréscimo das características individuais, respectivamente, 0,05 e 0,02; incluindo o comportamento relacionado à saúde, 0,06 e 0,03; acrescentando as condições objetivas de saúde, 0,11 e 0,04; adicionando as condições subjetivas relacionadas à saúde foram 0,50 e 0,43. Foi possível explicar 50% da variabilidade da autopercepção entre dentados e 43% entre edentados. CONCLUSÕES: Os principais fatores associados à autopercepção da saúde bucal como positiva nos dois grupos foram a autopercepção da aparência como ótima seguida pela autopercepção da mastigação como positiva. O terceiro fator associado, entre dentados, foi o relato de nenhuma necessidade de tratamento odontológico e, entre edentados, a autopercepção da fala.OBJETIVO: Identificar los

  1. Relación entre el aporte fiscal directo, la calidad del cuerpo docente y la producción científica de las instituciones pertenecientes al Consejo de Rectores de las universidades chilenas

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    Paulina Manríquez Maulén

    2015-03-01

    Full Text Available La búsqueda del conocimiento como uno de los principales focos que tienen las universidades se encuentra estrechamente relacionada con la calidad docente. Materializar este concepto implica establecer una relación entre la producción científica en Chile, la calidad docente y el Aporte Fiscal Directo (AFD que es destinado a las universidades pertenecientes al CRUCH, éste es el objetivo de esta investigación. Para el análisis, primero se busca determinar si existe correlación entre las variables de estudio. Posteriormente, se obtiene el índice de correlación simple entre las mismas. Los resultados muestran una correlación muy alta entre cada una de las variables. Además, se realiza este mismo procedimiento segmentando a las universidades según su ubicación, en la Región Metropolitana o en regiones y si son estatales o no, obteniendo resultados similares. De forma complementaria, se realiza un análisis con la técnica de regresión lineal simple en donde se obtiene que sólo un pequeño porcentaje de las publicaciones científicas provenientes de las instituciones pertenecientes el CRUCH estarían siendo publicadas por otro tipo de investigadores. The pursuit of knowledge as one of the main focuses of universities is closely related to quality. To materialize this concept in establishing the relationship of scienti­fic production in Chile, quality of faculty and Direct Fiscal Funding (AFD destinated to universities belonging to the CRUCH, is the aim of this research. For analysis, a scatter plot is created to intuitively determine if there is a correlation between the study variables. Subsequently, the rate of simple correlation is obtained between the same variables, which results in a very high correlation between each one of the variables. In addition, this same procedure is performed after segmenting universities by location, in the metropolitan area or other regions, and by being state-owned or not, obtaining similar results

  2. Relación entre la fuerza máxima en squat y acciones de salto, sprint y golpeo de balón. (Relationship among maximal strength in squat exercise, jump, sprint and kicking ball performance.

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    Alfredo Arija Blázquez

    2008-01-01

    Full Text Available ResumenEl objetivo del presente estudio fue analizar las posibles relaciones entre la fuerza máxima en squat y accionesexplosivas de salto, sprint y golpeo de balón. Para ello, se contó con una muestra formada por estudiantes de Ciencias del Deporte (N= 16; 19,6 ± 1,7 años de sexo masculino (con escasa experiencia en el entrenamiento de fuerza, que llevaron a cabo un test de 1RM en squat (calculándose el peso levantado, la fuerza media total y la fuerza dinámica máxima, tests de salto vertical (SJ, CMJ y CMJa, un test de sprint de 20 m (con mediciones de tiempo cada 5 m, y un test de golpeo con el pie donde se calculaba la velocidad del balón. Se encontraron coeficientes de correlación moderados (entre 0,52 y 0,67 y significativos de las medidas de fuerza máxima y las alturas de salto, mientras que los coeficientes obtenidos entre los tiempos de sprint y dichas medidas de fuerza máxima se situaron entre -0,06 y -0,32, no siendo ninguno de ellos significativo; al igual que tampoco fueron significativos los coeficientes de correlación de las medidas de fuerza máxima y la velocidad de tiro, se situaron entre 0,25 y 0,34. Por tanto, la relación entre la fuerza máxima en squat y la altura de salto en sujetos con escasa experiencia en el entrenamiento de fuerza resultó moderada, mientras que no parece existir relación con el tiempo de sprint y la velocidad de tiro.AbstractThe purpose of the present study was to analyze the possible relationships between maximal strength insquat exercise and jump, sprint and kicking ball actions. Sixteen males sport science students (19,6 ± 1,7years, with little experience in strength training, performed a 1RM in squat exercise (from which liftedweight, the total average- and maximal-dynamic strength was assessed, vertical jump (SJ, CMJ and CMJa, a 20 m sprint test (with time measurement every 5 m, and a kicking ball test where the velocity of the ball was calculated. Moderate (0,52 - 0,67 and

  3. Ausencia de asociación entre marcadores inflamatorios y síntomas depresivos en adultos colombianos: un estudio transversal

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    Gerardo Mantilla-Mora

    2009-12-01

    Full Text Available Antecedentes: varios informes relacionan la presencia de asociación entre trastorno depresivo mayor y niveles séricos elevados de biomarcadores de inflamación. Objetivo: evaluar la asociación entre síntomas depresivos y los niveles séricos de proteína C reactiva (PCR e interleucina 6 (IL6. Metodología: se adelantó un estudio transversal entre los empleados adultos de una Escuela de Medicina. Para correlacionar los niveles de PCR e IL6 con el puntaje de la prueba CES-D, se utilizó regresión lineal y binomial. Resultados: un total de 159 personas participaron: 55.4% hombres, de entre 22 y 73 años de edad (media: 40.8 años. Hay asociación entre los IL6 > 3 pg/mL y obesidad, y entre el log de los niveles de PCR con ser mayor de 48 años y tener alteraciones inflamatorias de la cavidad oral. No se encontró asociación entre los niveles de PCR o IL6 con el puntaje de la CES-D. Conclusión: En esta población, no se encontró asociación entre los niveles séricos de IL6 y PCR con la presencia de síntomas depresivos.

  4. Comparação entre as análises auditiva e acústica nas disartrias Comparison between auditory-perceptual and acoustic analyses in dysarthrias

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    Karin Zazo Ortiz

    2008-01-01

    Full Text Available OBJETIVO: Comparar os dados da análise perceptivo-auditiva (subjetiva com os dados da análise acústica (objetiva. MÉTODOS: Quarenta e dois pacientes disártricos, com diagnósticos neurológicos definidos, 21 do sexo masculino e 21 do sexo feminino foram submetidos à análise perceptual-auditiva e acústica. Todos os pacientes foram submetidos à gravação da voz, tendo sido avaliados, na análise auditiva, tipo de voz, ressonância (equilibrada, hipernasal ou laringo-faríngea, loudness (adequado, diminuído ou aumentado, pitch (adequado, grave, agudo ataque vocal (isocrônico, brusco ou soproso, e estabilidade (estável ou instável. Para a análise acústica foram utilizados os programas GRAM 5.1.7; para a análise da qualidade vocal e comportamento dos harmônicos na espectrografia e o Programa Vox Metria, para a obtenção das medidas objetivas. RESULTADOS: A comparação entre os achados das análises auditiva e acústica em sua maioria não foi significante, ou seja, não houve uma relação direta entre os achados subjetivos e os dados objetivos. Houve diferença estatisticamente significante apenas entre voz soprosa e Shimmer alterado (p=0,048 e entre a definição dos harmônicos e voz soprosa (p=0,040, sendo assim, observou-se correlação entre a presença de ruído à emissão e soprosidade. CONCLUSÕES: As análises perceptual-auditiva e acústica forneceram dados diferentes, porém complementares, auxiliando, de forma conjunta, no diagnóstico clínico das disartrias.PURPOSE: To compare data found in auditory-perceptual analyses (subjective and acoustic analyses (objective in dysarthric patients. METHODS: Forty-two patients with well defined neurological diagnosis, 21 male and 21 female, were evaluated in auditory-perceptual parameters and acoustic measures. All patients had their voices recorded. Auditory-perceptual voice analyses were made considering type of voice, resonance (balanced, hipernasal or laryngopharyngeal

  5. Correlação entre os Aspectos Laparoscópicos e os Achados Histológicos das Lesões Endometrióticas Peritoneais Correlation Between Laparoscopic Aspects and Histologic Findings in Peritoneal Endometriotic Lesions

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    Francesco Antonio Viscomi

    2002-03-01

    Full Text Available Objetivos: avaliar a correlação entre os aspectos laparoscópicos e os achados histológicos estromais incluindo, a profundidade da lesão endometriótica peritoneal, e na relação com a teoria evolutiva da endometriose. Métodos: foram selecionadas para o estudo 67 pacientes submetidas à laparoscopia por algia pélvica, infertilidade, tumor anexial e outras indicações. A avaliação laparoscópica baseou-se no aspecto visual do implante suspeito de endometriose peritoneal, o qual foi biopsiado. De acordo com o aspecto laparoscópico, as lesões foram agrupadas em: grupo V - lesões vermelhas, grupo N - lesões negras e grupo B - lesões brancas. Os parâmetros histológicos estudados foram: profundidade da lesão, presença de hemossiderina no estroma, vascularização estromal e presença de fibrose no estroma. Resultados: a profundidade da lesão mostrou diferenças estatisticamente significantes entre os grupos de estudo. As lesões vermelhas mostraram-se superficiais em 100% dos casos. As lesões negras apresentaram-se superficiais em 55,6%, intermediárias em 38,9% e profundas em 5,5%. As lesões brancas mostraram-se superficiais em 28%, intermediárias em 68% e profundas em 4%. A presença de hemossiderina no estroma se mostrou equivalente nos 3 grupos. A presença de vasos no estroma da lesão endometriótica, que foi classificada de I a III de acordo com a quantidade, demonstrou diferenças significantes entre os 3 grupos, sendo que a vascularização exuberante (grau III esteve presente em 60% das lesões vermelhas e em 10% das lesões brancas. A presença de tecido fibrótico na lesão endometriótica apresentou diferenças estatisticamente significantes nos 3 grupos de estudo, sendo mais freqüente no grupo B (lesões brancas, com 70,6%. Conclusão: as variáveis analisadas nos diferentes grupos de estudo demostraram diferença significantes entre os grupos, reforçando a teoria evolutiva da endometriose peritoneal.Purpose: to

  6. Medidas de adesão entre agregado e ligante asfáltico

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    Kamilla Lima Vasconcelos

    2009-06-01

    Full Text Available

    A adesão entre agregado e ligante asfáltico vem sendo apontada como uma propriedade de grande importância para a causa de defeitos encontrados em pavimentos asfálticos, tais como trincas por fadiga, e dano por umidade. Diferentes mecanismos existem na literatura para explicar a adesão entre os dois materiais, porém, estes mecanismos podem ser resumidos em três grandes grupos: inter- travamento mecânico, adesão física, e interação química. A ocorrência de mais de um mecanismo simultaneamente parece ser o fenô- meno mais provável, sendo a relevância de cada um dependente das características físicas e químicas do agregado e do ligante asfálti- co. No presente trabalho, dois procedimentos foram utilizados para acessar a adesão entre agregado e ligante. O primeiro constou do cálculo do trabalho de adesão através da energia livre de superfície dos materiais envolvidos e o segundo, da determinação da entalpia de imersão quando soluções de asfalto são postas em contato com o agregado. Todos os materiais usados foram provenientes da biblio- teca de referência do SHRP sendo um pedregulho como agregado, e três diferentes ligantes asfálticos. Os resultados mostraram a capa- cidade do microcalorímetro em detectar possíveis interações químicas na adesão entre agregado e ligante asfáltico, em conjunto com adesão física. A presença de grupos funcionais mais fortemente adsorvidos pela superfície dos agregados justificou os maiores valores de entalpia de imersão para as combinações onde esses grupos se encontravam presentes.

    Abstract Adhesion between the asphalt binder and the aggregate is critical to the performance and durability of asphalt mixtures. According to the literature, distresses mechanisms such as fatigue cracking and moisture induced damage are correlated to the nature and quality of adhesion between these two materials. Different mechanisms already exist to explain

  7. Cruzamiento interespecífico entre Aedes aegypti y Aedes albopictus en el laboratorio

    OpenAIRE

    Martínez López, Yanisley; Martinez Pérez, Yanet; Acosta Rodríguez, Miriam; Fuentes González, Omar

    2014-01-01

    Introducción: existen algunos estudios realizados para verificar el posible apareamiento interespecífico, pero solo algunos trabajos han obtenido resultados positivos en este fenómeno. Objetivo: probar la posibilidad de obtener huevos viables del cruce entre Aedes aegypti y Aedes albopictus. Métodos: experimentos de apareamiento recíproco entre Aedes aegypti procedentes del insectario del Departamento de Control de Vectores del Instituto de Medicina Tropical "Pedro Kourí" y una población de A...

  8. Determinantes da Distribuição da (Desigualdade de Gênero entre os Estados Brasileiros

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    Adriana Bruscato Bortoluzzo

    2016-03-01

    Full Text Available Resumo A igualdade de gênero é fundamental para um desenvolvimento econômico sustentável. O Brasil, apesar de ser uma das maiores economias do mundo, ainda precisa de um grande avanço no sentido de conquistar uma sociedade mais igualitária entre homens e mulheres quando comparado a países do mesmo porte econômico. O presente estudo faz uma análise da evolução da igualdade de gênero no Brasil entre 1997 e 2012, e quais os impactos da globalização, do desenvolvimento econômico e de medidas de bem-estar sobre a distribuição da igualdade de gênero entre os estados brasileiros. Para isso, foi utilizada a metodologia econométrica de dados em painel. Os resultados mostram que a igualdade de gênero aumentou no período e que, além disso, a globalização, mensurada com base no investimento direto estrangeiro e no acesso da população a aparelhos de televisão, elevou a igualdade entre os sexos no Brasil.

  9. Posibles relaciones entre el hábitat de Lycosa fasciiventris(Dufour) (Aranae, Lycosidae) y su comportamiento

    OpenAIRE

    Ortega Escobar, Joaquín

    1986-01-01

    Se describe el hábitat y los nidos de Lycosa fasciiventris DUFOUR (Araneae, lycosidae);asimismo se estudian algunos parámetros poblacionales de tres localizaciones: densidad, distan-cia entre nidos y proporción entre individuos adultos e individuos subadultos. Se estudia la correlación entre el tamaño de la araña y la profundidad y el diámetro delnido y se discute su relación con el comportamiento de la araña The habitat and nests of Lycosa fasciiventris DUFOUR (Araneae, Lycosidae) are ...

  10. Effects of energy content and energy density of pre-portioned entrées on energy intake

    OpenAIRE

    Blatt, Alexandria D.; Williams, Rachel A.; Roe, Liane S.; Rolls, Barbara J.

    2012-01-01

    Pre-portioned entrées are commonly consumed to help control portion size and limit energy intake. The influence of entrée characteristics on energy intake, however, has not been well studied. We determined how the effects of energy content and energy density (ED, kcal/g) of pre-portioned entrées combine to influence daily energy intake. In a crossover design, 68 non-dieting adults (28 men and 40 women) were provided with breakfast, lunch, and dinner on one day a week for four weeks. Each meal...

  11. Metamorfoses nas vanguardas: entre o homem e o animal

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    Kelvin Falcão Klein

    2011-08-01

    Full Text Available Este trabalho investiga a relação que se estabeleceu entre o homem e o animal no pensamento das vanguardas européias no início do século XX, principalmente o surrealismo, além de considerar uma parte de suas bases históricas e de suas sobrevivências na contemporaneidade. Partindo do caso de Édipo e da Esfinge, e das diferentes percepções críticas que gerou (desde Freud até Jacques Lacan e Giorgio Agamben, este trabalho reflete sobre as estratégias de afirmação do discurso da razão e da verdade na cultura ocidental, alcançando, com isso, o projeto de revistas de vanguarda como Acéphale e Minotaure. A categoria de metamorfose, na articulação com outros casos, é utilizada para considerar as implicações críticas do questionamento das fronteiras entre o homem e sua animalidade.

  12. Perspectivas quanto a negociações entre israelenses e palestinos

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    Heitor Figueiredo Sobral Torres

    2009-06-01

    Full Text Available Como a política externa norteamericana pode estimular novas dinâmicas nas negociações entre israelenses e palestinos.

  13. Maltrato por abuso de poder entre iguales en el alumnado con discapacidad

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    Cristina del Barrio

    2016-01-01

    Full Text Available Tras un repaso del conocimiento actual acerca del acoso y la exclusión social entre escolares, como problemas de grupo, se revisan los estudios que han explorado la naturaleza y las consecuencias de este tipo de relación con el alumnado con alguna discapacidad. De esta revisión, se deriva que la incidencia de víctimas es mayor comparada con la del alumnado sin discapacidad, y que el modo en que se manifiesta el abuso de poder entre iguales, así como el tipo de persona a quien se acude en busca de ayuda es diferente según el tipo de discapacidad, sea sensorial, motriz o del desarrollo (intelectual, del habla o comunicación, del espectro autista. El artículo presta especial atención a cómo afectan los abusos entre iguales al alumnado con trastornos del espectro autista y se presentan los tipos de intervención que, centrados en el grupo de pares, han mostrado su eficacia para cambiar el clima de relaciones del grupo.

  14. Genetic parameter and correlation estimates of processing traits in half-sib progenies of tropical-adapted carrot germplasm Parâmetros genéticos e correlações entre características para processamento em progênies de meios-irmãos de germoplasma de cenoura tropical

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    Jairo V Vieira

    2012-03-01

    Full Text Available The estimate of the genetic parameters associated with processing (fresh-cut traits, including root length (RL, is crucial for carrot breeding programs in tropical areas. The cultivar Alvorada is an important germplasm due to its resistance to nematodes, leaf blight, heat-tolerance, and high carotenoid content. Seventy-four 'Alvorada' half-sib progenies were evaluated during the summer of 2005 in the Federal District, Brazil, in a randomized complete block design with three replications. Thirteen competitive plants in each block were randomly selected and evaluated and/or classified for RL and for number of leaves (NL, leaf length (LL, root tip type (RT, root mass (RW, crown shape (CS, root diameter (RD, and xylem diameter (XD. The Pearson's correlation coefficients and the heritability values were estimated for all traits. The path analysis was also used considering the RL trait as dependent variable. The heritability for RL ranged from 12 to 44%. For the other traits, the values ranged from 3% (RD to 79% (LL. Phenotypic and genotypic correlations among all traits were low to intermediate. Path analysis indicated positive direct relationship between RL and RW, whereas RD and XD displayed negative direct effect on RL. Longer roots had narrow diameter and narrow XD. Recurrent selection based upon either half-sib or S1 families would be more effective than mass phenotypic recurrent selection in increasing RL and to develop populations expressing multiple desirable processing traits in tropical-adapted carrot germplasm.A estimativa de parâmetros genéticos associados com caracteres de processamento industrial, incluindo comprimento de raiz (RL, é crucial para programas de melhoramento de cenoura para áreas tropicais. A cultivar Alvorada é um importante germoplasma devido à sua resistência a nematóides e queima-das-folhas, tolerância ao calor e alto conteúdo de carotenóides. Setenta e quatro progênies meio-irmãs derivadas de 'Alvorada

  15. TINGKAT HIDUP DAN PERTUMBUHAN AVOKAD HASIL SAMBUNG PUCUK ENTRES YANG DISIMPAN DALAM PELEPAH BATANG PISANG

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    Lazarus Agus Sukamto

    2014-01-01

    Full Text Available Buah avokad mempunyai kandungan nutrisi yang sangat baik bagi masyarakat khususnya kandungan lemak tidak jenuh dan protein yang tertinggi bila dibandingkan jenis buah lain. Untuk tujuan komersial, tanaman avokad perlu diperbanyak secara vegetatif untuk memperoleh bibit yang telah terbukti kualitas dan kuantitas tinggi, serta berbuah lebih awal. Keberhasilan penyambungan sangat dipengaruhi oleh kesegaran entres. Penelitian ini bertujuan untuk mengetahui keberhasilan dan pertumbuhan sambungan tanaman avokad dengan menggunakan entres yang disimpan dalam pelepah batang pisang selama dua hingga sembilan hari. Parameter pengamatan meliputi persentase tingkat hidup sambungan, pertumbuhan panjang, jumlah daun, jumlah cabang, dan panjang percabangan batang atas setiap bulan sampai enam bulan. Data pertumbuhan dianalisis secara statistik dengan ANOVA dan uji lanjut Duncan. Lama penyimpanan entres berpengaruh terhadap tingkat hidup hasil sambungan dan pertumbuhan batang atas avokad. Rerata tingkat hidup bibit sambungan avokad terus menurun dari 99,5% pada umur satu bulan sampai 71% pada umur enam bulan setelah penyambungan, tetapi tidak mengalami penurunan setelah lima bulan penyambungan. Penyimpanan entres avokad dalam pelepah pisang dapat dipertahankan kesegarannya selama sembilan hari, yaitu tingkat hidup sambungan 60% - 84% enam bulan setelah penyambungan. Ada kecenderungan bahwa makin lama penyimpanan entres, makin menurun pertumbuhan batang atas avokad; sebaliknya makin lama umur penyambungan, makin meningkat pertumbuhan batang atas avokad, kecuali jumlah cabangnya yang relatif tidak meningkat setelah dua bulan penyambungan.

  16. A relação entre os modos adaptativos de ROY e a taxonomia de diagnósticos de enfermagem da NANDA La relación entre los modos adaptativos de ROY y la taxonomía de diagnósticos de enfermería de la NANDA The relationship among the adaptation modes of ROY and NANDA taxonomy of nursing diagnoses

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    Marcos Venícios de Oliveira Lopes

    1999-10-01

    Full Text Available Estudo teórico-reflexivo objetivando estabelecer uma correlação entre a taxonomia de diagnósticos da NANDA e os modos adaptativos propostos por Roy. Foram definidas as relações entre os indicadores de adaptação positiva, os problemas comuns de adaptação propostos por Roy e os diagnósticos de enfermagem da NANDA. Os resultados nos permitiram perceber uma forte correspondência entre os conceitos existentes no modelo teórico estudado e a taxonomia de diagnósticos de enfermagem da NANDA. Concluímos que existe a possibilidade de operacionalizar o uso dos diagnósticos de enfermagem da NANDA tendo como base o processo de enfermagem fundamentado na teoria da Adaptação de Roy.Estudio teórico-reflexivo buscando establecer una correlación entre los diagnósticos de enfermería de la NANDA y los modos adaptativos propuestos por Roy. Fueron definidas las relaciones entre los indicadores de adaptación positiva, los problemas comunes de adaptación propuestos por Roy y los diagnósticos de enfermería de la NANDA. Los resultados permitieron ver una correlación fuerte entre los conceptos existentes en el modelo teórico estudiado y la taxonomía de la NANDA de diagnósticos de enfermería. Nosotros concluimos que existe la posibilidad de operacionalizar el uso de los diagnósticos de enfermería de la NANDA teniendo como base el proceso de enfermería basado en la teoría de la Adaptación de Roy.The present study is theoretical-reflexive with the purpose to establish a correlation between NANDA's taxonomy diagnoses and the adaptation modes proposed by Roy. Authors defined the relationships among the indicators of positive adaptation, the common problems of adaptation proposed by Roy and NANDA's nursing diagnoses. Results showed a strong correspondence between the existent concepts in the studied theoretical model and NANDA's taxonomy of nursing diagnoses. Authors concluded that there is a possibility of using NANDA's nursing diagnoses and

  17. Prevalência do uso de drogas e desempenho escolar entre adolescentes

    Directory of Open Access Journals (Sweden)

    Beatriz Franck Tavares

    2001-04-01

    Full Text Available OBJETIVO: Avaliar a prevalência do uso de drogas entre adolescentes de escolas com segundo grau. MÉTODOS: Com base em um delineamento transversal, foi realizado estudo em 1998 , em Pelotas, RS. Um questionário anônimo, auto-aplicado em sala de aula, foi respondido por uma amostra proporcional de estudantes com idade entre 10 e 19 anos, matriculados no primeiro grau (a partir da 5ª série e no segundo grau, em todas as escolas públicas e particulares na zona urbana do município que tinham segundo grau. Realizou-se até três revisitas para aplicação aos alunos ausentes. RESULTADOS: Foram entrevistados 2.410 estudantes e o índice de perdas foi de 8%. As substâncias mais consumidas, alguma vez na vida, foram álcool (86,8%, tabaco (41,0%, maconha (13,9%, solventes (11,6%, ansiolíticos (8,0%, anfetamínicos (4,3% e cocaína (3,2%. Os meninos usaram mais do que as meninas maconha, solventes e cocaína, enquanto elas usaram mais ansiolíticos e anfetamínicos. Uso no mês, uso freqüente, uso pesado e intoxicações por álcool foram mais prevalentes entre os meninos. Após controle para fatores de confusão, permaneceu positiva a associação entre uso de drogas (exceto álcool e tabaco e turno escolar noturno, maior número de faltas à escola no mês anterior e maior número de reprovações escolares. CONCLUSÕES: A prevalência de experimentação de drogas em adolescentes escolares é alta, sendo importante detectar precocemente grupos de risco e desenvolver políticas de prevenção do abuso e dependência dessas substâncias.

  18. Relaciones entre el sueño y la adicción

    Science.gov (United States)

    Cañellas, Francesca; de Lecea, Luis

    2016-01-01

    Resumen La interacción entre los trastornos del sueño y el abuso de sustancias es ya conocida, pero seguramente más compleja de lo que se pensaba. Existe tanto una relación positiva entre tener un trastorno por uso de substancias y sufrir un trastorno de sueño, como viceversa. Los efectos sobre el sueño dependen de la substancia utilizada, pero se ha demostrado que tanto durante su uso como en período de abstinencia los consumidores tienen diferentes problemas de sueño y fundamentalmente un sueño más fragmentado. Sabemos que hay que tener en cuenta los problemas de sueño para evitar recaídas en la adicción. Investigaciones recientes indican que el sistema hipocretinérgico definido por el neuropéptido hipocretina/orexina (Hcrt/ox), localizado en el hipotálamo lateral e implicado entre otros en la regulación del ciclo sueño-vigilia, jugaría un papel importante en las conductas adictivas. Diferentes estudios han demostrado interacciones entre el sistema hipocretinérgico, los circuitos de respuesta aguda al estrés y los sistemas de recompensa. También sabemos que la activación optogenética selectiva del sistema hipocretinérgico incrementa la probabilidad de la transición del sueño a la vigilia, y también es suficiente para iniciar un comportamiento compulsivo de recaída adictiva. La activación del sistema hipocretinérgico podría explicar la hipervigilia asociada al estrés y a la adicción. El mayor conocimiento de esta interacción permitiría entender mejor los mecanismos de la adicción y encontrar nuevas estrategias para el tratamiento de las adicciones. PMID:23241715

  19. Prevalência do uso de drogas e desempenho escolar entre adolescentes

    Directory of Open Access Journals (Sweden)

    Tavares Beatriz Franck

    2001-01-01

    Full Text Available OBJETIVO: Avaliar a prevalência do uso de drogas entre adolescentes de escolas com segundo grau. MÉTODOS: Com base em um delineamento transversal, foi realizado estudo em 1998 , em Pelotas, RS. Um questionário anônimo, auto-aplicado em sala de aula, foi respondido por uma amostra proporcional de estudantes com idade entre 10 e 19 anos, matriculados no primeiro grau (a partir da 5ª série e no segundo grau, em todas as escolas públicas e particulares na zona urbana do município que tinham segundo grau. Realizou-se até três revisitas para aplicação aos alunos ausentes. RESULTADOS: Foram entrevistados 2.410 estudantes e o índice de perdas foi de 8%. As substâncias mais consumidas, alguma vez na vida, foram álcool (86,8%, tabaco (41,0%, maconha (13,9%, solventes (11,6%, ansiolíticos (8,0%, anfetamínicos (4,3% e cocaína (3,2%. Os meninos usaram mais do que as meninas maconha, solventes e cocaína, enquanto elas usaram mais ansiolíticos e anfetamínicos. Uso no mês, uso freqüente, uso pesado e intoxicações por álcool foram mais prevalentes entre os meninos. Após controle para fatores de confusão, permaneceu positiva a associação entre uso de drogas (exceto álcool e tabaco e turno escolar noturno, maior número de faltas à escola no mês anterior e maior número de reprovações escolares. CONCLUSÕES: A prevalência de experimentação de drogas em adolescentes escolares é alta, sendo importante detectar precocemente grupos de risco e desenvolver políticas de prevenção do abuso e dependência dessas substâncias.

  20. Relación entre obesidad y caries dental en niños

    Directory of Open Access Journals (Sweden)

    Farith Damián González Martínez

    Full Text Available El estado de salud bucal se ha relacionado con la presencia de algunas alteraciones sistémicas; en la población infantil se ha sugerido que la caries dental se asocia con la obesidad. El objetivo de esta revisión fue comparar los resultados de la evidencia sobre la relación entre obesidad y caries dental en niños, por lo cual se realizó una búsqueda computarizada y sistemática utilizando el término "dental caries" combinado con "obesity", "overweight" y "underweight" en las bases de datos Medline, Embase, Pubmed y Ovid, arrojando 439 artículos, de estos se seleccionaron 15 artículos que cumplieron con los criterios de inclusión y superaron una evaluación de calidad metodológica. Los hallazgos fueron almacenados y organizados en una base de datos, se procesaron y analizaron estadísticamente teniendo en cuenta razones de disparidad y el coeficiente de correlación de Pearson reportados. Se presentó un prevalencia general de caries dental de 49,6 %, para los obesos fue de 52,5 % y para los no obesos de 46,8 %. No se encontró asociación entre caries y obesidad en 9 de 15 estudios. La evidencia consultada sugiere que no existe relación entre obesidad y caries dental en niños, pues la prevalencia de caries no mostró diferencias estadísticamente significantes entre niños obesos y no obesos.

  1. Para tener entre manos una revista

    OpenAIRE

    Gabriel Giannone

    2017-01-01

    Consideramos importante rescatar el trabajo colectivo y acumulado que precede y sucede a la labor de intermediación académica que realiza una revista. Para ello recordamos una clásica frase prologal: el texto que usted tiene en sus manos. Con cierta ironía, porque quizás muy pocos de los lectores puedan tener entre manos y oler el papel impreso de Chasqui. Desde sus pantallas, sus tablets o sus teléfonos la intención es que se comprenda este número como un solo cuerpo. Y al mismo tiempo, como...

  2. El uso de drogas entre los estudiantes universitarios y su relación con el maltrato durante la niñez y la adolescencia

    OpenAIRE

    Gonzalez, Yolanda; Mann, Robert; Hamilton, Hayley; Erickson, Patricia; Sapag, Jaime; Brands, Bruna; Strike, Carol; Simich, Laura; Giesbrecht, Norman; Wright, Maria da Gloria Miotto; Cumsille, Francisco; Khenti, Akwatu

    2015-01-01

    Panamá, país de tránsito para productores y consumidores de drogas, generando economía emergente, cultura de violencia y maltrato en la familia y comunidad, siendo niños y adolescentes vulnerables al uso y abuso de drogas por exposición prolongada al maltrato. Se determina independencia o relación entre uso y abuso de droga con el maltrato durante la niñez y la adolescencia en estudiantes en una universidad en la ciudad de Panamá. Se aplicó el método cuantitativo, diseño transeccional, correl...

  3. Relação entre as habilidades auditivas no primeiro ano de vida e o diagnóstico de linguagem em prematuros

    Directory of Open Access Journals (Sweden)

    Cyntia Barbosa Laureano Luiz

    Full Text Available RESUMO Objetivo: verificar se há relação entre as habilidades auditivas no primeiro ano de vida e o diagnóstico de linguagem entre os 2 e 4 anos de idade em crianças nascidas pré-termo com peso abaixo de 2000 gramas. Métodos: foram selecionados um grupo de 54 crianças com emissões otoacústicas evocadas por estímulos transientes presentes nos primeiros três meses, com avaliação audiológica comportamental entre os 6 e 18 meses e avaliação de linguagem entre os 2 e 4 anos de idade. Resultados: não foram observadas diferenças estatisticamente significantes entre a ocorrência de reflexo cócleo palpebral e a habilidade de localização sonora entre 6 e 18 meses com resultado da avaliação de linguagem.Em relação à habilidade de reconhecimento de ordens verbais entre os 12 e 18 meses foi observada diferença estatisticamente significante.Crianças que apresentam reconhecimento de ordens verbais alterado entre 12 e 18 meses tem 12,25 vezes mais chances de apresentar linguagem alterada entre os 2 e 4 anos. Conclusão: existe uma relação entre o reconhecimento de ordens verbais alterado entre 12 e 18 meses e a alteração no resultado da avaliação de linguagem entre os 2 e 4 anos.

  4. Cobalt catalysts for the conversion of methanol and for Fischer-tropsch synthesis to produce hydrocarbons

    International Nuclear Information System (INIS)

    Mauldin, C.H.; Davis, S.M.; Arcuri, K.B.

    1987-01-01

    A regeneration stable catalyst is described for the conversion at reaction conditions of methanol or synthesis gas to liquid hydrocarbons which consists essentially of from about 2 percent to about 25 percent cobalt, based on the weight of the catalyst composition, composited with titania, or a titania-containing support, to which is added sufficient of a zirconium, hafnium, cerium, or uranium promoter to provide a weight ratio of the zirconium, hafnium, cerium, or uranium metal:cobalt greater than about 0.101:1

  5. Application of energy-dispersive XRF technique in the hydrometallurgy study of local zircon

    International Nuclear Information System (INIS)

    Meor Yusoff Sulaiman; Kamaruddin Hussin; Azizan Aziz

    1996-01-01

    In this study, energy-dispersive X-ray Fluorescence (EDXR-F) was used to analyse the elemental composition of the starting zircon mineral associated elements in the leaching solution. Besides analysing the major elements i.e. of zirconium, silicon and hafnium, trace elemental analysis for iron, titanium and the naturally occurring radioactive element thorium and uranium are important in establishing the grades of Malaysian zircon. The technique was also used in determine the optimum conditions for zirconium and hafnium recovery during the leaching process

  6. Preferência musical e busca de sensações entre jovens

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Pimentel

    Full Text Available Este estudo objetivou conhecer a correlação entre preferência musical e busca de sensações, testando modelos de mediação e moderação. Participaram 279 estudantes do ensino médio, com média de idade de 17 anos e igualmente distribuídos por sexo, que responderam a Escala de Preferência Musical, o Inventário de Arnett de Busca de Sensações e questões demográficas. Observou-se correlação da preferência por estilos musicais alternativos (positiva, como, por exemplo, rock, música eletrônica e convencional (negativa, como, por exemplo, música clássica, música religiosa com o fator intensidade de busca de sensações. Constatou-se também que as relações entre o fator novidade e os estilos alternativos e convencionais foram mediadas pela busca por intensidade. Testou-se a moderação da busca por novidade na relação entre intensidade e música alternativa, que não foi confirmada. Tais resultados foram discutidos com base na literatura sobre correlatos da busca de sensações, e sugere-se estudos que contribuam para entender seu efeito na preferência musical.

  7. Conflictos entre derechos constitucionales y maneras de resolverlos

    Directory of Open Access Journals (Sweden)

    Moreso, José Juan

    2010-10-01

    Full Text Available This paper deals with the question of the conflict of constitutional rights which acknowledge basic rights. It is shown that there are two extreme accounts: the subsumptive approach and the particularist approach that embody two main conceptions of practical rationality. Between both approaches there is room for a range of options. Two of them are taken into account: the proportionalist approach, which conserves the scope of rights restricting their stringency, and it is argued in favour of the specificationist approach, which preserve the stringency of rights restricting their scope.

    En este trabajo se analiza la cuestión de la colisión entre principios constitucionales que reconocen derechos básicos. Se muestra que hay dos posiciones extremas: el enfoque subsuntivo y el enfoque particularista, que encarnan dos grandes concepciones de la racionalidad práctica. Entre ambos enfoques hay lugar para un amplio espectro de opciones. Se toman dos en cuenta: el enfoque proporcionalista, que conserva el alcance de los derechos restringiendo su fuerza y el enfoque especificacionista, a favor del cual se argumenta, que conserva la fuerza de los derechos restringiendo su alcance.

  8. A floresta geométrica de Paul Claudel: fronteira entre dois mundos.

    Directory of Open Access Journals (Sweden)

    Vera Beatriz Siqueira

    Full Text Available resumo O artigo parte da análise do balé O homem e seu desejo, criado por Paul Claudel (poema plástico, Darius Milhaud (música e Audrey Parr (cenografia e figurino quando estavam no Rio de Janeiro entre 1917 e 1918. A ideia básica é pensar essa obra como parte integrante dos diálogos interculturais que fundam a modernidade global do início do século XX, investigando o papel desempenhado pela cultura e pela natureza brasileira no projeto de Claudel de articulação entre vanguarda, classicismo e primitivismo.

  9. La formación de la pareja entre marroquíes en España

    Directory of Open Access Journals (Sweden)

    Albert Esteve Palós

    2013-12-01

    Full Text Available El objetivo de este trabajo es examinar las pautas de formación de la pareja del colectivo marroquí en España. En concreto, se exploran los factores asociados con el hecho de tener y/o residir con la pareja en el mismo hogar y, entre los que tienen pareja, los factores relacionados con tener un cónyuge o pareja de un colectivo distinto al marroquí (exogamia. Se han utilizado datos de la muestra de microdatos del Censo de 2001 (n = 8.934 y utilizado modelos de regresión logística multinivel para variables de respuesta binaria. Entre las variables independientes se han incluido como variables contextuales el tamaño del grupo y la relación de masculinidad y como variables individuales la antigüedad en España y el nivel de instrucción. Los resultados muestran que las características del mercado matrimonial tienen una influencia escasa sobre el comportamiento de los marroquíes en España, especialmente entre los hombres. Esto sugiere el carácter binacional (Marruecos-España de su mercado matrimonial. Entre las variables individuales, la antigüedad y el nivel de instrucción están asociados positivamente con una mayor exogamia para los hombres y las mujeres. Un mayor nivel de educación aumenta las posibilidades de convivir con la pareja en España entre los hombres y las reduce entre las mujeres. Las mujeres con estudios universitarios rompen con el perfil tradicional de la mujer marroquí en España, mayoritariamente asociado a una migración de tipo familiar

  10. Apoio social e saúde entre idosos

    Directory of Open Access Journals (Sweden)

    Ramos Marília P.

    2002-01-01

    Full Text Available O presente artigo trata da relação entre a saúde dos idosos e relacionamentos sociais, bem como na interpretação e entendimento desta problemática sob a luz de dois enfoques teóricos: um macro, centrado na Teoria da Integração Social de Emile Durkheim e outro micro, centrado na Teoria das Trocas, de Peter Blau, com ênfase na Teoria da Eqüidade. A integração social (freqüência de contatos pode ter efeitos negativos na saúde, mas isto tem de ser medido pela qualidade dos contatos. Algumas conclusões apresentadas indicam que as relações sociais têm um efeito na saúde, no sentido de que as pessoas, nas sociedades modernas, esperam a reciprocidade, e, quando isto não é possível, principalmente na fase do envelhecimento, as pessoas sentem-se dependentes, e isso pode afetar a saúde de diferentes maneiras. Por outro lado, quando as pessoas têm problemas de saúde, elas experienciam uma falta de relações sociais balanceadas devido à incapacidade para trocar em bases iguais. Sendo assim, conclui-se que a relação entre relações sociais e saúde na população idosa pode ser uma relação recíproca.

  11. Associação entre a analgesia epidural e o trauma perineal no parto vaginal Asociación entre la analgesia epidural y el trauma perineal en el parto vaginal Association between epidural analgesia and perineal laceration in vaginal delivery

    Directory of Open Access Journals (Sweden)

    Juliana Cristina dos Santos Monteiro

    2009-03-01

    Full Text Available O objetivo deste estudo foi analisar a associação entre a analgesia epidural e a laceração perineal em mulheres submetidas ao parto vaginal. Foi realizado um estudo descritivo e transversal, para o qual foram pesquisados 109 prontuários de mulheres assistidas durante o processo de parturição, em uma maternidade em Ribeirão Preto. Os dados foram coletados nos meses de março e abril de 2003. Para analisar a correlação entre as variáveis foi aplicado o teste qui-quadrado. Foi realizado parto normal em 91,7% (100 das parturientes e fórceps em 8,2% (9. Na análise dos dados, 74,3% da amostra receberam analgesia epidural; destas, 26,5% tiveram algum grau de laceração perineal e 9,1%, períneo íntegro, não sendo possível verificar a associação entre as variáveis mencionadas. Não foi verificada, neste estudo, significância estatística para afirmar que as condições do períneo após o parto vaginal e a utilização da analgesia epidural estão associadas (valor x²4GL= 3,1.El objetivo de esto estudio fue analizar la asociación entre la analgesia epidural y la laceración perineal en mujeres sometidas al parto vaginal. Fue realizado un estudio descriptivo y transversal, para lo cual fueron investigados 109 prontuarios de mujeres asistidas durante el proceso de parturición en una maternidad en Ribeirão Preto. Los datos fueron colectados en marzo y abril de 2003. Para analizar la correlación entre las variables fue aplicado el Teste Chi-Cuadrado. Fue realizado parto normal en 91,7% (100 de las parturientes y en 8,2% (09 parto fórceps. En el análisis de los datos, 74,3% de la muestra recibieron analgesia epidural, y de estas 26,5% tuvieron algún nivel de laceración perineal y 9,1% perineo íntegro. No fue posible verificar la asociación entre las variables aludidas. No fue verificado en esto estudio, significancia estadística para afirmar que las condiciones del perineo después del parto vaginal y el uso de analgesia

  12. Relação entre escores de desempenho motor e aptidão física em crianças com idades entre 07 e 08 anos

    OpenAIRE

    Krebs, Ruy Jornada; Duarte, Marcelo Gonçalves; Nobre, Glauber Carvalho; Nazario, Patrik Felipe; Santos, João Otacílio Libardoni dos

    2011-01-01

    Existem muitas sugestões de testes que se propõem a avaliar o desempenho motor e a aptidão física. Estes testes levam em consideração diferentes critérios para análise do desempenho como formas e padrões de movimento, tempo, distância e repetições em cada tarefa. O objetivo deste estudo foi investigar a relação entre os escores de desempenho motor e aptidão física de crianças. Participaram deste estudo, 50 crianças (25 meninos e 25 meninas) com idades entre 7 e 8 anos e de ambos os sexos. O T...

  13. Relação entre o investimento social corporativo e o valor das empresas brasileiras

    Directory of Open Access Journals (Sweden)

    Annor da Silva Junior

    2010-08-01

    Full Text Available Este estudo tem por objetivo investigar a existência de relação entre os investimentos sociais corporativos e o valor das empresas listadas na Bolsa de Valores de São Paulo (Bovespa e que publicam balanço social no Instituto Brasileiro de Análises Sociais e Econômicas (Ibase, mais especificamente, identificando se empresas que investem sistematicamente em responsabilidade social têm seu valor potencializado ou diminuído. Os resultados encontrados não evidenciaram que investimentos em práticas de responsabilidade social acarretam um melhor ou pior desempenho no valor de mercado das empresas. Encontrou-se relação não significativa entre a variável de controle tamanho da empresa e o q de Tobin em empresas com investimentos sociais corporativos. Encontrou-se relação negativa entre alguns setores de mercado e o valor das empresas representados pelo q de Tobin. Foi confirmado por esta pesquisa a relação positiva entre o tamanho das empresas e o valor dos investimentos sociais corporativos.

  14. La disciplina entre las disposiciones legales y los actores escolares

    Directory of Open Access Journals (Sweden)

    Nancy Palacios Mena

    2013-01-01

    Full Text Available Este artículo presenta una descripción del funcionamiento de la disciplina escolar en una institución educativa de secundaria en Colombia. Tiene como objetivo explicar el origen del conflicto disciplinario, las situaciones que lo generan, la forma como la institución trata de lograr y mantener la disciplina, las explicaciones que cada uno de los actores da a las situaciones conflictivas y la manera como son vividas por ellos. El diseño metodológico de la investigación combinó una encuesta, entrevistas y el análisis de documentos de la institución educativa. El análisis de los datos se hace a la luz de planteamientos sociológicos que reconocen la enorme importancia que ejercen las estructuras sociales sobre la forma de pensar y actuar de los individuos, pero también resaltan la gran capacidad de los actores sociales para amoldarse a dichas estructuras y a través de sus ideas y acciones darle una dinámica propia al tipo de relaciones que establecen entre individuos en sus entornos de vida más inmediatos. Se pudo concluir que sobre la disciplina escolar no hay unidad de criterio entre los docentes, los directivos y los estudiantes, ni en su definición, ni en su importancia, ni en los medios para conseguirla; dichas diferencias producen tensiones y desacuerdos entre los miembros de la comunidad educativa.

  15. Benign childhood epilepsy with centro-temporal spikes: correlation between clinical, cognitive and EEG aspects Epilepsia benigna da infância com pontas centrotemporais: correlação entre aspectos clínicos, eletrencefalográficos e cognitivos

    Directory of Open Access Journals (Sweden)

    Lineu Corrêa Fonseca

    2007-09-01

    Full Text Available Benign childhood epilepsy with centro-temporal spikes (BECTS is a form of epilepsy with no demonstrable anatomical lesion showing spontaneous seizure remission. During the active phase of the disease the children may show cognitive deficits. The objective of this study was to assess, in children with BECTS, the relationship between clinical-EEG aspects and performance in the school performance test (SPT, Raven's progressive matrixes test and the Wechsler Intelligence Scale for Children (WISC-III. Forty-two 7 to 11 year old children were included and the following tests carried out: anamnesis, neurological examination, electroencephalogram (EEG, SPT, Raven's test and WISC-III. The children with BECTS had normal IQ values but showed inferior performance in the SPT more frequently than "healthy" children, paired with respect to age and maternal scholastic level. There was moderate positive correlation between WISC-III results and the age when the seizures started and the educational level of the parents. On the other hand, aspects linked to the epileptic nature of BECTS, such as the number of seizures, time since last seizure and the number and lateralization of the centro-temporal spikes on the EEG, showed no correlation with the neuropsychological tests.A epilepsia benigna da infância com pontas centrotemporais (EBICT é uma forma de epilepsia na qual não existem lesões anatômicas demonstráveis e há remissão espontânea das crises. Na fase ativa da epilepsia as crianças podem apresentar déficits cognitivos. O objetivo deste estudo foi avaliar, em crianças com EBICT, a relação entre aspectos clínico-eletrencefalográficos e o desempenho no teste de desempenho escolar (TDE, no teste das matrizes progressivas de Raven e na Escala Wechsler de Inteligência para Crianças (WISC-III. Foram incluídas 42 crianças de 7 a 11 anos de idade. Foram realizados: anamnese, exame neurológico, eletrencefalograma (EEG, TDE, teste de Raven e WISC

  16. La telecol.laboració en la classe de llengua extranjera entre grups heterogenis d’estudiants

    Directory of Open Access Journals (Sweden)

    Mercedes López Santiago

    2014-06-01

    Full Text Available En l'ensenyament de llengües estrangeres, nombrosos professors treballen les competències lingüístiques i comunicatives mitjançant d'activitats que inclouen les TIC. Entre algunes, es troben els projectes de telecol·laboració per Internet, intercanvis asincrònics i sincrònics entre grups d'estudiants que pertanyen a diferents comunitats lingüístiques allunyades geogràficament. El nostre objectiu ha consistit a comprovar si un projecte de telecol·laboració sincrònic entre grups heterogenis d'estudiants, és factible i si contribueix al desenvolupament de les competències comunicatives, interculturals i tecnològiques.

  17. Asociación entre los turnos de noche y el cáncer de ovarios

    OpenAIRE

    Martín González, Elena

    2015-01-01

    OBJETIVO: Evaluar la asociación entre trabajar en turno de noche y la aparición de cáncer de ovario en las mujeres de España. DISEÑO: estudio de casos y controles. SUJETOS DE ESTUDIO: Casos: 658 mujeres de 35-74 años con diagnóstico de cáncer de ovario incidente entre los años 2008-2013 en España. Controles: 658 mujeres de 35-74 años con al menos un ovario y sin diagnóstico de cáncer de ovario incidente, ni trastornos nerviosos, del sueño o gastrointestinales entre los años 2008-2013 en...

  18. Du rapport entre le harcèlement et l’hégémonie intellectuelle

    OpenAIRE

    Berger, Vincent

    2015-01-01

    Mesdames, Messieurs, Chers collègues, Je suis très heureux que mon tout dernier discours ici à la Présidence de Paris Diderot – la fin même de cette intervention sera l’occasion pour moi de prononcer mes derniers mots de Président – le soit sur le thème des relations entre les hommes et les femmes à l’Université. Vous êtes ici dans  un  lieu  universitaire  engagé  sur  la  thématique de l’égalité entre les femmes et les hommes. Le harcèlement entre personnels me semble  un  problème  relat...

  19. Estimativas de correlações fenotípicas, genotípicas e de ambiente entre sete caracteres morfoagronômicos em oito acessos de moranga Estimates of phenotypic, genotypic and environment correlations among seven morphological and agricultural traits in eight pumpkin access

    Directory of Open Access Journals (Sweden)

    Antonio T. Amaral Júnior

    1994-01-01

    Full Text Available Sete caracteres morfoagronômicos, avaliados em oito acessos de moranga (Cucurbita maxima Duchesne foram submetidos à análise de correlações fenotípicas, genotípicas e de ambiente. As correlações genotípicas foram superiores às fenotípicas e de ambiente, indicando moderada influência deste último na expressão dos caracteres. Todos os pares de caracteres apresentaram correlações genotípicas positivas (> 0,75, evidenciando que a seleção para aumento na média de um caráter provocará alterações na média do outro, no mesmo sentido. Os caracteres comprimento da rama principal até a primeira flor feminina (RAMA F e o comprimento da rama principal até o ápice (RAMA T apresentaram a maior correlação genotípica, enquanto a menor magnitude dessa correlação ocorreu entre o número de nós da rama principal até a primeira flor feminina (NS F e o comprimento médio do internódio da rama principal até o ápice (COMP T.Seven morphological and agricultural traits were analysed in eight access of pumpkin (Cucurbita maxima Duchesne. They were subjected to a phenotypic, genotypic and environment correlations analysis. The genotypic estimates showed botter correlation results than the phenotypic and environmental estimates. Also indicated a moderated influence by the environment in the trait expression. All pairs of traits showed positive genotypic correlation (>0.75 with evidences that the selection aims the increase of traits average, and also it leads to an alteration in the average of the other traits in the same amount. The RAMA F traits (the lenght of the stem until the first female flower and RAMA T (the lenght of the stem until the top showed the highest genotypic correlation, while the minor magnitude in this correlation occurred between NS F (number of nodes in the stem until the first female flower and COMP T (the median lenght of stem's internodes until the top.

  20. Em busca de uma compreensão das relações entre família escola

    Directory of Open Access Journals (Sweden)

    Ana da Costa Polonia

    Full Text Available Pesquisadores e educadores têm mostrado um crescente interesse pelo estudo das relações entre a família e a escola devido à sua importância para a educação e o desenvolvimento humano. Neste artigo teórico, apresentamos algumas reflexões sobre o envolvimento da família com a escola e seu impacto sobre a aprendizagem e o desenvolvimento do aluno. Os benefícios de uma boa integração e as implicações de uma falta de integração entre os dois contextos são discutidos brevemente, bem como são descritos aspectos das relações estabelecidas entre ambos, que vêm sendo focalizados nas pesquisas empíricas. Especial atenção é dada às concepções e tipos de envolvimento família-escola e às percepções de pais e professores sobre este envolvimento. Ao final, enfatizamos a necessidade de uma integração mais efetiva entre a família e a escola, respeitando as peculiaridades de cada segmento, e da implementação de pesquisas que levem em conta as inter-relações entre os dois contextos.