237 results on '"J. Comas"'
Search Results
2. A new species of Laemostenus Bonelli, 1810 (Coleoptera, Carabidae) from Els Ports Natural Park (Catalonia, northeastern Iberian peninsula)
- Author
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M. Prieto, J. Mederos, and J. Comas
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Zoology ,QL1-991 - Abstract
Un nuevo Laemostenus Bonelli, 1810 (Coleoptera, Carabidae) del Parc Natural dels Ports (Cataluña, nordeste de la península ibérica) Se describe Laemostenus (Antisphodrus) portsensis sp. n., localizada en cinco cavidades del Parc Natural dels Ports. Se compara con sus vecinos geográficos, L. (A.) levantinus (Bolívar, 1919) y L. (A.) lassallei Mateu, 1989, de los que se distingue por la forma de la cabeza y el pronoto, y especialmente por la morfología de la genitalia masculina. Se completa el estudio aportando datos sobre el hábitat y la ecología de la nueva especie.
- Published
- 2015
3. Ammonoids of the Oxynotum Zone and Raricostatum Zone (Densinodulum Subzone) of Sinemurian, Lower Jurassic, in the Asturian and Lusitanian basins
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Íñigo Vitón, María J. Comas-Rengifo, Luís V. Duarte, and Antonio Goy
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General Agricultural and Biological Sciences - Abstract
This research is focused on the ammonoids of Oxynotum Zone and Raricostatum Zone (Densinodulum Subzone) from Asturian (Spain) and Lusitanian (Portugal) basins. They come from expanded sections from where 216 specimens have been collected. These have been classified in eight genera and 15 species that belong to families Echioceratidae, Oxynoticeratidae and Eoderoceratidae. Most of the ammonoids are typical of the Northwest European Province. Echioceratidae is the most frequent in the Asturian Basin, whereas Oxynoticeratidae is the predominant in the Lusitanian Basin. Eoderoceratidae specimens are scarcer, and they are registered only between the middle part of Oxynotum Subzone and the lower part of Densinodulum Subzone. A new species is proposed for the upper part of Oxynotum Subzone of the Lusitanian Basin, Plesechioceras rochai sp. nov., which is relatively frequent. As well, also in Portugal, Cheltonia sp. is registered in Densinodulum Subzone, which is a form different from Cheltonia accipitris. This provides new evidence to support the hypothesis of the relation micro-macroconch between the genera Oxynoticeras (M) and Cheltonia (m). Remarkable differences in the studied area are the presence of Paroxynoticeras salisburgense and Plesechioceras cf. delicatum in the Asturias Basin, and Crucilobiceras densinodulum, associated to Oxynoticeras lymense, in the Lusitanian Basin. https://zoobank.org/NomenclaturalActs/FEF11B83-03CA-4BD6-BB15-F3E9926B7C4F
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- 2023
- Full Text
- View/download PDF
4. síndrome de 'Dumping'
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Juan Carlos del Campo, Enrique J. Comas, and Eduardo Outeda
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RD1-811 ,Surgery ,trastornos digestivos ,gastrectomías - Abstract
Presentado en sesión de 10 de mayo de 1950
- Published
- 2020
5. POS-381 DEEP LEARNING-BASED PREDICTION FOR MORTALITY IN PATIENTS WITH CHRONIC KIDNEY DISEASE: A NEW MODEL DEVELOPED WITH DATA FROM 10.000 PATIENTS OVER THE LAST 11 YEARS
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O. Gallés, N. MONILL-RAYA, A. Morell, J. Serrano, D. Rexach, J. López-Vicario, J. Comas, E. Martinez, and J. Ibeas
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Nephrology - Published
- 2022
6. An automated methodology for mode II delamination tests under fatigue loading based on the real time monitoring of the specimen’s compliance
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J.A. Mayugo, S. Budhe, Josep Costa, A. Rodríguez-Bellido, J. Vicens, J. Comas, Jordi Renart, and Ministerio de Economía y Competitividad (Espanya)
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Composite materials -- Fatigue ,Materials science ,Assaigs de materials ,02 engineering and technology ,Fixture ,Industrial and Manufacturing Engineering ,Composite materials -- Delamination ,0203 mechanical engineering ,Calibration ,Initial value problem ,General Materials Science ,Point (geometry) ,Composite material ,business.industry ,Mechanical Engineering ,Continuous monitoring ,Delamination ,Work (physics) ,Mode (statistics) ,Materials -- Testing ,Structural engineering ,021001 nanoscience & nanotechnology ,020303 mechanical engineering & transports ,Mechanics of Materials ,Modeling and Simulation ,Materials compostos -- Fatiga ,0210 nano-technology ,business ,Materials compostos -- Deslaminatge - Abstract
This work introduces a procedure based on the real time monitoring of the specimen's compliance for the experimental characterization of the fatigue behaviour of interlaminar cracks in composites. The methodology was applied to a mode II loading in a three-point end notch flexure test. The onset point for fatigue damage was determined with a precision of one cycle by establishing a threshold on the compliance variation from its initial value. On the other hand, the crack growth rate curve was derived from the continuous monitoring of the compliance and an experimental calibration of said compliance. The precision of this methodology allowed the effect of commonly neglected phenomena such as the thermal expansion of the testing system or the friction between the specimen and the fixture, to be unveiled This work has been funded by the Spanish Minsterio de Economía y Competitividad through the project MAT2012-37552-C03-03
- Published
- 2016
7. Smart renewable hubs: Multi-hybridization to achieve high RE penetration in a grid-friendly manner
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Alberto R. Rocha, J. M. Estebaranz, Petros Markopoulos, Rubén Durán, Francisco J. Comas, Aris Dimeas, Eduardo Cerrajero, Jorge Servert, Andrea Vaiani, Eirini Stavropoulou, and Maria Kourasi
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Flexibility (engineering) ,Wind power ,business.industry ,Computer science ,020209 energy ,02 engineering and technology ,Environmental economics ,Grid ,7. Clean energy ,Renewable energy ,Variable renewable energy ,13. Climate action ,Grid friendly ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Electricity ,business ,Operating cost - Abstract
PV and Wind energy have led the development and installation of Renewable Energy (RE) technologies worldwide, already reaching economic competitiveness against traditional fossil-fueled power plants in certain markets. However, Variable Renewable Energy or VRE is hard to control, requiring backup technologies to guarantee grid stability. The long-term target of decarbonizing the electric sector will therefore require additional flexibility and dispatchability from VRE generation. Weak and/or isolated grids, such as islands, are already dealing with these VRE limitations, with the additional burden of energy dependency leading to high electricity costs. GRIDSOL project presents a novel approach to increase RE penetration in these markets: Smart Renewable Hubs (SRH), where hybrid synchronous generators are integrated with VRE under a dynamic control system (DOME), self-regulating and providing ancillary grid services thanks to firm, flexible and mostly renewable generation on a single output, tailored to a specific location to maximize cost-effectiveness with no additional reserve required. A preliminary assessment of a Smart Renewable Hub (“HYSOL” (CSP+GT), PV and batteries) implementation is presented and compared with competing alternatives (gas turbine in open (OCGT) or combined (CCGT) cycle, PV and batteries) in an isolated grid (an island in the Mediterranean Sea), showing how GRIDSOL would reduce the overall operating cost in a high-RE scenario.
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- 2018
- Full Text
- View/download PDF
8. A new perforated core buckling restrained brace
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E. Simon, D. Piedrafita, X. Cahís, and J. Comas
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Core (optical fiber) ,Engineering ,Yield (engineering) ,Buckling ,business.industry ,Equidistant ,Structural engineering ,Dissipation ,Compression (physics) ,business ,Brace ,Finite element method ,Civil and Structural Engineering - Abstract
The Perforated Core Buckling Restrained Brace (PCBRB) is a new energy dissipation device for the seismic design of buildings. Its core consists of a perforated steel yielding plate which is guided and partially stabilized by the restraining unit. The core is mechanized to obtain two yielding lateral bands which are connected by several equidistant stabilizing bridges. The lateral bands are designed to yield to axial forces, as conventional BRBs do, so the force and the displacement at the yielding point can be calculated by the usual expressions of conventional buckling restrained braces, based on uniform strain distribution. To distribute the stabilizing bridges along the core, an expression based on Euler’s formulation is proposed. Under this formulation two types of specimens have been designed and tested (Type I and Type II) using three different loading protocols. The Type I specimens exhibited a stable response, while the Type II specimens suffered a progressive loss of compression capacity produced by the local buckling. Finally, the hysteretic behaviour of the tested braces and a large scale brace has been analysed with an FEM model which considers the interaction between the core and the encasing member. The model reproduces the hysteretic response during the first cycles and the influence of friction on the axial strain distribution along the yielding core.
- Published
- 2015
9. A new modular buckling restrained brace for seismic resistant buildings
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X. Cahís, J. Comas, D. Piedrafita, and E. Simon
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Engineering ,Buckling ,business.industry ,Earthquake resistant structures ,Structural engineering ,Dissipation ,Deformation (engineering) ,Modular design ,business ,Finite element method ,Brace ,Civil and Structural Engineering ,Seismic analysis - Abstract
This paper proposes an innovative BRB as a new energy dissipation device for earthquake resistant buildings. Its steel yielding core is modular, and this very design enables the yielding force and plastic deformation to be adjusted according to building requirements. Based on connecting several Seriated Modules, which are comprised of any constant number of Shear Basic Dissipation Units, deformation is proportional to the number of Seriated Modules and force to the number of Shear Basic Dissipation Units (on the Seriated Modules). Assembling the brace consists of sliding the greased yielding core into the restraining unit and coupling it with pins, thus providing easy inspection or replacement of the dissipation unit if required. Fully-scaled prototypes have been tested under reversal cyclic displacements and the hysteretic response has been proved stable and with a high cumulative ductility. The main parameters are the yielding force and the yielding displacement; which can be predicted with simple expressions. A methodology to design a restraining unit able to tackle of buckling by taking into account the initial sway deformation and the functional gap between the yielding core and the restraining unit is proposed. The hysteretic behavior has been simulated with conventional FEM software.
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- 2013
10. Renal development and cystic diseases
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C. Cabrera-Lopez, E. Ars, T. Marti, P. C. Harris, R. Torra, C. Clerckx, T. Migeon, Z. Chen, P. Ronco, E. Plaisier, I. J. Lamers, J. Van Reeuwijk, M. Azam, K. Boldt, M. Maria, L. Koster-Kamphuis, R. Qamar, M. Ueffing, F. P. Cremers, R. Roepman, H. H. Arts, S. Papizh, V. Dlin, I. Leontieva, K. Tutelman, R. D. Perrone, K. T. Bae, A. B. Chapman, O. Devuyst, R. T. Gansevoort, J. J. Grantham, E. Higashihara, V. E. Torres, O. Sergeyeva, W. Zhou, J. D. Blais, F. S. Czerwiec, F. Liu, Y. Liao, P. Fu, N. Casteleijn, D. Zittema, S. Bakker, W. Boertien, C. Gaillard, E. Meijer, E. Spithoven, J. Struck, R. Gansevoort, P. Robinson, P. McEwan, H. Hadimeri, A. C. M. Ong, B. Orskov, R. Peces, R. Sandford, F. Scolari, G. Walz, C. Cooke, K. O'Reilly, M. Riwanto, S. Kapoor, D. Rodriguez, I. Edenhofer, S. Segerer, R. P. Wuthrich, S. De Rechter, J. Bacchetta, M. Van Dyck, P. Evenepoel, J. De Schepper, E. Levtchenko, D. Mekahli, A. Carr, A. Makin, A. Baker, L. Obeidova, J. Stekrova, T. Seeman, A. Puchmajerova, J. Reiterova, M. Kohoutova, V. Tesar, S. Treille, J.-M. Bailly, B. Guillaume, L. Tuta, A. Stanigut, F. Botea, H. A. Jo, H. C. Park, H. Kim, M. Han, H. Huh, J. C. Jeong, K.-H. Oh, J. Yang, T. Y. Koo, Y.-H. Hwang, C. Ahn, A. Pisani, G. Remuzzi, P. Ruggenenti, E. Riccio, B. Visciano, L. Spinelli, J. I. Kim, K. M. Park, F. X. Liu, P. Rutherford, K. Smoyer-Tomic, V. Martinez Jimenez, J. Comas, E. Arcos, J. M. Diaz, S. Muray, J. Cabezuelo, J. Ballarin, T. Miyaoka, S. Morimoto, H. Kataoka, T. Mochizuki, K. Tsuchiya, A. Ichihara, and K. Nitta
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Cystic diseases ,Transplantation ,medicine.medical_specialty ,Nephrology ,business.industry ,Medicine ,business ,Intensive care medicine - Published
- 2016
11. Cardiovascular complications in CKD 5D
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M. Fusaro, M. Noale, G. Tripepi, A. D'angelo, D. Miozzo, M. Gallieni, P.-V. Study Group, M. Tsamelesvili, C. Dimitriadis, A. Papagianni, C. Raidis, G. Efstratiadis, D. Memmos, R. Mutluay, C. Konca Degertekin, U. Derici, S. M. Deger, F. Akkiyal, S. Gultekin, S. Gonen, G. Tacoy, T. Arinsoy, S. Sindel, C. Sanchez-Perales, E. Vazquez, E. Merino, P. Perez Del Barrio, F. J. Borrego, M. J. Borrego, A. Liebana, M. Krzanowski, K. Janda, P. Dumnicka, A. Krasniak, W. Sulowicz, Y.-O. Kim, S.-A. Yoon, Y.-S. Yun, H.-C. Song, B.-S. Kim, M. A. Cheong, A. Pasch, S. Farese, J. Floege, W. Jahnen-Dechent, T. Ohtake, R. Furuya, M. Iwagami, D. Tsutsumi, Y. Mochida, K. Ishioka, M. Oka, K. Maesato, H. Moriya, S. Hidaka, S. Kobayashi, A. Guedes, A. Malho Guedes, A. Pinho, A. Fragoso, A. Cruz, P. Mendes, E. Morgado, I. Bexiga, A. P. Silva, P. Neves, N. Oyake, K. Suzuki, S. Itoh, S. Yano, K. Turkmen, H. Kayikcioglu, O. Ozbek, M. Saglam, A. Toker, H. Z. Tonbul, S. Gelev, L. Trajceska, E. Srbinovska, S. Pavleska, V. Amitov, G. Selim, P. Dzekova, A. Sikole, H. Bouarich, S. Lopez, C. Alvarez, I. Arribas, P. DE Sequera, D. Rodriguez, S. Tanaka, T. Kanemitsu, M. Sugahara, M. Kobayashi, L. Uchida, Y. Ishimoto, N. Kotera, S. Tanimoto, K. Tanabe, K. Hara, T. Sugimoto, N. Mise, B. Goldstein, M. Turakhia, C. Arce, W. Winkelmayer, B. E.-D. Zayed, K. Said, M. Nishimura, Y. Okamoto, T. Tokoro, M. Nishida, T. Hashimoto, N. Iwamoto, H. Takahashi, T. Ono, N. Sato, J. Raimann, L. A. Usvyat, J. Sands, N. W. Levin, P. Kotanko, M. Iwasaki, N. Joki, Y. Tanaka, N. Ikeda, T. Hayashi, S. Kubo, T.-A. Imamura, Y. Takahashi, K. Hirahata, Y. Imamura, H. Hase, K. Claes, B. Meijers, B. Bammens, D. Kuypers, M. Naesens, Y. Vanrenterghem, P. Evenepoel, G. Boscutti, L. Calabresi, M. Bosco, S. Simonelli, E. Boer, C. Vitali, M. Martone, P. L. Mattei, G. Franceschini, E. Baligh, E. El-Shafey, A. Ezaat, A. Zawada, K. Rogacev, B. Hummel, O. Grun, A. Friedrich, B. Rotter, P. Winter, J. Geisel, D. Fliser, G. H. Heine, J.-I. Makino, K.-S. Makino, T. Ito, S. Genovesi, A. Santoro, P. Fabbrini, E. Rossi, D. Pogliani, A. Stella, G. Bonforte, G. Remuzzi, S. Bertoli, C. Pozzi, S. Pasquali, L. Cagnoli, F. Conte, I. Buzadzic, J. Tosic, N. Dimkovic, Z. Djuric, J. Popovic, I. Pejin Grubisa, N. Barjaktarevic, A. DI Napoli, D. DI Lallo, M. F. Salvatori, F. Franco, S. Chicca, G. Guasticchi, M. Onofriescu, S. Hogas, V. Luminita, A. Mugurel, V. Gabriel, F. Laura, M. Irina, C. Adrian, E. Bosch, E. Baamonde, C. Culebras, G. Perez, B. El Hayek, J. I. Ramirez, A. Ramirez, C. Garcia, M. Lago, A. Toledo, M. D. Checa, T. Taira, T. Hirano, K. Nohtomi, T. Hyodo, T. Chiba, A. Saito, Y. K. Kim, E. J. Choi, C. W. Yang, Y.-S. Kim, P. S. Lim, W. Ming Ying, J. Ya-Chung, I. Zaripova, I. Kayukov, A. Essaian, A. Nimgirova, H. Young, M. Dungey, E. L. Watson, R. Baines, J. O. Burton, A. C. Smith, K. Yamazaki, M. Bossola, L. Colacicco, D. Scribano, C. Vulpio, L. Tazza, T. Okada, N. Okada, I. Michibata, T. Yura, N. Montero, M. Soler, M. Pascual, C. Barrios, E. Marquez, E. Rodriguez, M. A. Orfila, H. Cao, E. Arcos, J. Comas, J. Pascual, M. Ferrario, F. Garzotto, T. Sironi, S. Monacizzo, F. Basso, D. N. Cruz, U. Moissl, C. Tetta, M. G. Signorini, S. Cerutti, C. Ronco, I. Mostovaya, M. Grooteman, M. Van den Dorpel, L. Penne, N. Van der Weerd, A. Mazairac, C. Den Hoedt, R. Levesque, M. Nube, P. Ter Wee, M. Bots, P. Blankestijn, J. Liu, K. L. MA, X. Zhang, B. C. Liu, I.-D. Vladu, R. Mustafa, D. Cana-Ruiu, C. Vaduva, C. Grauntanu, E. Mota, R. Singh, N. Abbasian, C. Stover, N. Brunskill, J. Burton, K. Herbert, A. Bevington, M. Wu, R.-N. Tang, M. Gao, H. Liu, L. Chen, L.-L. LV, B.-C. Liu, M. Nikodimopoulou, S. Liakos, S. Kapoulas, C. Karvounis, D. Fedak, M. Kuzniewski, D. Paulina, B. Kusnierz-Cabala, M. Kapusta, B. Solnica, A. Junque, E. S. Vicent, L. Moreno, M. Fulquet, V. Duarte, A. Saurina, M. Pou, J. Macias, M. Lavado, M. Ramirez de Arellano, M. Ryuzaki, H. Nakamoto, S. Kinoshita, E. Kobayashi, C. Takimoto, T. Shishido, G. Enia, C. Torino, R. Tripepi, V. Panuccio, M. Postorino, A. Clementi, M. Garozzo, G. Bonanno, R. Boito, G. Natale, T. Cicchetti, A. Chippari, D. Logozzo, G. Alati, S. Cassani, A. Sellaro, C. Zoccali, B. Quiroga, E. Verde, S. Abad, A. Vega, M. Goicoechea, J. Reque, J. M. Lopez-Gomez, J. Luno, C. Cabre Menendez, V. Moles, J. P. Vives, D. Villa, J. Vinas, T. Compte, M. Arruche, C. Diaz, J. Soler, J. Aguilera, A. Martinez Vea, A. De Mauri, P. David, M. M. Conte, D. Chiarinotti, C. E. Ruva, M. De Leo, A.-S. Bargnoux, M. Morena, I. Jaussent, L. Chalabi, P. Bories, J.-J. Dion, P. Henri, M. Delage, A.-M. Dupuy, S. Badiou, B. Canaud, J.-P. Cristol, E. Sironi, F. Pieruzzi, E. Galbiati, M. R. Vigano, S. Anpalakhan, S. Rocha, N. Chitalia, R. Sharma, J. C. Kaski, J. Chambers, D. Goldsmith, D. Banerjee, V. Cernaro, A. Lacquaniti, R. Lupica, S. Lucisano, M. R. Fazio, V. Donato, M. Buemi, I. Segalen, U. Vinsonneau, T. Tanquerel, G. Quiniou, Y. Le Meur, E. Seibert, M. Girndt, K. Zohles, C. Ulrich, A. Kluttig, S. Nuding, C. Swenne, J. Kors, K. Werdan, R. Fiedler, N. C. Van der Weerd, M. P. Grooteman, M. A. Van den Dorpel, M. J. Nube, J. Wetzels, D. W. Swinkels, P. M. Ter Wee, A. Khandekar, J. Khandge, J. E. Lee, S. J. Moon, K. H. Choi, H. Y. Lee, B. S. Kim, E. Tuaillon, A. Rodriguez, L. Chenine, J.-P. Vendrell, Y.-M. Sue, C.-H. Tang, Y.-C. Chen, P. Segura, M. J. Garcia Cortes, J. M. Gil, M. M. Biechy, D. Poulikakos, A. Shah, M. Persson, P. Dattolo, M. Amidone, S. Michelassi, L. Moriconi, G. Betti, P. Conti, A. Rosati, A. Mannarino, V. Panichi, F. Pizzarelli, K. Klejna, B. Naumnik, E. Koc-Zorawska, M. Mysliwiec, S. Dimitrie, H. Simona, O. Mihaela, O. Gabriela, S. Radu, P. Octavian, H. Akdam, H. Akar, Y. Yenicerioglu, O. Kucuk, I. Kurt Omurlu, S. Thambiah, R. Roplekar, P. Manghat, I. Fogelman, W. Fraser, G. Hampson, E. Likaj, G. Caco, S. Seferi, M. Rroji, M. Barbullushi, N. Thereska, A. Serban, V. Carmen, S. Cristian, L. Silvia, and A. Covic
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Transplantation ,medicine.medical_specialty ,Nephrology ,business.industry ,medicine ,Intensive care medicine ,business - Published
- 2012
12. Palaeoclimatic oscillations in the Pliensbachian (Lower Jurassic) of the Asturian Basin (Northern Spain)
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J. J. Gómez, M. J. Comas-Rengifo, and A. Goy
- Abstract
One of the main controversial items in palaeoclimatology is to elucidate if climate during the Jurassic was warmer than present day, with no ice caps, or if ice caps were present in some specific intervals. The Pliensbachian Cooling event (Lower Jurassic) has been pointed out as one of the main candidates to have developed ice caps on the poles. To constrain the timing of this cooling event, including the palaeoclimatic evolution before and after cooling, as well as the calculation of the seawater palaeotemperatures are of primary importance to find arguments on this subject. For this purpose, the Rodiles section of the Asturian Basin (Northern Spain), a well exposed succession of the uppermost Sinemurian, Pliensbachian and Lower Toarcian deposits, has been studied. A total of 562 beds were measured and sampled for ammonites, for biostratigraphical purposes and for belemnites, to determine the palaeoclimatic evolution through stable isotope studies. Comparison of the recorded uppermost Sinemurian, Pliensbachian and Lower Toarcian changes in seawater palaeotemperature with other European sections allows characterization of several climatic changes of probable global extent. A warming interval which partly coincides with a negative δ13Cbel excursion was recorded at the Upper Sinemurian. After a "normal" temperature interval, a new warming interval that contains a short lived positive δ13Cbel peak, was developed at the Lower-Upper Pliensbachian transition. The Upper Pliensbachian represents an outstanding cooling interval containing a positive δ13Cbel excursion interrupted by a small negative δ13Cbel peak. Finally, the Lower Toarcian represented an exceptional warming period pointed as the main responsible for the prominent Lower Toarcian mass extinction.
- Published
- 2015
13. Medidas de estrellas dobles
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J. Comas Solá
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Physics ,Space and Planetary Science ,Astronomy and Astrophysics - Published
- 2006
14. Demonstration of a tool for automatic learning and re-use of knowledge in the activated sludge process
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Christian Rosén, Ignasi Rodríguez-Roda, Ulf Jeppsson, Krist V. Gernaey, Manel Poch, and J Comas
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Engineering ,Nitrates ,Environmental Engineering ,Sewage ,Nitrogen ,business.industry ,Rain ,Automatic learning ,Reuse ,Models, Biological ,Waste Disposal, Fluid ,Oxygen ,Benchmarking ,Bioreactors ,Information engineering ,Risk analysis (engineering) ,Artificial Intelligence ,Numerical control ,Computer Simulation ,Case-based reasoning ,business ,Complex problems ,Simulation ,Water Science and Technology ,Intuition - Abstract
Wastewater treatment plant operators encounter complex operational problems related to the activated sludge process and usually respond to these by applying their own intuition and by taking advantage of what they have learnt from past experiences of similar problems. However, previous process experiences are not easy to integrate in numerical control, and new tools must be developed to enable re-use of plant operating experience. The aim of this paper is to investigate the usefulness of a case-based reasoning (CBR) approach to apply learning and re-use of knowledge gained during past incidents to confront actual complex problems through the IWA/COST Benchmark protocol. A case study shows that the proposed CBR system achieves a significant improvement of the benchmark plant performance when facing a high-flow event disturbance.
- Published
- 2006
15. Extension of the IWA/COST simulation benchmark to include expert reasoning for system performance evaluation
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J Comas, Christian Rosén, Ulf Jeppsson, Ignasi Rodríguez-Roda, Manel Poch, and Krist V. Gernaey
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Engineering ,Environmental Engineering ,Sewage ,business.industry ,Environmental engineering ,Expert Systems ,Benchmarking ,Models, Theoretical ,computer.software_genre ,Waste Disposal, Fluid ,Outcome (game theory) ,Fuzzy logic ,Expert system ,Reliability engineering ,Data flow diagram ,Fuzzy Logic ,Benchmark (computing) ,Computer Simulation ,Point (geometry) ,business ,Weather ,computer ,Water Science and Technology ,Waste disposal - Abstract
In this paper the development of an extension module to the IWA/COST simulation benchmark to include expert reasoning is presented. This module enables the detection of suitable conditions for the development of settling problems of biological origin (filamentous bulking, foaming and rising sludge) when applying activated sludge control strategies to the simulation benchmark. Firstly, a flow diagram is proposed for each settling problem, and secondly, the outcome of its application is shown. Results of the benchmark for two evaluated control strategies illustrate that, once applied to the simulation outputs, this module provides supplementary criteria for plant performance assessment. Therefore, simulated control strategies can be evaluated in a more realistic framework, and results can be recognised as more realistic and satisfactory from the point of view of operators and real facilities.
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- 2006
16. Evaluation of Mycoplasma hyopneumoniae growth by flow cytometry
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Raquel Diaz, P. Assunção, J. Comas, C. M. Ruiz de Galarreta, José B. Poveda, and O. R. González-Llamazares
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Bacteriological Techniques ,medicine.diagnostic_test ,biology ,Mycoplasma hyopneumoniae ,General Medicine ,Growth curve (biology) ,Ph measurement ,Flow Cytometry ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Molecular biology ,Microbiology ,Flow cytometry ,chemistry.chemical_compound ,Broth medium ,chemistry ,Nucleic acid ,medicine ,Mollicutes ,Propidium iodide ,Biotechnology - Abstract
Aims: In the present study we evaluated the potential application of the flow cytometry (FC) technique to determine the growth rates of Mycoplasma hyopneumoniae in a broth medium. Methods and Results: The FC analysis was performed using the fluorochromes Syto 9, propidium iodide (PI) or a combination of both dyes and results were compared with those obtained by colour-changing units (CCU) and pH measurements. While CCU counts ml−1 were higher than those obtained from the FC technique, a good relation between M. hyopneumoniae growth rates was observed in the different phases of the growth curve (logarithmic, stationary and senescence phases). Labelling with Syto 9 alone was sufficient to differentiate M. hyopneumoniae cells with different amounts of nucleic acids, in the stationary and senescence phase of the M. hyopneumoniae growth curve. PI labelling did not detect cell death in the end phase of M. hyopneumoniae growth. Conclusions: These data show that FC is a very useful, practical and fast technique to study the growth rates of M. hyopneumoniae in broth medium. Significance and Impact of the Study: This is to our knowledge the first application of FC to the study of M. hyopneumoniae growth in broth culture.
- Published
- 2005
17. The Aristotle score: a complexity-adjusted method to evaluate surgical results1
- Author
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J. Jacobs, W. Daenen, G. Stellin, B. Maruszsewski, T. Spray, M. Pozzi, S. Daebritz, M. Jacobs, C. Tchervenkov, Lacour-Gayet F, W. Gaynor, L. Hamilton, D. Clarke, Constantine Mavroudis, and J. Comas
- Subjects
Pulmonary and Respiratory Medicine ,Surgical results ,medicine.medical_specialty ,business.industry ,media_common.quotation_subject ,Control (management) ,Patient characteristics ,General Medicine ,Surgical procedures ,Outcome (game theory) ,Predictive value ,Surgery ,Coming out ,Medicine ,Medical physics ,Quality (business) ,Cardiology and Cardiovascular Medicine ,business ,media_common - Abstract
Objectives: Quality control is difficult to achieve in Congenital Heart Surgery (CHS) because of the diversity of the procedures. It is particularly needed, considering the potential adverse outcomes associated with complex cases. The aim of this project was to develop a new method based on the complexity of the procedures. Methods: The Aristotle project, involving a panel of expert surgeons, started in 1999 and included 50 pediatric surgeons from 23 countries, representing the EACTS, STS, ECHSA and CHSS. The complexity was based on the procedures as defined by the STS/EACTS International Nomenclature and was undertaken in two steps: the first step was establishing the Basic Score, which adjusts only the complexity of the procedures. It is based on three factors: the potential for mortality, the potential for morbidity and the anticipated technical difficulty. A questionnaire was completed by the 50 centers. The second step was the development of the Comprehensive Aristotle Score, which further adjusts the complexity according to the specific patient characteristics. It includes two categories of complexity factors, the procedure dependent and independent factors. After considering the relationship between complexity and performance, the Aristotle Committee is proposing that: Performance ¼ Complexity £ Outcome. Results: The Aristotle score, allows precise scoring of the complexity for 145 CHS procedures. One interesting notion coming out of this study is that complexity is a constant value for a given patient regardless of the center where he is operated. The Aristotle complexity score was further applied to 26 centers reporting to the EACTS congenital database. A new display of centers is presented based on the comparison of hospital survival to complexity and to our proposed definition of performance. Conclusion: A complexity-adjusted method named the Aristotle Score, based on the complexity of the surgical procedures has been developed by an international group of experts. The Aristotle score, electronically available, was introduced in the EACTS and STS databases. A validation process evaluating its predictive value is being developed. q 2004 Published by Elsevier B.V.
- Published
- 2004
18. Study of the Correlations Between Filtration Variables, Sludge Properties and Operational Conditions Via Statistical Analysisin a MBR Pilot Plant
- Author
-
J. Moreno Domingo, M. Dalmau Figueras, S. Gabarrón Fernández, J. Comas Matas, I. Rodriguez-Roda Layret, and H. Monclús Sales
- Subjects
Sludge properties ,Fouling ,Waste management ,General Medicine ,law.invention ,MBR ,Pilot plant ,Statistical analysis ,law ,Environmental science ,Engineering(all) ,Filtration - Published
- 2012
19. Assessment ofE. coli andSalmonella viability and starvation by confocal laser microscopy and flow cytometry using rhodamine 123, DiBAC4(3), propidium iodide, and CTC
- Author
-
J Comas-Riu, S Castel, Josep Vives-Rego, and R López-Amorós
- Subjects
Microscope ,medicine.diagnostic_test ,Confocal ,Biophysics ,Cell Biology ,Hematology ,Biology ,Rhodamine 123 ,Molecular biology ,Pathology and Forensic Medicine ,Flow cytometry ,law.invention ,chemistry.chemical_compound ,Endocrinology ,chemistry ,law ,Cell culture ,medicine ,Viability assay ,Propidium iodide ,Formazan - Abstract
Assessment of cell viability using methods which do not require cell culture is essential in the field of aquatic microbiology, since many bacteria known to be present in aquatic environments cannot be grown in culture. The study of bacterial biofilms, which previously needed an epifluorescent microscope, has recently been enhanced by the use of flow cytometry and confocal scanning laser microscopy (CSLM). A method based on the combination of several membrane potential related dyes, a membrane integrity dye and a redox probe was used to measure cell viability by flow cytometry and confocal laser microscopy. Rhodamine-propidium iodide (PI) double staining was used to discriminate viable from nonviable cells in CSLM observations. Membrane depolarization during E. coli and Salmonella starvation measured by DiBAC4(3) incorporation (flow cytometry and CSLM) was found to be in concordance with respiratory activity as detected by a tetrazolium salt (CTC) reduction.
- Published
- 1997
20. Wildfire, wildlands, and people: understanding and preparing for wildfire in the wildland-urban interface - a Forests on the Edge report
- Author
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S. J. Comas, J. Menakis, S. I. Stewart, M. A. Carr, H. Cleveland, V. C. Radeloff, L. Bramwell, and S. M. Stein
- Subjects
Wildfire suppression ,Defensible space ,Community planning ,Environmental science ,Wildland–urban interface ,Enhanced Data Rates for GSM Evolution ,Environmental planning - Published
- 2013
21. Scaling of the nonlinear optical cross sections of GaAs-AlGaAs multiple quantum-well hetero n-i-p-i's
- Author
-
J. Comas, W.F. Tseng, Arthur L. Smirl, J.G. Pellegrino, D. S. McCallum, and Alexander N. Cartwright
- Subjects
Physics ,business.industry ,Nonlinear optics ,Photorefractive effect ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Molecular physics ,Fluence ,Atomic and Molecular Physics, and Optics ,Gallium arsenide ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Stark effect ,symbols ,Optoelectronics ,Electrical and Electronic Engineering ,Absorption (electromagnetic radiation) ,business ,Scaling ,Quantum well - Abstract
We study the dependence of the Stark shift optical nonlinearity of GaAs-AlGaAs multiple quantum-well hetero n-i-p-i's on the number of quantum wells per intrinsic region in otherwise identical hetero n-i-p-i's. We determine that /spl sigma//sub eh/, the nonlinear absorption cross section, is proportional to the number of quantum wells per intrinsic region. A study of the fluence dependence of /spl sigma//sub eh/ shows that the saturation carrier density is inversely proportional to the number of wells per intrinsic region. We find that the turn-on time of the nonlinear absorption change in our samples is independent of the number of quantum wells per intrinsic region. All of these results are consistent with the absence of retrapping of photogenerated carriers. >
- Published
- 1994
22. Defects in III–V materials and the accommodation of strain in layered semiconductors
- Author
-
W. F. Tseng, Krishna Rajan, Ronald C. Dobbyn, J. Comas, Bruce Steiner, and Uri Laor
- Subjects
Dislocation creep ,Materials science ,Condensed matter physics ,business.industry ,Heterojunction ,Condensed Matter Physics ,Epitaxy ,Electronic, Optical and Magnetic Materials ,Gallium arsenide ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,Optics ,Semiconductor ,chemistry ,Materials Chemistry ,Indium phosphide ,Partial dislocations ,Electrical and Electronic Engineering ,Dislocation ,business - Abstract
High resolution monochromatic synchrotron-radiation diffraction images of five, high quality epitaxial heterojunctions on silicon, gallium arsenide, and indium phosphide substrates display several forms of accommodation to lattice mismatch. From the images, we deduce a coherent set of factors for the loss of crystalline order in layered semiconducting crystals. Lattice mismatch is demonstrated in each of the systems by warping after layer deposition. Nevertheless, local lattice orientation is maintained across each layer interface. In two of the systems, one severely mismatched while the other is not, no arrays of dislocations appear. Sets of mixed linear lattice mismatch dislocations, consistent with identification as 60° dislocations, are found in two of the other systems with intermediate degrees of mismatch. A set of pure edge dislocations penetrating all layers is found in a system with a grid structure. These observations indicate that the formation of extensive arrays of dislocations during uniform one micrometer layer deposition depends not only on the extent of lattice mismatch and layer thickness but also on the degree of crystalline order of the substrate. Establishment of a nonpseudomorphic layer mismatched with the substrate by several tenths of a percent is an important factor, as previously determined. However, localized absence of crystalline order, e.g. in the form of scratches or dislocations in the substrate, appears also to be required for the formation of arrays of interface mismatch dislocations. Where these criteria are not fulfilled, the formation of dislocations in uniform layered systems is inhibited. Localized residual stress can initiate dislocation formation even where it would not appear in uniform layers. The images show also that crystalline disorder in state-of-the-art indium phosphide differs markedly from that in comparable gallium arsenide. Understanding of crystalline order in both monolithic materials is extended by this work.
- Published
- 1993
23. Rapid-thermal annealing for quantum-well heterostructure device fabrication
- Author
-
Abhaya K. Datye, L. R. Dawson, Gregory A. Vawter, I. J. Fritz, David R. Myers, T.J. Drummond, D. S. Simons, J. Comas, Eric D. Jones, Thomas M. Brennan, Thomas E. Zipperian, and B. E. Hammons
- Subjects
Photoluminescence ,Materials science ,Fabrication ,Condensed Matter::Other ,business.industry ,Transistor ,technology, industry, and agriculture ,Heterojunction ,Semiconductor device ,equipment and supplies ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electronic, Optical and Magnetic Materials ,law.invention ,Condensed Matter::Materials Science ,Ion implantation ,law ,Optoelectronics ,Field-effect transistor ,Electrical and Electronic Engineering ,business ,Quantum well - Abstract
The authors examine ion implantation and rapid-thermal processing for the fabrication of quantum-well, compound-semiconductor heterostructure devices in strained and in lattice-matched material systems. The authors demonstrate improvements to the performance of two classes of devices that would be particularly sensitive to process-induced defects: p-channel strained-quantum-well field-effect transistors and single-quantum-well diode lasers. The authors correlated the device results with secondary-ion mass spectroscopy, Hall-effect, transmission-electron microscopy, and photoluminescence. >
- Published
- 1992
24. Innovación como cambio institucional: Una aproximación desde las teorías de la complejidad
- Author
-
J. Comas Trayter, L. Prats Planagumá, and J. Guia Julve
- Subjects
innovation process ,Economics and Econometrics ,Process (engineering) ,Strategy and Management ,Control (management) ,Complejidad ,institutional change ,Innovation management ,lcsh:Business ,Organizational context ,ddc:330 ,Cambio institucional ,Sociology ,Business and International Management ,Proceso de innovación ,Innovation ,Innovation process ,Marketing ,Institutional change ,Perspective (graphical) ,Complexity ,innovation ,Management ,Epistemology ,Innovación ,Position (finance) ,lcsh:HF5001-6182 ,complexity - Abstract
RESUMENUno de los temas más controvertidos dentro de la literatura sobre gestión de la innovación es el grado en que estos procesos son controlables y planificables. Esta literatura ha evolucionado desde una posición racional dentro de la cual los procesos de innovación son el resultado de decisiones racionales, intencionadas y debidamente planificadas, a una posición más evolutiva en la cual si bien no es posible controlar y gestionar el proceso directamente, si que lo es controlar el las condiciones del contexto organizativo de la innovación con objeto de incrementar el éxito del proceso. En este artículo, analizamos el proceso de innovación desde un nuevo paradigma que va más allá de los anteriores y que se fundamenta en los postulados de las teorías de la complejidad y en la asimilación de los procesos de innovación a los procesos de cambio institucional. Desde esta nueva perspectiva, se deduce que los procesos de innovación y el cambio institucional consiguiente tienen una base pragmática y, en consecuencia, el potencial para la planificación y control de los procesos de innovación se ve altamente limitado.ABSTRACTOne of the most controverted subjects in the literature on innovation management is the extent to which these processes can be controlled and planned. This literature has evolved from a rational position in which the innovation processes are the result of rational decisions, deliberate and properly planned, to a more evolutionary approach. From this evolutionary perspective the control and management of the process is made indirectly by controlling and intervening on the organizational context of the process of innovation process. In this article, we analyze the innovation process from the perspective of a new paradigm that goes beyond the previous two. It lies on the postulates of the complexity theories and takes the processes of innovation as processes of institutional change. From this new perspective, we deduce that the processes of innovation and the consequent institutional change have a pragmatic basis, and consequently, the potential for the planning and control of the innovation processes is seen highly limited.
- Published
- 2009
25. La calidad en educación superior o la otra cara del conflicto entre organización e institución universitarias
- Author
-
Óscar J. Comas Rodríguez
- Subjects
Educación ,Calidad en educación superior Institución Organización y estímulos económicos ,lcsh:L ,lcsh:L7-991 ,lcsh:Education (General) ,lcsh:Education - Abstract
Este artículo presenta una visión del concepto de calidad de la educación superior que ha prevalecido en México a partir de las políticas públicas modernizadoras que ha implementado el gobierno federal. Se centra en el análisis de la transformación de la institución universitaria a la organización universitaria y enfatiza dos de los principales instrumentos que han acelerado dicho proceso: los estímulos para los docentes y el Programa de Fortalecimiento Institucional (PIFI) para las instituciones. Concluye que la organización universitaria es un objeto que se adapta y asume la transformación primordialmente porque detrás de ella se encuentra el financiamiento para desarrollar las funciones sustantivas de la Universidad.
- Published
- 2007
26. National forests on the edge: development pressures on America's national forests and grasslands
- Author
-
Susan M. Stein, Ralph J. Alig, Eric M. White, Sara J. Comas, Mary Carr, Mike Eley, Kelly Elverum, Mike O'Donnell, David M. Theobald, Ken Cordell, Jonathan Haber, and Theodore W. Beauvais
- Subjects
Geography ,Land use ,Agroforestry ,business.industry ,Amenity ,Environmental resource management ,Land use, land-use change and forestry ,National forest ,business ,Economic benefits ,Housing density ,Subdivision ,Ecosystem services - Abstract
Many of America’s national forests and grasslands—collectively called the National Forest System—face increased risks and alterations from escalating housing development on private rural lands along their boundaries. National forests and grasslands provide critical social, ecological, and economic benefits to the American public. This study projects future housing density increases on private rural lands at three distances—2, 3, and 10 miles—from the external boundaries of all national forests and grasslands across the conterminous United States. Some 21.7 million acres of rural private lands (about 8 percent of all private lands) located within 10 miles of the National Forest System boundaries are projected to undergo increases in housing density by 2030. Nine national forests are projected to experience increased housing density on at least 25 percent of adjacent private lands at one or more of the distances considered. Thirteen national forests and grasslands are each projected to have more than a half-million acres of adjacent private rural lands experience increased housing density. Such development and accompanying landscape fragmentation pose substantial challenges for the management and conservation of the ecosystem services and amenity resources of National Forest System lands, including access by the public. Research such as this can help planners, managers, and communities consider the impacts of local land use decisions.
- Published
- 2007
27. Evaluating the application of a decision support system in identifying adequate wastewater treatment for small communities. A case study: the Fluvia River Basin
- Author
-
J, Alemany, J, Comas, C, Turon, M D, Balaguer, M, Poch, M A, Puig, and J, Bou
- Subjects
Technology ,Rivers ,Residence Characteristics ,Spain ,Cities ,Waste Disposal, Fluid ,Decision Support Techniques - Abstract
The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.
- Published
- 2005
28. The Aristotle score: a complexity-adjusted method to evaluate surgical results
- Author
-
F, Lacour-Gayet, D, Clarke, J, Jacobs, J, Comas, S, Daebritz, W, Daenen, W, Gaynor, L, Hamilton, M, Jacobs, B, Maruszsewski, M, Pozzi, T, Spray, G, Stellin, C, Tchervenkov, and C, Mavroudis And
- Subjects
Heart Defects, Congenital ,Quality Control ,Treatment Outcome ,Databases, Factual ,Quality Assurance, Health Care ,Software Design ,International Cooperation ,Humans ,Hospital Mortality ,Cardiac Surgical Procedures ,Pediatrics ,Risk Assessment - Abstract
Quality control is difficult to achieve in Congenital Heart Surgery (CHS) because of the diversity of the procedures. It is particularly needed, considering the potential adverse outcomes associated with complex cases. The aim of this project was to develop a new method based on the complexity of the procedures.The Aristotle project, involving a panel of expert surgeons, started in 1999 and included 50 pediatric surgeons from 23 countries, representing the EACTS, STS, ECHSA and CHSS. The complexity was based on the procedures as defined by the STS/EACTS International Nomenclature and was undertaken in two steps: the first step was establishing the Basic Score, which adjusts only the complexity of the procedures. It is based on three factors: the potential for mortality, the potential for morbidity and the anticipated technical difficulty. A questionnaire was completed by the 50 centers. The second step was the development of the Comprehensive Aristotle Score, which further adjusts the complexity according to the specific patient characteristics. It includes two categories of complexity factors, the procedure dependent and independent factors. After considering the relationship between complexity and performance, the Aristotle Committee is proposing that: Performance = Complexity x Outcome.The Aristotle score, allows precise scoring of the complexity for 145 CHS procedures. One interesting notion coming out of this study is that complexity is a constant value for a given patient regardless of the center where he is operated. The Aristotle complexity score was further applied to 26 centers reporting to the EACTS congenital database. A new display of centers is presented based on the comparison of hospital survival to complexity and to our proposed definition of performance.A complexity-adjusted method named the Aristotle Score, based on the complexity of the surgical procedures has been developed by an international group of experts. The Aristotle score, electronically available, was introduced in the EACTS and STS databases. A validation process evaluating its predictive value is being developed.
- Published
- 2003
29. Study of the Correlations Between Filtration Variables, Sludge Properties and Operational Conditions Via Statistical Analysisin a MBR Pilot Plant
- Author
-
Fernández, S. Gabarrón, primary, Figueras, M. Dalmau, additional, Domingo, J. Moreno, additional, Sales, H. Monclús, additional, Layret, I. Rodriguez-Roda, additional, and Matas, J. Comas, additional
- Published
- 2012
- Full Text
- View/download PDF
30. Variations in flow cytometric forward scatter signals and cell size in batch cultures of Escherichia coli
- Author
-
J. Comas, José Vives-Rego, R. López-Amorós, and C. Carulla
- Subjects
Time Factors ,Light ,Forward scatter ,Scanning electron microscope ,Flow (psychology) ,Analytical chemistry ,Biology ,medicine.disease_cause ,Microbiology ,Cell size ,law.invention ,Flow cytometry ,law ,Genetics ,medicine ,Escherichia coli ,Image Processing, Computer-Assisted ,Scattering, Radiation ,Molecular Biology ,Incubation ,Cell Size ,medicine.diagnostic_test ,Reproducibility of Results ,Flow Cytometry ,Microscopy, Electron, Scanning ,Electron microscope - Abstract
Flow cytometry was used to study the lag, exponential, stationary and death phases of non-fixed cultures of Escherichia coli. Fluctuations in the forward angle scatter signal (FALS) were compared with cell size as measured by scanning electron microscopy at low temperature and image analysis. A correlation between FALS and cell size was not observed, although a correlation (r = −0.8) was obtained between FALS and the age of the culture for the first eleven days of incubation. Marked increases in FALS were observed during the lag phase, which were attributed both to changes in size and changes in structure or chemical composition. The distribution of FALS for all culture phases was asymmetric, and was associated with the cell size distribution.
- Published
- 1994
31. Comparison of different types of cardioplegia and reperfusion on myocardial metabolism and free radical activity
- Author
-
O, Bical, M F, Gerhardt, D, Paumier, D, Gaillard, J, Comas, P, Landais, M, Fischer, F, Trivin, and A, Vanetti
- Subjects
Cold Temperature ,Blood ,Free Radicals ,Adenine Nucleotides ,Malondialdehyde ,Myocardium ,Heart Arrest, Induced ,Humans ,Myocardial Reperfusion ,Myocardial Reperfusion Injury ,Prospective Studies ,Middle Aged ,Cardioplegic Solutions - Abstract
Current techniques of myocardial protection during global ischemia include hypothermia, cardioplegic arrest and controlled reperfusion. To compare different types of cardioplegia and reperfusion techniques we measured the levels of adenine nucleotides and malondialdehyde (MDA, as free radical activity) in 33 patients undergoing heart surgery. The patients were randomized in three groups according to the characteristics of cardioplegia and reperfusion: cold blood cardioplegia with unmodified blood reperfusion (control group, 11 patients), crystalloid cardioplegia and reperfusion (Hôpital Lariboisière protocol, 11 patients) and crystalloid cardioplegia with allopurinol enriched blood reperfusion (Hôpital Broussais protocol, 11 patients). Myocardial biopsy specimens were obtained before cardioplegic arrest (preischemic values), at the end of ischemia and after 30 minutes of reperfusion. Biopsy specimens were analyzed by high performance liquid chromatography for levels of adenine nucleotides and MDA. In the three groups, the preischemic values of adenine nucleotides and MDA were not significantly different. For AMP and ADP concentrations neither treatment nor biopsy-time effects appeared. ATP concentration decreased significantly with biopsy-time without specific treatment effect. For MDA concentration neither treatment nor biopsy-time effects were observed. This study suggests that there is no statistically significant difference between any of the three cardioplegia and reperfusion techniques for either ATP or MDA; the three reperfusion techniques limit the free radical activity but do not prevent the fall in high energy phosphates.
- Published
- 1991
32. Medidas de estrellas dobles
- Author
-
Solá, J. Comas, primary
- Published
- 2006
- Full Text
- View/download PDF
33. Les taches blanches de Saturne.
- Author
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Solá, J. Comas
- Published
- 1903
- Full Text
- View/download PDF
34. Saturne 1901.
- Author
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Solá, J. Comas
- Published
- 1902
- Full Text
- View/download PDF
35. Observations de Jupiter. Opposition de 1901.
- Author
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Solá, J. Comas
- Published
- 1902
- Full Text
- View/download PDF
36. Les fluctuations d'éclat de la Nova (3.1901) Persei.
- Author
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Sold, J. Comas
- Published
- 1901
- Full Text
- View/download PDF
37. Medidas de estrellas dobles.
- Author
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Solá, J. Comas
- Published
- 1900
- Full Text
- View/download PDF
38. Observaciones de Júpiter durante la Oposición de 1900.
- Author
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Solá, J. Comas
- Published
- 1900
- Full Text
- View/download PDF
39. El eclipse de Sol del 28 mayo 1900.
- Author
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Solá, J. Comas
- Published
- 1900
- Full Text
- View/download PDF
40. Observations des taches de Jupiter.
- Author
-
Solá, J. Comas
- Published
- 1899
- Full Text
- View/download PDF
41. Observations de Jupiter dans l'opposition de 1899.
- Author
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Solá, J. Comas
- Published
- 1899
- Full Text
- View/download PDF
42. Mesures d'étoiles multiples.
- Author
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Sold, J. Comas
- Published
- 1899
- Full Text
- View/download PDF
43. Triangulation micrométrique de l'amas 6523 (M. 8).
- Author
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Solà, J. Comas
- Published
- 1899
- Full Text
- View/download PDF
44. Observations sur le satellite III de Jupiter.
- Author
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Solá, J. Comas
- Published
- 1907
- Full Text
- View/download PDF
45. Mitteilungen über Kleine Planeten.
- Author
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Wolf, M., Sola, J. Comas, Astron, Berberich, A., and Thiele, H.
- Published
- 1915
- Full Text
- View/download PDF
46. Observation of coupled quasi-two-dimensional electronic excitations in tilted magnetic fields
- Author
-
J. Comas, Roberto Merlin, R. Borroff, and R.L. Greene
- Subjects
Physics ,Condensed matter physics ,Condensed Matter::Other ,Scattering ,Surfaces and Interfaces ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Spectral line ,Surfaces, Coatings and Films ,Magnetic field ,Coupling (physics) ,Tilt (optics) ,Materials Chemistry ,Perpendicular ,Quantum well - Abstract
We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAs/Al x Ga 1−x As quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited electrons and ls→ls′ donor excitations. Tilted fields lead to subband-Landau level and ls′−2p + coupling. Experimental results for the latter case agree very well with variational calculations. Data on combined intersubband-cyclotron resonances at arbitrary tilt angles are accurately described by expressions valid for parabolic wells. The parabolic approach is shown to provide a good approximation in situations where coupling to higher subbands can be neglected.
- Published
- 1988
47. Electronic raman scattering in quantum wells: Coupled levels in tilted magnetic fields
- Author
-
J. Comas, Roberto Merlin, R.L. Greene, and R. Borroff
- Subjects
Physics ,Condensed matter physics ,Condensed Matter::Other ,Scattering ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Spectral line ,Magnetic field ,symbols.namesake ,Coupling (physics) ,symbols ,Perpendicular ,General Materials Science ,Electrical and Electronic Engineering ,Raman scattering ,Quantum well - Abstract
We report on a magneto-Raman scattering investigation of free and donor-bound electrons in GaAsAl x Ga 1−x As quantum wells. For fields perpendicular to the layers, the spectra show intersubband transitions of photoexcited electrons and 1s → 1s′ donor excitations. Tilted fields lead to subband-Landau level and 1s′ − 2p + coupling. Experimental results for the latter case agree very well with variational calculations. Data on combined intersubband-cyclotron resonances at arbitrary tilt angles are accurately described by expression valid for parabolic wells. The parabolic approach is shown to provide a good approximation in situations where coupling to higher subbands can be neglected.
- Published
- 1987
48. Annealing studies of Be-implanted GaAs0.6P0.4
- Author
-
J. Comas, L. Plew, W. V. McLevige, K. V. Vaidyanathan, and B. G. Streetman
- Subjects
Materials science ,Low fluence ,Solid-state physics ,Annealing (metallurgy) ,Analytical chemistry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Secondary ion mass spectrometry ,Ion implantation ,Hall effect ,Electrical resistivity and conductivity ,Materials Chemistry ,Electrical and Electronic Engineering ,Ternary operation - Abstract
Differential resistivity and Hall effect measurements and secondary ion mass spectrometry (SIMS) are used to study the annealing behavior of Be-implanted GaAs0.6P0.4. Results similar to that previously reported for Be-implanted GaAs are observed, including outdiffusion of Be into the Si3N4 encapsulant during 900‡C annealing of high dose implants. Nearly all (85–100%) of the Be remaining after a 900‡C, 1/2 hr anneal is electrically active. However, the electrical activation at low annealing temperatures (600–700‡C) is much lower in GaAs0.6P0.4 than in GaAs. A substantial amount of diffusion is observed even for the low fluence Be implants in GaAs0.6P0.4 annealed at 900‡C, indicating a greater dependence of the diffusion on defect-related effects in the ternary.
- Published
- 1978
49. A comparison between atomic concentration profiles and defect density profiles in GaAs annealed after implantation with beryllium
- Author
-
J. M. Ess, M. A. Littlejohn, J. Comas, K. S. Lee, and R. B. Benson
- Subjects
Materials science ,Solid-state physics ,Annealing (metallurgy) ,Analytical chemistry ,chemistry.chemical_element ,Electron ,Condensed Matter Physics ,Fluence ,Electronic, Optical and Magnetic Materials ,Ion ,Secondary ion mass spectrometry ,Ion implantation ,chemistry ,Materials Chemistry ,Electrical and Electronic Engineering ,Beryllium - Abstract
Semi-insulating chromium-doped GaAs was implanted with 100 keV Be ions to fluences of 5 × 1013 and 1 × 1015 ions/cm2. Specimens were annealed at 800°C for thirty minutes. Beryllium atomic concentration profiles, as determined by secondary ion mass spectrometry (SIMS), were compared to the defect density profiles obtained from transmission electron stereomicroscopy techniques for the annealed samples. A major redistribution of Be was observed compared to the as-implanted distribution after annealing at the higher fluence, whereas only a slight redistribution of Be occurred for the lower fluence. A major difference in the defect density profiles was observed with the fluences used for this study in the region where the annealed specimens were compared. The distribution of defects throughout the implanted-annealed layer was examined in GaAs annealed after implantation with the higher fluence using sectioned specimens. The relationships between the atomic Be concentration profile, the defect density profile, and the distribution of some specific defects were compared in these sectioned layers. The distribution and size of defects appear to be directly influenced by the Be concentration and its associated implantation induced damage.
- Published
- 1980
50. Beryllium and sulfur ion-implanted profiles in gaas
- Author
-
Larry Plew and J. Comas
- Subjects
Materials science ,Annealing (metallurgy) ,Analytical chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Sulfur ,Fluence ,Electronic, Optical and Magnetic Materials ,Peak concentration ,Ion ,Secondary ion mass spectrometry ,chemistry ,Materials Chemistry ,Electrical and Electronic Engineering ,Solubility ,Beryllium - Abstract
Atomic profiles of ion-implanted Be and S in GaAs have been measured as a function of implant fluence and annealing temperature. Concentration versus depth profiles were ob-tained by means of secondary ion mass spectrometry (SIMS) techniques. Pyrolytically deposited and sputter-coated Si02 and Si3N4 films were used as encapsulants for the 500 to 900° annealing study. Semi-insulating GaAs was implanted with 200 keV34S+ to fluences of 1 × 1014 and 52× 1014/cm2, and 100 keV9Be+ in the 1 × 1013 to 1 × 1015/cm2 fluence range. The S profiles did not change significantly after annealing at 800°C, although there was some skewing after annealing above 600°C. In contrast, the Be profiles showed significant changes and a decrease in the peak concentration for the ≥ 5 × 10T4/cm2 implants after a 700°C anneal. After a 800°C anneal the Be profile was essentially flat with a monotonic decrease from the surface into the implanted re-gion and a 900°C anneal caused a further decrease in the Be concentration. Profiles of Be implants of ≤ 1 × 1014/cm2 did not change significantly after annealing indicating that the higher fluence cases were related to solubility effects.
- Published
- 1976
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