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11,632 results on '"SILVA F"'

1. Descemet’s Membrane Detachment: An Intraoperative Complication in Cataract Surgery with Phacoemulsification

Author

Gonzalez AL, Silva F, Barrientos R, and Paredes F

Subjects
descemet membrane detachment, anterior segment coherence tomography, ultrabomicroscopy., Medicine (General), R5-920
Abstract

Ana Luisa González, Fermín Silva, Robinson Barrientos, Fabricio Paredes Department of Ophthalmology, Research Department Clínica La Luz, 1148 Lima, PeruCorrespondence: Ana Luisa GonzálezDepartment of Ophthalmology, Research Department Clínica La Luz, Av. Arequipa, 1148 Lima, PeruTel +51947273992Email Dra.analuisagonzalez88@gmail.comAbstract: Descemet’s membrane detachment (DMD) is a complication fundamentally associated with cataract surgery, the subclinical presentation being higher than expected. There are many varied treatments, from simple observation to penetrating keratoplasty. We present a case report of a 78-year-old male patient, without comorbidities, who underwent cataract surgery with phacoemulsification plus intraocular lens implantation in the capsular bag of the left eye. During the intraoperative procedure, he presented a DMD (height of 350 um and length of 3 mm in Zone 1 according to the HELP algorithm), managed with adaptive viscoelastic under the soft-shell technique in the same operative act, injection of iso-expansile SF6 (20%) intracameral plus postural positioning for 2 hours carried out 48 hours after surgery plus intensive topical treatment with hypertonic sodium chloride and steroidal anti-inflammatory drugs. At 72 hours after the operation of the application of the gas bubble, he presented with a transparent cornea and a best-corrected visual acuity of 20/80, which finally for his ophthalmological control at 8 weeks presented definitive resolution of the case in the AS-OCT and with a BCVA of 20/30.Keywords: descemet membrane detachment, anterior segment coherence tomography, ultrabiomicroscopy

Published
2020

2. Management of Secondary Keratouveitis in a Wasp Sting Patient in a Jungle Region of Peru

Author

González AL, Silva F, and Barrientos R

Subjects
hymenoptera, cornea, bee, wasp, sting, anterior chamber, acute keratouveitis., Medicine (General), R5-920
Abstract

Ana Luisa González, Fermin Silva, Robinson Barrientos Department of Ophthalmology, Research Department Clinica La Luz, Lima, PeruCorrespondence: Ana Luisa GonzálezDepartment of Ophthalmology, Research Department Clinica La Luz, Av. Arequipa 1148, Lima, PeruTel +51 947273992Email Dra.analuisagonzalez88@gmail.comAbstract: Wasp stings are considered an ophthalmological emergency as they can be complicated when they occur near the eyelids or especially on the cornea. Due to type I hypersensitivity response, such as epithelial defect, corneal edema, loss of endothelial cells, anterior uveitis, optic neuritis and, therefore, permanent loss of vision due to anterior segment ischemia. It warns that the wasp stinger has a saw-shaped texture, contains toxins that inflame the area where it stings. Due to the immunological and toxic effects of the stinger and its venom infiltrates the cornea. We present the case of a 32-year-old man who presented keratouveitis secondary to a wasp sting in a region of the jungle of Peru. He was treated emergency with intensive steroid therapy to reduce the toxic effects. His follow-up up to 2 months was successful, leaving only a 1 mm central leukoma where the bite occurred, which did not impair his vision.Keywords: hymenoptera, cornea, bee, wasp, sting, anterior chamber, acute keratouveitis

Published
2020

3. Phenobot - Intelligent photonics for molecular phenotyping in Precision Viticulture

Author

Martins R.C., Cunha M., Santos F., Tosin R., Barroso T.G., Silva F., Queirós C., Pereira M.R., Moura P., Pinho T., Boaventura J., Magalhães S., Aguiar A.S., Silvestre J., Damásio M., Amador R., Barbosa C., Martins C., Araújo J., Vidal J.P., Rodrigues F., Maia M., Rodrigues V., Garcia A., Raimundo D., Trindade M., Pestana C., and Maia P.

Subjects
Microbiology, QR1-502, Physiology, QP1-981, Zoology, QL1-991
Abstract

The Phenobot platform is comprised by an autonomous robot, instrumentation, artificial intelligence, and digital twin diagnosis at the molecular level, marking the transition from pure data-driven to knowledge-driven agriculture 4.0, towards a physiology-based approach to precision viticulture. Such is achieved by measuring the plant metabolome ‘in vivo' and 'in situ', using spectroscopy and artificial intelligence for quantifying metabolites, e.g.: i. grapes: chlorophylls a and b, pheophytins a and b, anthocyanins, carotenoids, malic and tartaric acids, glucose and fructose; ii. foliage: chlorophylls a and b, pheophytins a and b, anthocyanins, carotenoids, nitrogen, phosphorous, potassium, sugars, and leaf water potential; and iii. soil nutrients (NPK). The geo-referenced metabolic information of each plant (organs and tissues) is the basis of multi-scaled analysis: i. geo-referenced metabolic maps of vineyards at the macroscopic field level, and ii. genome-scale 'in-silico' digital twin model for inferential physiology (phenotype state) and omics diagnosis at the molecular and cellular levels (transcription, enzyme efficiency, and metabolic fluxes). Genome-scale 'in-silico' Vitis vinifera numerical network relationships and fluxes comprise the scientific knowledge about the plant's physiological response to external stimuli, being the comparable mechanisms between laboratory and field experimentation - providing a causal and interpretable relationship to a complex system subjected to external spurious interactions (e.g., soil, climate, and ecosystem) scrambling pure data-driven approaches. This new approach identifies the molecular and cellular targets for managing plant physiology under different stress conditions, enabling new sustainable agricultural practices and bridging agriculture with plant biotechnology, towards faster innovations (e.g. biostimulants, anti-microbial compounds/mechanisms, nutrition, and water management). Phenobot is a project under the Portuguese emblematic initiative in Agriculture 4.0, part of the Recovery and Resilience Plan (Ref. PRR: 190 Ref. 09/C05-i03/2021 – PRR-C05-i03-I-000134).

Published
2023
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4. On the implementation of a primal-dual algorithm for second order time-dependent Mean Field Games with local couplings

Author

Briceño-Arias L., Kalise D., Kobeissi Z., Laurière M., Mateos González Á., and Silva F. J.

Subjects
Applied mathematics. Quantitative methods, T57-57.97, Mathematics, QA1-939
Abstract

We study a numerical approximation of a time-dependent Mean Field Game (MFG) system with local couplings. The discretization we consider stems from a variational approach described in [14] for the stationary problem and leads to the finite difference scheme introduced by Achdou and Capuzzo-Dolcetta in [3]. In order to solve the finite dimensional variational problems, in [14] the authors implement the primal-dual algorithm introduced by Chambolle and Pock in [20], whose core consists in iteratively solving linear systems and applying a proximity operator. We apply that method to time-dependent MFG and, for large viscosity parameters, we improve the linear system solution by replacing the direct approach used in [14] by suitable preconditioned iterative algorithms.

Published
2019
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9. Measurement of the background in the CMS muon detector in pps=13TeV-collisions at pps=13TeV pps=13TeV

Author

Tytgat, M., Muhammad, A., De Lentdecker, G., Jaramillo, J., Moureaux, L., Pétré, L., Yang, Y., Rendón, C., Gokbulut, G., Hong, Y., Samalan, A., Alves, G. A., Marujo da Silva, F., Alves Coelho, E., Barroso Ferreira Filho, M., Da Costa, E. M., De Jesus Damiao, D., Ferreira, B. C., Fonseca De Souza, S., Mota Amarilo, K., Nogima, H., Santoro, A., Thiel, M., Aleksandrov, A., Dimitrov, L., Hadjiiska, R., Iaydjiev, P., Misheva, M., Mitev, G., Ratchev, L., Rashevski, G., Shopova, M., Sultanov, G., Dimitrov, A., Litov, L., Pavlov, B., Petkov, P., Petrov, A., Shumka, E., Keshri, S., Thakur, S., Chen, M., Dong, X., Gong, W., Hou, Q., Jiang, C., Kou, H., Liu, Z.-A., Luo, W., Song, J., Sun, L., Wang, N., Wang, Y., Wang, Z., Zhang, C., Zhang, Y., Zhang, H., Zhao, J., Agapitos, A., Ban, Y., Levin, A., Li, Q., Qian, S. J., Wang, D., Wang, K., You, Z., Avila, C., Barbosa Trujillo, D. A., Cabrera, A., Florez, C. A., Fraga, J., Reyes Vega, J. A., Ramirez, F., Rodriguez, M., Ruiz, J. D., Vanegas, N., Abdalla, H., Abdelalim, A. A., Assran, Y., Radi, A., Crotty, I., Mahmoud, M. A., Balleyguier, L., Chen, X., Combaret, C., Galbit, G., Gouzevitch, M., Grenier, G., Laktineh, I. B., Luciol, A., Mirabito, L., Tromeur, W., Bagaturia, I., Lomidze, I., Kemularia, O., Tsamalaidze, Z., Böttger, U., Eliseev, D., Hebbeker, T., Hoepfner, K., Merschmeyer, M., Ivone, F., Mukherjee, S., Nowotny, F., Philipps, B., Reithler, H., Sharma, A., Torres Da Silva De Araujo, F., Wiedenbeck, S., Zaleski, S., Zantis, F. P., Abbas, M., Mallows, S., Bencze, G., Beni, N., Molnar, J., Szillasi, Z., Teyssier, D., Ujvari, B., Zilizi, G., Babbar, J., Bansal, S., Bhatnagar, V., Chauhan, S., Kaur, A., Kaur, H., Kaur Sahota, A., Kumar, S., Sheokand, T., Singh, J., Choudhary, B. C., Kumar, A., Kumar Saini, M., Naimuddin, M., Majumdar, N., Mukhopadhyay, S., Rout, P., Amoozegar, V., Boghrati, B., Ebraimi, M., Mohammadi Najafabadi, M., Zareian, E., Abbrescia, M., Aly, R., Buonsante, M., Colaleo, A., De Filippis, N., Dell’Olio, D., De Robertis, G., Elmetenawee, W., Ferrara, N., Franco, M., Iaselli, G., Lacalamita, N., Licciulli, F., Loddo, F., Maggi, M., Martiradonna, S., Nuzzo, S., Longo, L., Pellecchia, A., Pugliese, G., Radogna, R., Ramos, D., Ranieri, A., Simone, F. M., Stamerra, A., Troiano, D., Venditti, R., Verwilligen, P., Zaza, A., Abbiendi, G., Baldanza, C., Battilana, C., Benvenuti, A., Borgonovi, L., Cafaro, V., Cavallo, F. R., Crupano, A., Cuffiani, M., Dallavalle, G. M., Fabbri, F., Fanfani, A., Fasanella, D., Giacomelli, P., Giordano, V., Guandalini, C., Guiducci, L., Lo Meo, S., Lunerti, L., Marcellini, S., Masetti, G., Navarria, F. L., Paggi, G., Perrotta, A., Primavera, F., Rossi, A. M., Rovelli, T., Torromeo, G., Benussi, L., Bianco, S., Campagnola, R., Caponero, M., Colafranceschi, S., Meola, S., Passamonti, L., Piccolo, D., Pierluigi, D., Raffone, G., Russo, A., Saviano, G., Buontempo, S., Cagnotta, A., Carnevali, F., Cassese, F., Cavallo, N., De Iorio, A., Fabozzi, F., Iorio, A. O. M., Lista, L., Paolucci, P., Passeggio, G., Rossi, B., Barcellan, L., Bellato, M., Benettoni, M., Bergnoli, A., Bragagnolo, A., Carlin, R., Castellani, L., Checchia, P., Ciano, L., Colombo, A., Corti, D., Gasparini, F., Gasparini, U., Gonella, F., Gozzelino, A., Griggio, A., Grosso, G., Gulmini, M., Isocrate, R., Lusiani, E., Maron, G., Margoni, M., Meneguzzo, A. T., Migliorini, M., Modenese, L., Montecassiano, F., Negrello, M., Passaseo, M., Pazzini, J., Ramina, L., Rampazzo, M., Rebeschini, M., Ronchese, P., Rossin, R., Simonetto, F., Toffano, M., Toniolo, N., Triossi, A., Ventura, S., Zanetti, M., Zatti, P. G., Zotto, P., Zucchetta, A., AbuZeid, S., Aimè, C., Braghieri, A., Calzaferri, S., Fiorina, D., Gigli, S., Montagna, P., Riccardi, C., Salvini, P., Vai, I., Vitulo, P., Amapane, N., Cotto, G., Dattola, D., De Remigis, P., Kiani, B., Mariotti, C., Maselli, S., Pelliccioni , M., Rotondo, F., Staiano, A., Trocino, D., Umoret, G., Asilar, E., Kim, T. J., Merlin, J. A., Choi, S., Hong, B., Lee, K. S., Goh, J., Choi, J., Kim, J., Yang, U., Yoon, I., Jang, W., Heo, J., Kang, D., Kang, Y., Kim, D., Kim, S., Ko, B., Lee, J. S. H., Park, I. C., Watson, I. J., Yang, S., Jeong, Y., Lee, Y., Yu, I., Alasfour, G., Beyrouthy, T., Gharbia, Y., Maghrbi, Y., Otkur, M., Castilla-Valdez, H., Crotte Ledesma, H., Lopez-Fernandez, R., Sánchez Hernández, A., Ramírez García, M., Vazquez, E., Shah, M. A., Zaganidis, N., Pedraza, I., Uribe Estrada, C., Ahmad, A., Ahmed, W., Asghar, M. I., Hoorani, H. R., Muhammad, S., Wajid, A., Alcaraz Maestre, J., Álvarez Fernández, A., Fernandez Bedoya, Cristina F., Blanco Ramos, L. C., Calvo, E., Carrillo Montoya, C. A., Cela Ruiz, J. M., Cepeda, M., Cerrada, M., Colino, N., Cuadrado Calzada, S., Cuchillo Ortega, J., De La Cruz, B., de Lara Rodríguez, C. I., Fernández Del Val, D., Fernández Ramos, J. P., Fouz, M. C., Francia Ferrero, D., García Romero, J., Gonzalez Lopez, O., Goy Lopez, S., Josa, M. I., León Holgado, J., Manzanilla Carretero, O., Martín Martín, I., Martínez Morales, J. J., Martín Viscasillas, E., Moran, D., Navarro Tobar, Á., Paz Herrera, R., Puras Sánchez, J. C., Puerta Pelayo, J., Pulido Ferrero, S., Redondo, I., Redondo Ferrero, D. D., Salto Parra, V., Sánchez Navas, S., Sastre, J., Urda Gómez, L., Vazquez Escobar, J., de Trocóniz, J. F., Frias Garcia-Lago, F., Reyes-Almanza, R., Alvarez Gonzalez, B., Cuevas, J., Fernandez Menendez, J., Folgueras, S., Gonzalez Caballero, I., Leguina López, P., Palencia Cortezon, E., Ramón Álvarez, C., Prado Pico, J., Rodríguez Bouza, V., Soto Rodríguez, A., Trapote, A., Villalba, C. Vico, Kailasapathy, B., Malagalage, K., Sonnadara, D. U. J., Wickramarathna, D. D. C., Dharmaratna, W. G. D., Liyanage, K., Perera, N., Wickramage, N., Aspell, P., Bianco, M., Bozzato, D., Brachet, S., Conde Garcia, A., Dabrowski, A., De Oliveira, R., Fallavollita, F., Kicsiny, P., Sharma, A., Hazen, E., May, S., Peck, A., Salyer, K., Suarez, I., Abbott, S., Bonilla, J., Breedon, R., Cai, H., Cox, P. T., Erbacher, R., Kukral, O., McLean, C., Mocellin, G., Mulhearn, M., Regnery, B., Tripathi, M., Waegel, G., Yao, Y., Carlson, J., Cousins, R., Dasgupta, A., Datta, A., Hauser, J., Ignatenko, M., Iqbal, M. A., Lo, C., Saltzberg, D., Schnaible, C., Valuev, V., Clare, R., Gordon, M., Hanson, G., Amin, N., Bradmiller-Feld, J., Campagnari, C., Danielson, T., Dishaw, A., Dorsett, A., Kim, J., Marsh, B., Mei, H., Oshiro, M., Richman, J., Setti, F., Sevilla, M. F., Siddireddy, P., Wang, S., Aruta, C., Barashko, V., Cherepanov, V., Dittrich, M., Korytov, A., Kuznetsova, E., Madorsky, A., Mitselmakher, G., Muthirakalayil Madhu, A., Rawal, N., Terentyev, N., Wang, J., Alsufyani, B., Butalla, S., Elkafrawy, T., Hohlmann, M., Yanes, E., Eysermans, J., Barberis, E., Haddad, Y., Han, Y., Madigan, G., Morse, D. M., Nguyen, V., Wood, D., Bhattacharya, S., Bueghly, J., Chen, Z., Hahn, K. A., Liu, Y., Miao, Y., Monk, D. G., Schmitt, M. H., Taliercio, A., Velasco, M., Bylsma, B., Carrigan, M., De Los Santos, R., Durkin, L. S., Hill, C., Banicz, K., Liu, J., Matveev, M., Padley, B. P., Aebi, D., Ahmad, M., Akhter, T., Bolshov, A., Bouhali, O., Eusebi, R., Gilmore, J., Huang, T., Juska, E., Kamon, T., Kim, H., Kizlov, M., Malhotra, S., Mueller, R., Rabadan, R., Rathjens, D., Safonov, A., Karchin, P. E., Aravind, A., Black, K., De Bruyn, I., Everaerts, P., Galloni, C., Herndon, M., Lanaro, A., Loveless, R., Madhusudanan Sreekala, J., Mondal, S., Teague, D., Vetens, W., Warden, A., Azhgirey, I., Borshch, V., Chtchipunov, L., Egorov, A., Gavrilov, G., Golovtcov, V., Ivanov, M., Ivantchenko, V., Ivanov, Y., Karjavine, V., Khodinov, A., Kim, V., Kurochkin, I. A., Levchenko, P., Murzin, V., Nasybulin, S., Oreshkin, V., Palichik, V., Perelygin, V., Riabchikova, A., Sosnov, D., Sulimov, V., Uvarov, L., Vavilov, S., and Vorobyev, A.

Published
2024
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10. Hybrid Stars Built with Density Dependent Models

Author

Issifu, A., da Silva, F. M., and Menezes, D. P.

Subjects
Nuclear Theory
Abstract

Using a density dependent quark model and a relativistic model within the mean-field approximation for hadrons with density dependent meson-baryon couplings, we construct, for the first time, models that describe hybrid neutron stars consisting of nucleons and exotic baryons (hyperons and $\Delta$-resonances). We do the study using a Maxwell construction. The quark-hadron phase transition in the stellar matter is determined through; the structure, composition, and properties of the hybrid neutron star matter. The macroscopic properties of the star are determined, and the results for these particular models are found to be compatible with recent observational astrophysical data., Comment: 9 pages, 7 figures

Published
2023
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13. A Study on the Epidemiology and Aetiology of Acute Gastroenteritis in Adult Patients Presenting at the Infectious Diseases Hospital in Tirana, Albania

Author

Gentian P. Stroni, Majlinda M. Dhimolea, Silva F. Bino, Pëllumb S. Pipero, Dhimiter V. Kraja, and Suela Y. Sallavaci

Subjects
Aetiology, diarrhoea, enteropathogens, epidemiology, Medicine
Abstract

Background: Acute gastroenteritis remains a common cause of hospital emergency room visits in Albania. However, the aetiology of severe gastroenteritis leading to hospitalization in adults frequently remains unclear. Aims: Our objective was to study the epidemiology and causes of community-acquired, acute gastroenteritis in adult patients presenting to hospital. Study Design: Cross sectional study. Methods: A prospective study was conducted from January 2010 to January 2012, among patients ≥15 years old with community-acquired gastroenteritis presenting to the emergency room of the University Hospital “Mother Theresa” in Tirana, Albania. Stool samples and rectal swabs were collected from the patients for microbiological testing. Results: The median age of the study patients was 33 (15-88) years and 577 (58%) were females. The median age of males was 35 (15-87) years. The vast majority of cases occurred in urban area (849, 85%), p

Published
2014
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14. Kiselev black holes in $f(R,T)$ gravity

Author

Santos, L. C. N., da Silva, F. M., Mota, C. E., Lobo, I. P., and Bezerra, V. B.

Subjects
General Relativity and Quantum Cosmology, High Energy Physics - Theory
Abstract

We obtain new exact solutions for the gravitational field equations in the context of $f(R,T)$ gravity, thereby obtaining different classes of black holes surrounded by fluids, taking into account some specific values of the parameter of the equations of state, $w$. In order to obtain these solutions in the context of $f(R,T)$ gravity, we consider viable particular choices of the $f(R,T)$. Considering an anisotropic energy-momentum tensor, we write the field equations with the required symmetries for this type of solution. Then, we analyze the conditions of energy in a general way and also for particular values of the parameter $w$ of the equation of state. In addition, thermodynamic quantities, such as Hawking temperature and mass associated to the horizons of solutions, are taken into account in our analysis.

Published
2023

17. Valorisation of Leather Wastes from the Footwear Industry via Pyrolysis: Product Yields and Characterisation

Author

Silva, F., Direito, D., Pilão, R., Ribeiro, A. M., Bezaeva, Natalia S., Series Editor, Gomes Coe, Heloisa Helena, Series Editor, Nawaz, Muhammad Farrakh, Series Editor, Galvão, João Rafael da Costa Sanches, editor, Brito, Paulo, editor, Neves, Filipe dos Santos, editor, Almeida, Henrique de Amorim, editor, Mourato, Sandra de Jesus Martins, editor, and Nobre, Catarina, editor

Published
2024
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18. Application for Mobile Devices to Measure Daily Protein Intake in the Elderly: PROT + First Results

Author

Silva, F. C. D., Martins, A. P. S., F.C.D.Silva, F. C. D., Simonato, L. E., Magalhães, D. S. F., Magjarević, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Marques, Jefferson Luiz Brum, editor, Rodrigues, Cesar Ramos, editor, Suzuki, Daniela Ota Hisayasu, editor, Marino Neto, José, editor, and García Ojeda, Renato, editor

Published
2024
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19. Cytotoxic Evaluation of Aqueous Extracts Obtained from Two Brazilian Native Plant Species with Medicinal Potential, Casearia Sylvestris and Hyptis Lacustris

Author

Ambrosio, F. N., da Silva, F. D., Lombello, R. A., Lombello, C. B., Magjarević, Ratko, Series Editor, Ładyżyński, Piotr, Associate Editor, Ibrahim, Fatimah, Associate Editor, Lackovic, Igor, Associate Editor, Rock, Emilio Sacristan, Associate Editor, Marques, Jefferson Luiz Brum, editor, Rodrigues, Cesar Ramos, editor, Suzuki, Daniela Ota Hisayasu, editor, Marino Neto, José, editor, and García Ojeda, Renato, editor

Published
2024
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20. Sewage Sludge: Some Applications in Civil Engineering

Author

Feitosa, M. C. A., Ferreira, S. R. M., Delgado, J. M. P. Q., Silva, F. A. N., Oliveira, J. T. R., Oliveira, P. E. S., Azevedo, A. C., de Freitas, Vasco Peixoto, Series Editor, Costa, Aníbal, Series Editor, and Delgado, João M. P. Q., Series Editor

Published
2024
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22. Non-inertial effects on a non-relativistic quantum harmonic oscillator in the presence of a screw dislocation

Author

Santos, L. C. N., da Silva, F. M., Mota, C. E., and Bezerra, V. B.

Subjects
Quantum Physics, High Energy Physics - Theory
Abstract

We investigate non-inertial effects induced by a rotating frame on a non-relativistic quantum harmonic oscillator as well as of the topology associated to a screw dislocation, which corresponds to a distortion of a vertical line into a vertical spiral. To do this, we obtain the analytical solutions of the time-independent Schr\"odinger equation for this harmonic oscillator potential in this background. The expressions for the energy spectrum are obtained and the solutions for four quantum states, namely $n=0,1,2$ and $3$, are analysed. Our results show that the presence of the topological defect (screw dislocation) as well the fact that we are analysing the system from the point of view of a rotating frame, changes the solutions of Schr\"odinger equation and the corresponding spectrum. Now these quantities depend on the angular velocity of the rotating frame, $\Omega$, and also on the parameter $\beta$, which codifies the presence of the screw dislocation. Particularly, with respect to the energy spectrum of the system the changing is such that when $\Omega$ increases, the energy can increase or decrease depending on the values we assign to the eigenvalues of the angular and linear momenta. Additionally, we observe that the values of the parameter $\beta$ that characterizes the screw dislocation causes a shift in the energy spectrum.

Published
2022
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27. Rapidly rotating neutron stars in $f(R,T)$ gravity

Author

da Silva, F. M., Santos, L. C. N., Mota, C. E., da Costa, T. O. F., and Fabris, J. C.

Subjects
General Relativity and Quantum Cosmology, Astrophysics - High Energy Astrophysical Phenomena
Abstract

In this work, we study the influence of $f(R,T)$ gravity on rapidly rotating neutron stars. First we discuss the main aspects of this modified theory of gravity where the gravitational Lagrangian is an arbitrary function of the Ricci scalar $R$ and of the trace of the energy-momentum tensor $T$. Then we present the basic equations for neutron stars including the equations of state used in the present work to describe the hadronic matter. Some physical quantities of interest are calculated such as mass-radius relations, moments of inertia, angular momentum, and compactness. By considering four different rotation regimes, we obtain results that indicate substantial modifications in the physical properties of neutron stars in $f(R,T)$ gravity when compared to those in the context of general relativity. In particular, the mass-radius relation for sequences of stars indicates that $f(R,T)$ gravity increases the mass and the equatorial radius of the neutron stars for stars rotating with an angular velocity smaller than Kepler limit.

Published
2022
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29. Population dynamics of Euglossinae bees (Hymenoptera, Apidae) in an early second-growth forest of Cajual Island, in the State of Maranhão, Brazil

Author

SILVA F. S. and REBÊLO J. M. M.

Subjects
Euglossinae, Cajual Island, scent baits, Maranhão, Science, Biology (General), QH301-705.5, Zoology, QL1-991, Botany, QK1-989
Abstract

A study was conducted in an early second-growth forest aiming at knowing the richness, relative abundance, seasonal distribution, and hourly frequency of euglossine bees, and their association with scent baits. Male bees were attracted to cineole, vanillin, methyl salicylate, and eugenol. The baits were hooked 1.5 m high and 6 m from one another. The specimens were collected from December 1997 to November 1998, once a month, from 7:00 to 17:00 h. A total of 339 male euglossine bees were caughts, accounting for 19 species and four genera. The most common species was E. cordata, making up 69.9% of the individuals, followed by E. truncata (2.3%), E. violaceifrons, and E. smaragdina (2.1%). The most attractive scent was cineole, which baited 87% of the specimens and 73.7% of the species. Vanillin, the second most visited bait, eured 7.6% of the specimens and 26.3% of the species. E. surinamensis was only collected with this bait. Methyl salicylate and eugenol baited combined 2.6% of the specimens. However, by species numbers Methyl salicylate attracted 21% whereas eugenol was attractive for 15.8% of them. In general, the species were more abundantly found in the rainy season (January-June). The hourly activity data showed that the euglossine bees were attracted to the baits all day long, but at a higher frequency in the morning period, peaking between 8:00 and 10:00 h.

Published
2002

30. Comportamento reológico de dispersões de argilas bentoníticas: efeitos do tipo de ferramenta, velocidade e tempo de agitação

Author

Amorim L. V., Gomes C. M., Silva F. L. H., and Ferreira H. C.

Subjects
planejamento experimental, bentonita, propriedades reológicas, fluidos de perfuração, Engineering (General). Civil engineering (General), TA1-2040
Abstract

Este trabalho teve como objetivo estudar a influência do tipo de ferramenta, da velocidade e do tempo de agitação nas propriedades reológicas de dispersões de quatro amostras de argilas bentoníticas sódicas industrializadas no Estado da Paraíba, Brasil. Foi realizado um planejamento fatorial do tipo 2³ para avaliar os fatores de entrada (tipo de ferramenta, velocidade e tempo de agitação) sobre as viscosidades aparente e plástica e o volume de filtrado. As dispersões foram preparadas na concentração de 4,86% em massa de argila (24,3 g de argila em 500 mL de água deionizada) utilizando ferramentas do tipo palheta corrugada e em forma de borboleta, duas velocidades (10.000 rpm e 17.000 rpm) e dois tempos de agitação (10 e 20 min). As viscosidades aparente e plástica foram determinadas em viscosímetro Fann 35A, e o volume de filtrado, em filtro prensa Fann. Através da regressão dos dados experimentais, verificou-se que as variáveis de entrada não apresentam influências estatisticamente significativas nas propriedades reológicas das dispersões estudadas, bem como, que dentre as quatro argilas estudadas apenas uma apresenta comportamento reológico de acordo com as normas vigentes para uso como agente tixotrópico para fluidos de perfuração à base de água doce.

Published
2002

45. An in vitro System for Studying Pteridine Biosynthesis In Drosophila melanogaster

Author

Escriche B. and Silva F. J.

Subjects
Crystallography, QD901-999
Abstract

In vitro organ culture is a system especially useful for the study of metabolic pathways and their regulation. This report applies such a system to the study of the biosynthesis of pteridines in Drosophila melanogaster, determining in vitro optimal conditions for head cultures, in relation to this metabolic pathway. The validity of the system was tested by applying it to the study of a well-known enzyme, xanthine dehydrogenase, which catalyzes the transformation of pterin into isoxanthopterin. Supplementation experiments with pterin were carried out, determining that, as expected, only those strains having xanthine dehydrogenase activity were able to transform this compound into isoxanthopterin. These results confirm the usefulness of this system for future studies on pteridine metabolism.

Published
1991
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