Search Results - (Author, Cooperation:P. Souza)

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  1. 1
    Staff View
    Publication Date:
    2018-04-12
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Electronic ISSN:
    2375-2548
    Topics:
    Natural Sciences in General
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Staff View
    Publication Date:
    2018-02-26
    Publisher:
    Wiley-Blackwell
    Electronic ISSN:
    2045-7758
    Topics:
    Biology
    Published by:
    http://www.wiley.com/wiley-blackwell

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    H. ter Steege ; N. C. Pitman ; D. Sabatier ; C. Baraloto ; R. P. Salomao ; J. E. Guevara ; O. L. Phillips ; C. V. Castilho ; W. E. Magnusson ; J. F. Molino ; A. Monteagudo ; P. Nunez Vargas ; J. C. Montero ; T. R. Feldpausch ; E. N. Coronado ; T. J. Killeen ; B. Mostacedo ; R. Vasquez ; R. L. Assis ; J. Terborgh ; F. Wittmann ; A. Andrade ; W. F. Laurance ; S. G. Laurance ; B. S. Marimon ; B. H. Marimon, Jr. ; I. C. Guimaraes Vieira ; I. L. Amaral ; R. Brienen ; H. Castellanos ; D. Cardenas Lopez ; J. F. Duivenvoorden ; H. F. Mogollon ; F. D. Matos ; N. Davila ; R. Garcia-Villacorta ; P. R. Stevenson Diaz ; F. Costa ; T. Emilio ; C. Levis ; J. Schietti ; P. Souza ; A. Alonso ; F. Dallmeier ; A. J. Montoya ; M. T. Fernandez Piedade ; A. Araujo-Murakami ; L. Arroyo ; R. Gribel ; P. V. Fine ; C. A. Peres ; M. Toledo ; C. G. Aymard ; T. R. Baker ; C. Ceron ; J. Engel ; T. W. Henkel ; P. Maas ; P. Petronelli ; J. Stropp ; C. E. Zartman ; D. Daly ; D. Neill ; M. Silveira ; M. R. Paredes ; J. Chave ; A. Lima Filho Dde ; P. M. Jorgensen ; A. Fuentes ; J. Schongart ; F. Cornejo Valverde ; A. Di Fiore ; E. M. Jimenez ; M. C. Penuela Mora ; J. F. Phillips ; G. Rivas ; T. R. van Andel ; P. von Hildebrand ; B. Hoffman ; E. L. Zent ; Y. Malhi ; A. Prieto ; A. Rudas ; A. R. Ruschell ; N. Silva ; V. Vos ; S. Zent ; A. A. Oliveira ; A. C. Schutz ; T. Gonzales ; M. Trindade Nascimento ; H. Ramirez-Angulo ; R. Sierra ; M. Tirado ; M. N. Umana Medina ; G. van der Heijden ; C. I. Vela ; E. Vilanova Torre ; C. Vriesendorp ; O. Wang ; K. R. Young ; C. Baider ; H. Balslev ; C. Ferreira ; I. Mesones ; A. Torres-Lezama ; L. E. Urrego Giraldo ; R. Zagt ; M. N. Alexiades ; L. Hernandez ; I. Huamantupa-Chuquimaco ; W. Milliken ; W. Palacios Cuenca ; D. Pauletto ; E. Valderrama Sandoval ; L. Valenzuela Gamarra ; K. G. Dexter ; K. Feeley ; G. Lopez-Gonzalez ; M. R. Silman
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-10-19
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    *Biodiversity ; Models, Biological ; Population ; *Rivers ; South America ; Trees/*classification/*physiology
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Staff View
    ISSN:
    1435-1536
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents:
    Zusammenfassung In dieser Arbeit werden elektronenmikroskopisch die morphologischen Eigenschaften von Gelen aus Aluminiumhydroxyd und Aluminiumoxydmonohydrat Böhmit untersucht und die Änderungen verfolgt, die bei Zimmertemperatur beim Altern von C-alpha-Gel, hergestellt aus Ammoniumalaun, eintreten. Es werden Betrachtungen über den Alterungsmechanismus und die Bildung sogenannter Somatoide (Bezeichnung von Kohlschütter) angestellt.
    Notes:
    Summary (abstract) This paper describes the electron microscope morphology of gels of aluminium hydroxide and of aluminium oxide monohydrate Böhmite and the transformations which occur at room temperature during the aging of C-alpha gel prepared from ammonium alum. A mechanism for the morphological transformations during the aging of C-alpha gel and for the formation of somatoids is suggested.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01513437

    Articles: DFG German National Licenses
  5. 5
    Staff View
    ISSN:
    1435-1536
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Chemistry and Pharmacology
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes:
    Summary Gels and sols of aluminum oxide trihydrate were prepared by five different methods and studied by x-ray diffraction and electron microscopy. The x-ray diffraction analysis has shown that all methods produce mixtures of Gibbsite and Bayerite, the relative proportions of each varying from method to method. A sol and gel prepared by the same method present identical x-ray diffraction patterns and their morphologies are similar in the electron microscope. Two main particle shapes were observed: hexagonal prisms and triangular somatoids. There is experimental evidence which indicates that the former are Gibbsite and the latter, Bayerite. On this basis Willstaetter's methods seem to produce more Bayerite than Gibbsite. The reverse was true for Kraut's method, while in Fricke and Jockers' method, almost pure Bayerite was produced. A platelet structure is proposed for the triangular somatoids.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01510493

    Articles: DFG German National Licenses
  6. 6
    Santos, H. Souza ; Kiyohara, P. K. ; Santos, P. Souza
    Springer
    Published 2000
    Staff View
    ISSN:
    1573-4811
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1023/A:1006708602621

    Articles: DFG German National Licenses
  7. 7
    Souza, P. L. ; Rao, E. V. K. ; Alexandre, F.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A photoluminescence emission attributed to (SiAs-VAs) at 1.77 eV at 77 K has been previously observed in annealed Si-doped Al0.3Ga0.7As layers grown by molecular beam epitaxy at 680 °C. An emission with similar characteristics has now been observed in as-grown samples fabricated at lower temperatures. New results render the attribution of the deep PL emission to the pair (SiIII-SiAs) more likely. The possibility of a heat treatment producing the same defect as a low-temperature molecular beam epitaxy growth is also discussed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.351716

    Articles: DFG German National Licenses
  8. 8
    Tribuzy, C. V. B. ; Butendeich, R. ; Pires, M. P. ; Souza, P. L.

    [S.l.] : American Institute of Physics (AIP)
    Published 2001
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Good-optical-quality C delta-doped AlGaAs layers grown by metalorganic vapor phase epitaxy using CBr4 with the impurities confined over not more than 5 Å and with doping levels above 1×1012 cm−2 are obtained. Such layers are found to be adequate for use in the fabrication of nipi superlattices for amplitude modulation. Yet, little flexibility is found in the growth conditions, in particular for the V to III fluxes ratio, for obtaining such layers. © 2001 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1382826

    Articles: DFG German National Licenses
  9. 9
    Souza, P. L. ; Ribas, P. R. ; Bellini, J. V. ; Mendes, W. M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Different InP samples were exposed to electron and γ radiation at 300 and 77 K, respectively. The effects of the exposure to high energy radiation were investigated by photoluminescence. A major reduction in the photoluminescence signal from all samples was observed due to the defects introduced. In the case of γ-irradiated samples, the photoluminescence characteristics were recovered after room temperature aging while for the electron irradiated ones a heat treatment either at 473 or 673 K was required for annealing out the radiation-induced defects. The different roles played by the amphoteric dopant Sn and the n dopant S in the changes in the photoluminescence near band-edge spectra are addressed. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.361397

    Articles: DFG German National Licenses
  10. 10
    Souza, P. L. ; Yavich, B. ; Pamplona-Pires, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1997
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A series of periodically Si δ-doped InP samples with 5 and 10 periods varying from 92 to 278 Å has been investigated in terms of the transport and optical properties. A reduction in mobility with decreasing period was observed due to the increasing overlap of the electronic wavefunction with the various Si planes. A broad band emission was detected for the periodic structures at energies higher than the InP band gap. The cutoff energy for this band decreases with the period and this behavior can be described by a d−2/3 decay. The results are discussed and compared with the ones for GaAs available in the literature. © 1997 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.365946

    Articles: DFG German National Licenses
  11. 11
    Souza, P. ; Rao, E. V. K. ; Alexandre, F. ; Gauneau, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1988
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Luminescence spectra of variously silicon-doped Al0.3Ga0.7As (Al0.3Ga0.7As@B: Si) single layers grown by molecular-beam epitaxy were investigated as a function of silicon effusion-cell temperature. A correlation between silicon incorporation as a complex involving SiAs and the existence of a deep broadband emission is suggested. To achieve this, in addition to photoluminescence, Hall effect, capacitance, and secondary ion mass spectroscopy measurements were also performed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.341216

    Articles: DFG German National Licenses
  12. 12
    Pamplona Pires, M. ; Souza, P. L. ; von der Weid, J. P.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1994
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We present a new versatile and simple pump-and-probe technique to measure the change in reflectivity (ΔR) and to time resolve the signal in a time scale faster than the responsivity of the detector used. Also, by slightly changing the experimental conditions, decay times ranging from 0.2 ns to 0.1 ms can be measured. This technique presents the advantage of eliminating in a natural way any undesirable photoluminescence or background signal. Important parameters for carrier dynamics studies are extracted from the time-resolved signal obtained. In addition, no contribution to the change in reflectivity due to band-filling effects was observed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.113084

    Articles: DFG German National Licenses
  13. 13
    Köck, A. ; Freisleben, S. ; Gmachl, C. ; Gornik, E. ; Rosenberger, M. ; Korte, L. ; de Souza, P. L.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We demonstrate a novel concept for a mode selection mechanism in surface emitting laser diodes. This concept is based on a strong coupling process between the laser mode and a surface mode on top of the laser diode. The mode selection mechanism is the result of a strong feedback from the surface mode into the laser diode. Nearly single-modelike emission spectra are achieved from surface emitting GaAs/AlGaAs laser diodes and qualitatively explained by a model based on ray optics. The main advantage of this type of laser diode is its simple fabrication and the possibility of adjusting the desired wavelength independent of the growth process by external technological parameters. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.114533

    Articles: DFG German National Licenses
  14. 14
    Pamplona Pires, M. ; Yavich, B. ; Souza, P. L.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1999
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We study the dependence of the chirp parameter on heavy- and light-hole energy splitting by analyzing the change in the absorption curve of different InGaAs/InAlAs p-i-n multiple quantum well structures designed for use in amplitude modulators. We observe, for the transverse electric mode, a high chirp parameter for the sample whose fundamental transition involves the light hole, whereas for samples whose fundamental transition involves the heavy hole, the more polarization sensitive the samples are, the smaller the chirp parameter is. This indicates that it is not possible to have tensile strained InGaAs/InAlAs multiple quantum well structures for electro-absorptive modulators which are simultaneously chirp-free and polarization independent. © 1999 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.124345

    Articles: DFG German National Licenses
  15. 15
    Cutress, T. W. ; Hunter, P. B. V. ; Beck, D. J. ; Souza, P.

    Oxford, UK : Blackwell Publishing Ltd
    Published 1978
    Staff View
    ISSN:
    1600-0528
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Notes:
    Abstract Examination of 2,138 subjects, aged 15–65+ years, was carried out by calibrated examiners using mirrors and fibre optic illumination. Each subject was scored by the Periodontal Status Index, PSI (WHO Oral Health Surveys), Periodontal Index, PI (Russell) and the Oral Hygiene Index, OHI (Greene & Vermillion). For the PSI, PI and OHI all scores were age-dependent with the exception of soft deposits in PSI and OHI, which were age-independent. The advantages of the PSI system were considered to be the ease of scoring and the opportunity to assess treatment requirements, in terms of time, at the public health service level. Disadvantages were lack of quantitation, difficulties of diagnosis of intense gingivitis, and localized and general conditions. The PI and OHI systems provided a more objective, quantitative and sensitive basis of scoring than the PSI. Statistical tests showed that respective indices are associated and measuring the same kind of criteria. Examiner calibration and consistency were similar for both scoring systems.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1111/j.1600-0528.1978.tb01159.x

    Articles: DFG German National Licenses
  16. 16
    Souza, P. L. ; Rao, E. V. K.

    [S.l.] : American Institute of Physics (AIP)
    Published 1990
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A detailed photoluminescence study of a deep broadband emission as a function of the dopant concentration is conducted in molecular-beam epitaxy-grown silicon-doped Al0.3Ga0.7As single layers. The deep broadband which is correlated to the Si concentration consists of several emissions among which three are suggested to be due to different Si complexes. The effects of annealing the samples contributed immensely to this investigation. A model to explain the direct and indirect participations of SiAs in the formation of Si complexes during heat treatment is proposed. The photoluminescence is complemented by the Hall-effect, capacitance, and secondary-ion-mass spectroscopy measurements.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.345047

    Articles: DFG German National Licenses
  17. 17
    Staff View
    ISSN:
    0021-9614
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0021-9614(89)90129-8

    Articles: DFG German National Licenses
  18. 18
    Souza, P. ; Rao, E.V.K.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0038-1098
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0038-1098(88)90457-7

    Articles: DFG German National Licenses
  19. 19
    de Souza, P. ; Houghton, P.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0305-4403
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Archaeology
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0305-4403(77)90063-2

    Articles: DFG German National Licenses
  20. 20
    Souza, P. ; Paz-Andrade, M.I. ; Pilcher, G.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0040-6031
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0040-6031(91)85246-E

    Articles: DFG German National Licenses