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Search Results: 1 - 10 of 363487 matches for " Juan Manuel Peralta-Sánchez "
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Mirror-Mark Tests Performed on Jackdaws Reveal Potential Methodological Problems in the Use of Stickers in Avian Mark-Test Studies
Manuel Soler, Tomás Pérez-Contreras, Juan Manuel Peralta-Sánchez
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086193
Abstract: Some animals are capable of recognizing themselves in a mirror, which is considered to be demonstrated by passing the mark test. Mirror self-recognition capacity has been found in just a few mammals having very large brains and only in one bird, the magpie (Pica pica). The results obtained in magpies have enormous biological and cognitive implications because the fact that magpies were able to pass the mark test meant that this species is at the same cognitive level with great apes, that mirror self-recognition has evolved independently in the magpie and great apes (which diverged 300 million years ago), and that the neocortex (which is not present in the bird's brains) is not a prerequisite for mirror self-recognition as previously believed. Here, we have replicated the experimental design used on magpies to determine whether jackdaws (Corvus monedula) are also capable of mirror self-recognition by passing the mark test. We found that our nine jackdaws showed a very high interest towards the mirror and exhibited self-contingent behavior as soon as mirrors were introduced. However, jackdaws were not able to pass the mark test: both sticker-directed actions and sticker removal were performed with a similar frequency in both the cardboard (control) and the mirror conditions. We conclude that our jackdaws' behaviour raises non-trivial questions about the methodology used in the avian mark test. Our study suggests that the use of self-adhesive stickers on sensitive throat feathers may open the way to artefactual results because birds might perceive the stickers tactilely.
Antimicrobial Activity and Genetic Profile of Enteroccoci Isolated from Hoopoes Uropygial Gland
Magdalena Ruiz-Rodríguez, Eva Valdivia, Manuel Martín-Vivaldi, Antonio M. Martín-Platero, Manuel Martínez-Bueno, María Méndez, Juan M. Peralta-Sánchez, Juan J. Soler
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041843
Abstract: Symbiotic microorganisms may be directly transferred from parents to offspring or acquired from a particular environment that animals may be able to select. If benefits for hosts vary among microbial strains, natural selection may favour hosts holding the most beneficial one. Enterococci symbionts living in the hoopoe (Upupa epops) uropygial gland are able to synthesise bacteriocins (antimicrobial peptides that inhibit the growth of competitor bacteria). We explored variability in genetic profile (through RAPD-PCR analyses) and antimicrobial properties (by performing antagonistic tests against ten bacterial indicator strains) of the different isolates obtained from the uropygial glands of hoopoe females and nestlings. We found that the genetic profile of bacterial isolates was related to antimicrobial activity, as well as to individual host identity and the nest from which samples were obtained. This association suggest that variation in the inhibitory capacity of Enterococci symbionts should be under selection.
Viabilidade do uso de argilas cauliníticas do Quadrilátero Ferrífero para a indústria ceramica
Peralta-Sánchez, M. G.;Morales-Carrera, A. M.;Varaj?o, A. F. D. C.;Ferreira, M. M.;
Ceramica , 2011, DOI: 10.1590/S0366-69132011000300002
Abstract: seven samples from three kaolin deposits of the quadrilátero ferrífero were characterized by physical, mineralogical and chemical analyses in order to determine their use in the ceramic industry. despite the predominant presence of kaolinite, the variations in the fe2o3 content from 2 to 44%, due to presence of goethite and hematite, resulted in different colors, namely: white (acm and db), yellow (r5), yellowed red (fs) and red (dv, r1 and am). specimens were burned at 900 and 1100 °c and they almost didn't change color. however, only specimens made with dv and r1 samples reached the technical specifications for the ceramic industry, without fractures and with values of compression strength of 96.2 and 64.2 mpa, respectively. the other samples were made by mixing phyllite in the proportions of 5, 10, 15, 20 and 25% and burned at 900 and 1100 °c. the bricks made with acm+15f, db+5f, r5+5f, fs+5f, am+5f and burned at 900 oc reached the technical specifications for ceramic industry, without fractures and with values of compression strength between 69.15 and 29.6 mpa.
Transforma??es mineralógicas e cristaloquímicas decorrentes dos ensaios termais em argilas cauliníticas ferruginosas
Ferreira, M. M.;Varaj?o, A. F. D. C.;Morales-Carrera, A. M.;Peralta-Sánchez, M. G.;Costa, G. M. da;
Ceramica , 2012, DOI: 10.1590/S0366-69132012000100017
Abstract: mineralogical and crystallochemical transformations of representative ferruginous kaolinitic clay samples were investigated in specimens burned at 800, 1000 and 1200 °c. x-ray diffraction and differential thermal and thermogravimetric analyses showed that kaolinite was the predominant mineral in the raw samples. the m?ssbauer spectroscopy results showed that the high iron content (22.5 wt.%), as determined by x-ray fluorescence, is related to the presence of goethite (18 wt.%) and hematite (16 wt.%). however, after fe was extracted using a dithionite-citrate system buffered with sodium bicarbonate, a residue of this element (fe3+ and fe2+) was found in the structure of the kaolinite. the sintering process showed the destruction of kaolinite, as well as the transformation of the goethite into hematite, the crystals growing as the temperature increases. the hematite crystal size at 1200 °c is five times larger than in the raw sample. the mullite formation at 1000 °c is comprised of a solid solution of fe2o3 and al2o3, which results in a resistant product with a higher thermal stability.
Terapia celular en enfermedades renales y cardiovasculares
Senior Sánchez,Juan Manuel;
Iatreia , 2006,
Abstract: although there have been important advances in the field of molecular biology, the mechanisms responsible for nephrogenesis and the factors that modulate the process of development, proliferation, growth, and maturation during fetal and adult life have not been thoroughly explained. animals, including mammals, share the intrinsic ability to regenerate tissues and organs as an important biological defense mechanism. in the case of the kidney, after tissue damage secondary to injury, anatomical and functional recovery of integrity is achieved, accompanied by the activation of a complex, poorly understood process, leading to the replacement of damaged tubular cells by functional ones that reorganize tubular architecture. this regeneration and repair process is produced by somatic, exogenous, adult stem cells, and probably by intrinsic renal stem cells, that are responsible for maintaining renal homeostasis
La didáctica de la historia en la Universidad de Quintana Roo. Un estudio de caso: el rescate del Medioevo y su influencia en el siglo XVI Novohispano
Espinosa Sánchez, Juan Manuel;
Argumentos (México, D.F.) , 2010,
Abstract: in the course of universal history ii at the university of quintana roo in the 7th semester of the bachelors program of humanities during the summer of 2007 students were given to read the historical novel from umberto eco in the name of the rose. this was done with didactic purposes in order to introduce the students to the middle ages and to teach them which specific part of this era and culture arrived in the new spain in the xvi century; i.e. scholastic philosophy, the castilian language, the latin language, and the catholic religion among other cultural aspects. it is important to consider that many of our students come not only from urban areas but from rural ones as well and in many cases they have a mayan background and many of them even speak the mayan language. this is one of the most important aspects to be considered while teaching courses of this nature; for many students this will be their first time encountering with this sort of knowledge new to them since it is not taught in any previous educational levels in the state of quintana roo, mexico.
Cardiovascular disfunction during sepsis Disfunción cardiovascular en sepsis
Juan Manuel Senior Sánchez
Iatreia , 1996,
Abstract: A review is presented on some aspects of sepsis, with emphasis on cardiovascular alterations; the following subjects are included: reasons for increasing frequency of sepsis, up to date terminology, diagnostic criteria, pathogenesis, manifestations of cardiovascular disfunction, present day therapy and therapeutic perspectives. Se hace una revisión somera de algunos aspectos de la sepsis con énfasis en los cambios cardiovasculares que tienen lugar durante ella; se incluyen los siguientes: razones para el incremento de la frecuencia, terminología, criterios de diagnóstico, patogénesis,manifestaciones de la disfunción cardiovascular, terapia actual y perspectivas terapéuticas.
Cell therapy in renal and cardiovascular disease Terapia celular en enfermedades renales y cardiovasculares
Juan Manuel Senior Sánchez
Iatreia , 2006,
Abstract: Although there have been important advances in the field of molecular biology, the mechanisms responsible for nephrogenesis and the factors that modulate the process of development, proliferation, growth, and maturation during fetal and adult life have not been thoroughly explained. Animals, including mammals, share the intrinsic ability to regenerate tissues and organs as an important biological defense mechanism. In the case of the kidney, after tissue damage secondary to injury, anatomical and functional recovery of integrity is achieved, accompanied by the activation of a complex, poorly understood process, leading to the replacement of damaged tubular cells by functional ones that reorganize tubular architecture. This regeneration and repair process is produced by somatic, exogenous, adult stem cells, and probably by intrinsic renal stem cells, that are responsible for maintaining renal homeostasis Aunque se han logrado grandes avances en el campo de la biología molecular, todavía no se han esclarecido completamente los mecanismos responsables de la organogénesis y los factores que modulan el proceso de desarrollo, proliferación, crecimiento y maduración celulares durante la vida fetal y adulta. Los animales comparten la capacidad de regenerar tejidos y órganos, como un mecanismo biológico importante de defensa. En el caso del ri ón, luego del da o tisular secundario a una noxa, se produce recuperación anatómica y funcional de la integridad, acompa ada por la activación de un proceso sofisticado, mal comprendido, que lleva al reemplazo de las células tubulares da adas por otras funcionalmente normales que reorganizan la arquitectura tubular. Este fenómeno de recambio se produce gracias a la presencia de células madre adultas somáticas exógenas, responsables del proceso de mantenimiento de la homeostasis renal, y posiblemente por células renales intrínsecas.
La racionalidad delirante: el racismo científico en la segunda mitad del siglo XIX.
Juan Manuel Sánchez Arteaga
Revista de la Asociación Espa?ola de Neuropsiquiatría , 2007,
Abstract: Una crítica epistemológica a la idea neopositivista de ‘racionalidad científica’ a partir de un análisis del racismo implícito en los conceptos científicos ortodoxos sobre la diversidad biológica humana durante el periodo de aceptación de las tesis darwinistas sobre el origen evolutivo de nuestra especie.
Un repaso rápido de botánica de forrajes (cuento didáctico) - A review fast of forage botany (didactic tale)
Cervantes Sánchez, Juan Manuel.
REDVET , 2011,
Abstract: ResumenLos cuentos didácticos son una pieza básica en la consecución de losobjetivos educativos, son, así mismo, complemento a las diferentesactividades educativas. Tiene como finalidad introducirá al estudiante en un área muy bien definida del conocimiento, en un corto tiempo.SummaryThe didactic stories are a basic piece in the attainment of the educative objectives, are, also, complement to the different educative activities.
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