2,919 research outputs found

    Tools and Biomarkers for the Study of Retinal Ganglion Cell Degeneration

    Get PDF
    The retina is part of the central nervous system, its analysis may provide an idea of the health and functionality, not only of the retina, but also of the entire central nervous system, as has been shown in Alzheimer"s or Parkinson"s diseases. Within the retina, the ganglion cells (RGC) are the neurons in charge of processing and sending light information to higher brain centers. Diverse insults and pathological states cause degeneration of RGC, leading to irreversible blindness or impaired vision. RGCs are the measurable endpoints in current research into experimental therapies and diagnosis in multiple ocular pathologies, like glaucoma. RGC subtype classifications are based on morphological, functional, genetical, and immunohistochemical aspects. Although great efforts are being made, there is still no classification accepted by consensus. Moreover, it has been observed that each RGC subtype has a different susceptibility to injury. Characterizing these subtypes together with cell death pathway identification will help to understand the degenerative process in the different injury and pathological models, and therefore prevent it. Here we review the known RGC subtypes, as well as the diagnostic techniques, probes, and biomarkers for programmed and unprogrammed cell death in RGC

    A new DC corrective OPF based on generator and branch outages modelled as fictitious nodal injections

    Get PDF
    This work deals with a new formulation for the direct current corrective optimal power flow. The formulation is based on the outage of generators and/or branches modelled as fictitious injections of active power. By including that fictitious injections in the optimization problem, the injections are adjusted to the post-contingency state as a consequence of the corrective actions carried out to bring the system back to its normal state. So, when the analysis of contingencies is performed, the classical topological analysis and the subsequent analyses are avoided with this approach. This new formulation uses the sensitivity matrix between branch power flows and powers injected in a power system. An important feature of this matrix is to remain constant during the Contingency Analysis performed for the generation-load scenario (base case) of each period of time to be analysed. The approach proposed is illustrated in the IEEE-RTS of 24buses. The results obtained in this distribution network demonstrate that the proposed methodology can assess the impact of contingencies with an acceptable accuracy and a short computation time.Spanish Ministry of Science and Innovation grant ENE2011-27984Spanish Ministry of Science and Innovation grant ENE2010-18867Junta de Andalucía TEP-517

    Role of ON and OFF Visual Pathways in Rod- and Cone-Driven Flicker Responses

    Get PDF
    Purpose: To evaluate the effects of various retinal neurotransmitters on temporal resolution, particularly, on the Critical Flicker Fusion Frequency (CFF), which has been previously applied in ophthalmic pathophysiologic research. Methods: A binocular physiologic electroretinogram was performed on adult mice. Animals in the control group were injected in the right eye with 1 & mu;L of phosphate-buffered saline (PBS). Animals in the experimental group were injected in the left eye with 1 & mu;L of PBS and in the right eye with 1 & mu;L of PBS to which different molecules were added: 2-amino-4-phosphonobutyric hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES). Initially, rod response was recorded and later the cone response. Results: APB suppressed the rod-driven, but not the cone-driven flicker response. The other agents severely affected the lower flickering frequency response amplitude, in particular, at 3 Hz. The threshold of CFF was lowered from 50 Hz to 40 Hz after applying APB, Glycine, and HEPES. GABA remarkably enhanced rod-driven and cone-driven flicker response at 3 Hz, whereas Glutamate and GABA/Glutamate only did in rod-driven flicker response. Conclusions: Both ON and OFF visual pathways were implied in cone-driven response, but only the ON visual pathway appears to play a relevant role in rod-driven flicker response. Flicker response seems to be enhanced by horizontal cells both in roddriven and cone-driven response. In addition, due to the greater sensitivity of the flicker at low frequencies, it is suggested that pathophysiological studies should be carried out at said frequencies

    Experiencia piloto ECTS en la titulación de Psicología. Asignatura: Psicología de la Educación

    Get PDF
    La experiencia que presentamos es la adaptación de la asignatura Psicología de la Educación al crédito ECTS. Psicología de la educación es una asignatura troncal que se imparte anualmente en tercero de Psicología, con una carga docente de 10,5 créditos. La Psicología de la Educación estudia los cambios de la conducta de los sujetos como consecuencia de los procesos de enseñanza-aprendizaje. Nuestro objetivo fundamental es el estudio de las variables psicológicas con mayor incidencia en contextos educativos formales. La metodología utilizada desde la implantación del crédito ECTS incluye, clases magistrales y prácticas, actividades autoformativas, trabajos en grupo y tutorías que tienen la finalidad de guiar el estudio y trabajo autónomo del alumno. Al comparar los resultados de un curso académico tradicional con el curso de comienzo de la experiencia piloto, hemos observado un descenso en el número de alumnos que suspenden y un incremento de alumnos que obtienen mejores notas. Esto puede deberse al hecho de que el alumno ECTS no se limita a examinarse de la materia en dos momentos del proceso de aprendizaje, sino que con esta metodología el grado de implicación del alumno es durante todo el curso y su grado de implicación determina el éxito de su rendimiento académico

    Sensitivity-based external equivalent for reliability assessment of subtransmission & distribution systems

    Get PDF
    It is well known that topology changes in a power system strongly influences the results of reliability assessment studies. Besides, it is obvious that the topology of an external system also affect the reliability of the internal system through changes on the power flows within the rest of the system, and hence, through changes on the tie lines. In order to properly model the interconnection between the internal network and the rest of the system, an adaptive external equivalent model, obtained from the sensitivity matrix between tie-linepower flows and injectedpowers, is proposed for reliability assessment studies. The proposed technique has been applied to the IEEERTS, and test results show that the proposed methodology is suitable both for planning studies and for 24-hour-ahead reliability assessment studies.Spanish Ministry of Science and Innovation ENE2010-18867Spanish Ministry of Science and Innovation ENE 2007-63306Spanish Ministry of Science and Innovation ENE 2007-66072Ministry of Foreign Affairs and Cooperation A/030124/10Junta de Andalucía TEP-517

    A Hybrid Procedure Including Subtransmission Systems and Substations for Reliability Assessment

    Get PDF
    A new procedure focused on reliability analysis of subtransmission systems supported by the state enumeration technique is presented. This new methodology is conducted in three stages. First, a classical state enumeration reliability assessment is performed for the branch-node model of a subtransmission system, assuming that substations are perfectly reliable. Second, a detailed model of the subtransmission system is considered and the reliability of each substation is assessed by considering them in a “one-by-one” process, supposing perfect operation for the branch-node model. Finally, the reliability indices calculated in the first and second stages are analytically combined to obtain the reliability indices for the subtransmission system (system reliability indices) and for the load nodes of the distribution system (load-node reliability indices). Test results show that the proposed methodology is suitable for both planning studies and 24 hours-ahead security assessment.Spanish Ministry of Science and Innovation grant ENE2010-18867Ministry of Foreign Affairs and Cooperation grant A/030124/10Junta de Andalucía TEP-517

    A new technique for short-term reliability assessment of transmission and distribution networks

    Get PDF
    This paper proposes a new methodology for shortterm (24 hours) reliability assessment of transmission and distribution networks, including detailed substations models. Substations are first considered as single electrical nodes to evaluate the reliability of delivery nodes. If nodes (substations) with a high LOLP (Loss of Load Probability) are identified in this preliminary analysis, the critical substations are modeled in detail to obtain the corresponding reliability indices with a higher accuracy, especially the indices corresponding to delivery points (feeders). The proposed methodology includes a topological analysis module similar to the topological processor used in State Estimation, a DC Load Flow, a DC-OPF module to compute remedial actions, and a reliability evaluation module based on state enumeration. The proposed approach is flexible and easy to implement, and special efforts have been made to reduce the computational requirements and to present the results in a way appropriate to both operators and planning engineers.Ministerio de Ciencia y Tecnología (España) ENE 2004-0334

    Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration

    Get PDF
    Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss.This work was supported by project grants from Spanish Ministerio de Economía y Competitividad-FEDER (http://www.mineco.gob.es) #BFU2012‐36845, Instituto de Salud Carlos III RETICS (http://www.oftared.com) #RD12/0034/0010 and Organización Nacional de Ciegos Españoles (http://www.once.es) to NC; Ministerio de Ciencia e Innovación #JCI‐2009‐05224 to VGV; Universidad de Alicante (http://www.ua.es) #2010-48536273 to GE; Instituto de Salud Carlos III (http://www.isciii.es) #PI13/02098 and RETICS #RD12/0034/0006 to PdV; and FUNDALUCE

    A GSK-3b modulator delays photoreceptor cell death and preserves visual function in the rd10 mouse model of retinitis pigmentosa

    Get PDF
    1 p.Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies that lead to blindness. Photoreceptor cell death, reactive gliosis and retinal inammation are common features in animal models of the disease. The enzyme Glycogen Synthase Kinase-3 Beta (GSK-3b) is involved in inammatory processes associated to diverse neurodegenerative pathologies. The aim of our study is to test in the rd10 mouse whether the GSK-3b inhibitor VP3.15 (a small heterocyclic molecule) is a potential therapeutic treatment for RP.SAF2013-41059-RPeer reviewe

    Consistencia en los estilos de madres y padres y estrés manifestado en adolescentes

    Get PDF
    Este estudio tenía por objetivo examinar si la atribución individual y conjunta del estilo de socialización familiar se relacionaba con las manifestaciones emocionales, fisiológicas y conductuales asociadas al estrés. Ochocientos cincuenta y siete estudiantes de educación secundaria obligatoria, con edades com prendidas entre los 12 y los 16 años, participaron en este estudio. Para identificar los diferentes estilos educativos parentales se realizaron dos análisis de clusters por separado (madres y padres) empleando las puntuaciones otorgadas en diferentes dimensiones (afecto, disciplina inductiva, disciplina rígida y disciplina negligente). Los resultados sugieren que la atribución de un estilo de socialización familiar democrático se relaciona con menores índices de manifestaciones emocionales, fisiológicas y conductuales vinculadas al estrés. Asimismo, la presencia de un padre democrático en la familia parece asociada a la reducción de manifestaciones de estrés cuando se compara con la combinación de cualquier otro patrón incongruente e incluso congruente distinto al democrático. Finalmente, los chicos afirmaron exhibir en mayor grado que las chicas manifestaciones conductuales asociadas al estrés.This study was conducted with the goal of evaluating whether individual and joined attributions of parenting styles (authoritative, permissive, affective-authoritarian and neglectful) was related to emotional, physiological and behavioral manifestations of stress. Eight hundred and fifty seven high school students of compulsory secondary education ranging 12 and 16 years old participated in the study. To identify parenting styles, two separate cluster analyses were conducted on the maternal and paternal parenting variables (caring, inductive discipline, severe discipline and indulgent discipline). Results suggested that authoritative parenting style was linked to lower levels of physiological, emotional and behavioral manifestations of stress. Moreover, the presence of an authoritative parent is linked to stress reduction when compared with any other congruent or incongruent parenting style different from the authoritative one. Finally, boys showed behavioral manifestations of stress in a higher degree than girls
    corecore