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325 results on '"Sousa, J. C."'

2. Size-dependent bandgap and particle size distribution of colloidal semiconductor nanocrystals

Author

Ferreira, Diego Lourençoni, Sousa, J. C. L., Maronesi, R. N., Bettini, J., Schiavon, M. A., Teixeira, Alvaro V. N. C., and Silva, Andreza G.

Subjects
Condensed Matter - Materials Science
Abstract

A new analytical expression for the size-dependent bandgap of colloidal semiconductor nanocrystals is proposed within the framework of the finite-depth square-well effective mass approximation in order to provide a quantitative description of the quantum confinement effect. This allows one to convert optical spectroscopic data (photoluminescence spectrum and absorbance edge) into accurate estimates for the particle size distributions of colloidal systems even if the traditional effective mass model is expected to fail, which occurs typically for very small particles belonging to the so-called strong confinement limit. By applying the reported theoretical methodologies to CdTe nanocrystals synthesized through wet chemical routes, size distributions are inferred and compared directly to those obtained from atomic force microscopy and transmission electron microscopy. This analysis can be used as a complementary tool for the characterization of nanocrystal samples of many other systems such as the II-VI and III-V semiconductor materials., Comment: 9 pages, 5 figures

Published
2017
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3. (063) Effect of Phosphodiesterase Type 4 Inhibitor on Erectile Function Recovery and Nerve Regeneration After Cavernous Nerve Injury in Rats

Author

Linhares, B L, primary, Miranda, E P, additional, Campos, R M, additional, Da Silva, A G, additional, Hallan, B, additional, Da Silva, M J, additional, Velozo, G S, additional, Santos, C F, additional, Sousa, J C, additional, Távora, F R F, additional, Bessa Jr, J, additional, Nascimento, N R F, additional, and Reges, R, additional

Published
2024
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4. On the understanding of pulsations in the atmosphere of roAp stars: phase diversity and false nodes

Author

Sousa, J. C. and Cunha, M

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Studies based on high-resolution spectroscopic data of rapidly oscillating Ap stars show a surprising diversity of pulsation behavior in the atmospheric layers, pointing, in particular, to the co-existence of running and standing waves. The correct interpretation of these data requires a careful modelling of pulsations in these magnetic stars. In light of this, in this work we present a theoretical analysis of pulsations in roAp stars, taking into account the direct influence of the magnetic field. We derive approximate analytical solutions for the displacement components parallel and perpendicular to the direction of the magnetic field, that are appropriate to the outermost layer. From these, we determine the expression for the theoretical radial velocity for an observer at a general position, and compute the corresponding pulsation amplitude and phase as function of height in the atmosphere. We show that the integral for the radial velocity has contributions from three different types of wave solutions, namely, running waves, evanescent waves, and standing waves of nearly constant amplitude. We then consider a number of case studies to illustrate the origin of the different pulsational behaviour that is found in the observations. Concerning pulsation amplitude, we find that it generally increases with atmospheric height. Pulsation phase, however, shows a diversity of behaviours, including phases that are constant, increasing, or decreasing with atmospheric height. Finally, we show that there are situations in which the pulsation amplitude goes through a zero, accompanied by a phase jumps of $\pi$, and argue that such behaviour does not correspond to a pulsation node in the outermost layers of the star, but rather to a visual effect, resulting from the observers inability to resolve the stellar surface., Comment: 21 pages, 25 figures

Published
2011
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5. Direct evidence of enhanced Ga interdiffusion in InAs vertically aligned free-standing nanowires

Author

Gonz'alez, J. C., Malachias, A., de Sousa, J. C., Andrade, R-Ribeiro, Moreira, M. V. B., and de Oliveira, A. G.

Subjects
Condensed Matter - Materials Science
Abstract

We present direct evidence of enhanced Ga interdiffusion in InAs free-standing nanowires grown at moderate temperatures by molecular beam epitaxy on GaAs (111)B. Scanning electron microscopy together with X-ray diffraction measurements in coplanar and grazing incidence geometries show that nominally grown InAs NWs are actually made of In$_{0.86}$Ga$_{0.14}$As. Unlike typical vapor-liquid-solid growth, these nanowires are formed by diffusion-induced growth combined with strong interdiffusion from substrate material. Based on the experimental results, a simple nanowire growth model accounting for the Ga interdiffusion is also presented. This growth model could be generally applicable to the molecular beam heteroepitaxy of III-V nanowires.

Published
2008

6. A PESQUISA E A INICIAÇÃO CIENTÍFICA NO SUL DO MARANHÃO Coleção Dizeres sul-maranhenses Volume 2

Author

PILLATT, Fábio Roberto, primary, Silva, Camila Sousa da, additional, FABRIN, D. H. C., additional, PILLATT, L. R. B., additional, SOUSA, FÁBIO DA SILVA, additional, DANELLI JÚNIOR, C. A., additional, PEREIRA, E. M., additional, UNSER, ROSEMARA, additional, FONTES, TAYNARA FRANCISCA BATISTA, additional, HOOGERHEIDE, CARLINE H, additional, BAZIQUETO, E. P., additional, ALENCAR, MILENA FERREIRA, additional, NASCIMENTO, J. C., additional, MENDONÇA, M. N., additional, POSSANI, P. K., additional, SOUSA, P. N., additional, SANTOS, M. H. A., additional, SOUZA, F. I. L., additional, MIRANDA, L. S., additional, SILVA, E. R. C., additional, SOUSA, JAKSON FERREIRA DE, additional, TURIBUS, S. N., additional, SANTOS, A. C. G. F., additional, PAULA, GABRIELLE REBECCHI DE, additional, BARROS, J. C., additional, GODINHO, J. L. S., additional, MARTINS, A. P. S., additional, MORAIS, H. S., additional, DELLA FLORA, Kátia. T. L., additional, HILLESHEIM, B., additional, DARSIE, Camilo, additional, OLIVEIRA FILHO, A. S. B., additional, SANTOS, D. C., additional, MIRANDA, JHONATAN LOPES DE, additional, SOUSA, J. C., additional, REIS, F. B., additional, SANTOS, J. C., additional, NOGUEIRA, ADRIANE TAVARES DOS SANTOS, additional, SILVA, F. R. R., additional, DO ESPÍRITO SANTO FONSECA, Gabriel, additional, RIBEIRO, Monique F. S., additional, CARVALHO, THALITA MARIA QUEIROZ CAPUCHINHO, additional, NUNES, R. K. L., additional, MATOS, A. P., additional, SOUZA, K. K. O., additional, MARQUES, L.F., additional, and MORAES, L. A. N., additional

Published
2020
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7. Towards the undestanding of radial velocity pulsation in roAp stars

Author

Sousa, J. C. and Cunha, M. S.

Subjects
Astrophysics
Abstract

High-resolution spectroscopic time series of rapidly oscillating Ap stars show evidence for a co-existence of standing and running waves in their atmospheric layers. With the purpose of understanding these observations we have carried out a theoretical analysis of the pulsations in the outermost layers of these stars, starting from the simplest possible model that still retains all important physical ingredients. In our analysis we considered an isothermal atmosphere in a plane-parallel approximation. Moreover we assumed that in the region considered the magnetic pressure is much larger than the gas pressure and, consequently, that the magnetoacoustic wave has decoupled into its acoustic and magnetic components. Using the analytical solutions for the velocity components appropriate to this model we estimate the velocity component parallel to the line of sight averaged over the visible stellar disk. Fitting the latter to a function of the form Acos($\sigma$t+phase), with $\sigma$ the dimensionless oscillation frequency and t the dimensionless time, we derive the amplitude A and the phase for our model as function of height in the atmosphere., Comment: 5 pages and 5 figures

Published
2007
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14. Redes sociais online, exposição digital e cyberbullying: perfis de vulnerabilidade de universitários de Cabo Verde

Author

Sousa, J. C., Lopes, P., and Javier Sierra Sánchez, Almudena Barrientos

Subjects
Redes sociais online, Cabo Verde, Cyberbullying, Vulnerabilidade digital, Juventude
Abstract

Não sendo fenómeno recente, o bullying adquiriu novos contornos com o aparecimento e a multiplicação de media sociais, em particular redes sociais online, sua massificada utilização, popularidade e (não raras vezes) uso acrítico, especialmente pelos mais jovens. Estas plataformas de produção e distribuição de conteúdos alimentam-se da exposição dos seus utilizadores, dos dados que estes lhes oferecem, da pegada digital que aí imprimem - e que as empresas tecnológicas comercializam. É, portanto, lícito assumir que quanto maior a exposição nas redes sociais online, maior a possibilidade de riscos e danos, como o cyberbullying. Nesta comunicação, pretendemos contribuir para colmatar uma lacuna: revelar as práticas, riscos e danos digitais de jovens universitários de Cabo Verde. A partir da aplicação de um inquérito por questionário a mais de duas centenas de universitários procurou se perceber como é feita a gestão das redes sociais online e como esta impacta no contacto com situações de cyberbullying entre os inquiridos e os seus contactos mais próximos. info:eu-repo/semantics/acceptedVersion

Published
2021

16. Correction to: Is diet partly responsible for differences in COVID-19 death rates between and within countries? (Clinical and Translational Allergy, (2020), 10, 1, (16), 10.1186/s13601-020-00323-0)

Author

Bousquet, J., Anto, J. M., Iaccarino, G., Czarlewski, W., Haahtela, T., Anto, A., Akdis, C. A., Blain, H., Canonica, G. W., Cardona, V., Cruz, A. A., Illario, M., Ivancevich, J. C., Jutel, M., Klimek, L., Kuna, P., Laune, D., Larenas-linnemann, D., Mullol, J., Papadopoulos, N. G., Pfaar, O., Samolinski, B., Valiulis, A., Yorgancioglu, A., Zuberbier, T., Latiff, A. H. A., Abdullah, B., Aberer, W., Abusada, N., Adcock, I., Afani, A., Agache, I., Aggelidis, X., Agustin, J., Akdis, C., Akdis, M., Al-Ahmad, M., Bassam, A. A. -Z., Aldrey-Palacios, O., Cuesta, E. A., Alzaabi, A., Amad, S., Ambrocio, G., Annesi-Maesano, I., Ansotegui, I., Anto, J., Arshad, H., Artesani, M. C., Asayag, E., Avolio, F., Azhari, K., Baiardini, I., Bajrovic, N., Bakakos, P., Mongono, S. B., Balotro-Torres, C., Barba, S., Barbara, C., Barbosa, E., Barreto, B., Bartra, J., Bateman, E. D., Battur, L., Bedbrook, A., Barajas, M. B., Beghe, B., Bel, E., Kheder, A. B., Benson, M., Berghea, C., Bergmann, K. -C., Bernstein, D., Bewick, M., Bialek, S., Bialoszewski, A., Bieber, T., Billo, N., Bilo, M. B., Bindslev-Jensen, C., Bjermer, L., Marciniak, M. B., Bond, C., Boner, A., Bonini, M., Bonini, S., Bosnic-Anticevich, S., Bosse, I., Botskariova, S., Bouchard, J., Boulet, L. -P., Bourret, R., Bousquet, P., Braido, F., Briggs, A., Brightling, C., Brozek, J., Buhl, R., Bumbacea, R., Cabanas, M. T. B., Bush, A., Busse, W. W., Buters, J., Caballero-Fonseca, F., Calderon, M. A., Calvo, M., Camargos, P., Camuzat, T., Cano, A., Capriles-Hulett, A., Caraballo, L., Carlsen, K. -H., Caro, J., Carr, W., Carreon-Asun-cion, F., Carriazo, A. M., Casale, T., Castor, M. A., Castro, E., Cecchi, L., Sarabia, A. C., Chandrasekharan, R., Chang, Y. -S., Chato-Andeza, V., Chatzi, L., Chatzidaki, C., Chavannes, N. H., Chen, Y., Cheng, L., Chivato, T., Chkhartishvili, E., Christoff, G., Chrystyn, H., Chu, D. K., Chua, A., Chuchalin, A., Chung, K. F., Ciceran, A., Cingi, C., Ciprandi, G., Cirule, I., Coelho, A. C., Constantinidis, J., Sousa, J. C., Costa, E., Costa, D., Dominguez, M. C. C., Coste, A., Cox, L., Cullen, J., Custovic, A., Cvetkovski, B., D'Amato, G., Silva, J. D., Dahl, R., Dahlen, S. -E., Daniilidis, V., Nahhas, L. D., Darsow, U., Blay, F., Guia, E. D., Santos, C., Keenoy, E. D. M., Vries, G. D., Deleanu, D., Demoly, P., Denburg, J., Devillier, P., Didier, A., Dimou, M., Dinh-Xuan, A. T., Djukanovic, R., Dokic, D., Silva, M. G. D., Douagui, H., Douladiris, N., Doulaptsi, M., Dray, G., Dubakiene, R., Durham, S., Dykewicz, M., Ebo, D., Edelbaher, N., Eklund, P., El-Gamal, Y., El-Sayed, Z. A., El-Sayed, S. S., El-Seify, M., Emuzyte, R., Enecilla, L., Espinoza, H., Farrell, J., Fernandez, L., Wagner, A. F., Fiocchi, A., Fokkens, W. J., Fontaine, J. -F., Forastiere, F., Fuentes, J. M., Gaerlan-resureccion, E., Gaga, M., Romero, J. L. G., Gamkrelidze, A., Garcia, A., Cobas, C. Y. G., Gayraud, J., Gemicioglu, B., Genova, S., Gereda, J., Wijk, R. G., Gomez, M., Diaz, S. G., Gotua, M., Grigoreas, C., Grisle, I., Guidacci, M., Guldemond, N., Gutter, Z., Guzman, A., Halloum, R., Hamelmann, E., Hammadi, S., Harvey, R., Heinrich, J., Hejjaoui, A., Hellquist-Dahl, B., Velazquez, L. H., Hew, M., Hossny, E., Howarth, P., Hrubisko, M., Villalobos, Y. R. H., Humbert, M., Hyland, M., Ibrahim, M., Ilyina, N., Irani, C., Ispayeva, Z., Jares, E., Jarvis, D., Jassem, E., Jenko, K., Uscanga, R. D. J., Johnston, S., Joos, G., Jost, M., Julge, K., Jung, K. -S., Just, J., Kaidashev, I., Kalayci, O., Kalyoncu, F., Kapsali, J., Kardas, P., Karjalainen, J., Kasala, C. A., Katotomichelakis, M., Kazi, B., Keil, T., Keith, P., Khaitov, M., Khaltaev, N., Kim, Y. -Y., Kleine-Tebbe, J., Koffi N'Goran, B., Kompoti, E., Kopac, P., Koppelman, G., Jeverica, A. K., Kosnik, M., Kostov, K. V., Kowalski, M. L., Kralimarkova, T., Vrscaj, K. K., Kraxner, H., Kreft, S., Kritikos, V., Kudlay, D., Kull, I., Kupczyk, M., Kvedariene, V., Kyriakakou, M., Lalek, N., Lane, S., Larenas-Linnemann, D., Latiff, A., Lau, S., Lavrut, J., Le, L., Lessa, M., Levin, M., Li, J., Lieberman, P., Liotta, G., Lipworth, B., Liu, X., Lobo, R., Lodrup Carlsen, K. C., Lombardi, C., Louis, R., Loukidis, S., Lourenco, O., Luna Pech, J. A., Madjar, B., Magnan, A., Mahboub, B., Mair, A., Mais, Y., van der Zee, A. -H. M., Makela, M., Makris, M., Malling, H. -J., Mandajieva, M., Manning, P., Manousakis, M., Maragoudakis, P., Marshall, G., Martins, P., Masjedi, M. R., Maspero, J. F., Campos, J. J. M., Maurer, M., Mavale-Manuel, S., Meco, C., Melen, E., Melo-Gomes, E., Meltzer, E. O., Menditto, E., Menzies-Gow, A., Merk, H., Michel, J. -P., Miculinic, N., Midao, L., Mihaltan, F., Mikael, K., Mikos, N., Milenkovic, B., Mitsias, D., Moalla, B., Moda, G., Martinez, M. D. M., Mohammad, Y., Moin, M., Molimard, M., Momas, I., Monaco, A., Montefort, S., Mora, D., Morais-Almeida, M., Mosges, R., Mostafa, B. E., Munter, L., Muraro, A., Murray, R., Mustakov, T., Naclerio, R., Nadif, R., Nakonechna, A., Namazova-Baranova, L., Navarro-Locsin, G., Neffen, H., Nekam, K., Neou, A., Nicod, L., Niederberger-Leppin, V., Niedoszytko, M., Nieto, A., Novellino, E., Nunes, E., Nyembue, D., O'Hehir, R., Odjakova, C., Ohta, K., Okamoto, Y., Okubo, K., Oliver, B., Onorato, G. L., Orru, M. P., Ouedraogo, S., Ouoba, K., Paggiaro, P. L., Pagkalos, A., Palaniappan, S. P., Pali-Scholl, I., Palkonen, S., Palmer, S., Bunu, C. P., Panzner, P., Papanikolaou, V., Papi, A., Paralchev, B., Paraskevopoulos, G., Park, H. S., Passalacqua, G., Patella, V., Pavord, I., Pawankar, R., Pedersen, S., Peleve, S., Pereira, A., Perez, T., Pham-Thi, N., Pigearias, B., Pin, I., Piskou, K., Pitsios, C., Pitsios, K., Plavec, D., Poethig, D., Pohl, W., Susic, A. P., Popov, T. A., Portejoie, F., Potter, P., Poulsen, L., Prados-Torres, A., Prarros, F., Price, D., Prokopakis, E., Puy, R., Rabe, K., Raciborski, F., Ramos, J., Recto, M. T., Reda, S. M., Regateiro, F., Reider, N., Reitsma, S., Repka-Ramirez, S., Rimmer, J., Yeverino, D. R., Rizzo, J. A., Robalo-Cordeiro, C., Roberts, G., Roche, N., Gonzalez, M. R., Zagal, E. R., Rolland, C., Roller-Wirns-berger, R., Rodriguez, M. R., Romano, A., Rombaux, P., Romualdez, J., Rosado-Pinto, J., Rosario, N., Rosenwasser, L., Rottem, M., Rouadi, P., Rovina, N., Sinur, I. R., Ruiz, M., Segura, L. T. R., Ryan, D., Sagara, H., Sakai, D., Sakurai, D., Saleh, W., Salimaki, J., Salina, H., Samitas, K. -N., Coronel, M. G. S., Sanchez-Borges, M., Sanchez-Lopez, J., Sarafoleanu, C., Serpa, F. S., Sastre-Dominguez, J., Scadding, G., Scheire, S., Schmid-Grendelmeier, P., Schuhl, J. F., Schunemann, H., Schvalbova, M., Scichilone, N., Sepulveda, C., Serrano, E., Sheikh, A., Shields, M., Shishkov, V., Siafakas, N., Simeonov, A., Simons, E. F., Sisul, J. C., Sitkauskiene, B., Skrindo, I., Soklic, T., Sole, D., Sooronbaev, T., Soto-Martinez, M., Sova, M., Spertini, F., Spranger, O., Stamataki, S., Stefanaki, L., Stellato, C., Stelmach, R., Sterk, P., Strandberg, T., Stute, P., Subramaniam, A., Ulrik, C. S., Sutherland, M., Sylvestre, S., Syrigou, A., Barata, L. T., Takovska, N., Tan, R., Tan, F., Tan, V., Tang, I. P., Taniguchi, M., Tannert, L., Tattersall, J., Teixeira, M. D. C., Thijs, C., Thomas, M., To, T., Todo-Bom, A. M., Togias, A., Tomazic, P. -V., Toppila-Salmi, S., Toskala, E., Triggiani, M., Triller, N., Triller, K., Tsiligianni, I., Ulmeanu, R., Urbancic, J., Pereira, M. U., Vachova, M., Valdes, F., Valenta, R., Rostan, M. V., Valero, A., Vallianatou, M., Valovirta, E., Eerd, M. V., Ganse, E. V., Hage, M., Vandenplas, O., Vasankari, T., Vassileva, D., Ventura, M. T., Vera-Munoz, C., Vicheva, D., Vichyanond, P., Vidgren, P., Viegi, G., Vogelmeier, C., Hertzen, L. V., Vontetsianos, T., Vourdas, D., Wagenmann, M., Walker, S., Wallace, D., Wang, D. Y., Waserman, S., Wickman, M., Williams, S., Williams, D., Wilson, N., Woo, K., Wright, J., Wroczynski, P., Xepapadaki, P., Yakovliev, P., Yamaguchi, M., Yan, K., Yap, Y. Y., Yawn, B., Yiallouros, P., Yoshihara, S., Young, I., Yusuf, O. B., Zaidi, A., Zaitoun, F., Zar, H., Zernotti, M., Zhang, L., Zhong, N., and Zidarn, M.

Published
2020

17. Size-dependent bandgap and particle size distribution of colloidal semiconductor nanocrystals.

Author

Ferreira, D. L., Sousa, J. C. L., Maronesi, R. N., Bettini, J., Schiavon, M. A., Teixeira, A. V. N. C., and Silva, A. G.

Subjects
BAND gaps, PARTICLE size distribution, COLLOIDAL semiconductors, NANOCRYSTALS, ATOMIC force microscopy
Abstract

Anewanalytical expression for the size-dependent bandgap of colloidal semiconductor nanocrystals is proposed within the framework of the finite-depth square-well effective mass approximation in order to provide a quantitative description of the quantum confinement effect. This allows one to convert optical spectroscopic data (photoluminescence spectrum and absorbance edge) into accurate estimates for the particle size distributions of colloidal systems even if the traditional effective mass model is expected to fail, which occurs typically for very small particles belonging to the so-called strong confinement limit. By applying the reported theoretical methodologies to CdTe nanocrystals synthesized through wet chemical routes, size distributions are inferred and compared directly to those obtained from atomic force microscopy and transmission electron microscopy. This analysis can be used as a complementary tool for the characterization of nanocrystal samples of many other systems such as the II-VI and III-V semiconductor materials. [ABSTRACT FROM AUTHOR]

Published
2017
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22. Invisibilidade e negatividade: o discurso mediático sobre ambiente em Portugal

Author

Sousa, J. C., João Ferrão, Ana Delicado, Ana Horta, Carla Gomes, David Travassos, Jussara Rowland, Madalena Santos, and Simone Tulumello

Abstract

Uma tentativa de resposta, ainda que parcial, ao facto de Portugal ser, no contexto europeu, um dos países que apresenta valores mais elevados no que concerne à visão das alterações climáticas como consequência de fatores humanos, de acordo com o ESS8, consiste em perspetivar a menor confiança dos portugueses relativamente à informação proveniente e que circula nas redes sociais digitais como o Facebook e/ou Twitter, onde, aliás, o impacto das chamadas Fake News e a contrainformação intensifica-se pela própria natureza da arquitetura destas plataformas online. Desta forma, assumimos que a excessiva exposição a informação é, a determinada altura, o terreno fértil para a desinformação. Destas considerações resulta uma potencial agenda de investigação que está longe de se constituir e ainda mais distante de se concretizar, para desse modo se compreender melhor os fenómenos ambientais e o modo como são construídas as representações mediáticas sobre os mesmos e, desta forma, disponibilizar mais e melhor conhecimento à comunidade e a quem influenciar políticas públicas de prevenção, adaptação e/ou mitigação às alterações climáticas e aos riscos a elas associados. info:eu-repo/semantics/publishedVersion

Published
2019

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