13 research outputs found

    Accretion onto Neutron Stars: Hydrodynamics and Nucleosynthesis

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    In the middle of the 70s, some authors suggested that accretion of hydrogen and helium rich material by a neutron star in a binary system, where the companion star would have low mass, could explain thermonuclear bursts observed by the first satellites launched to the space in order to analyze the Xray band of the electromagnetic spectrum. This phenomenon, known as type I X-ray bursts (XRB), is a thermonuclear runaway produced by the themonuclear fusion of the accreted material in degenerated conditions. This kind of explosion from stellar source is the most frequent in our galaxy (and the third, after supernovae and classical novae, in terms of total output energy), because his short recurrence period. Due to the extreme gravitational field of a neutron star it is known that produced nucleosynthesis is not ejected to the interstellar medium but forming part of the neutron star crust.In this work we have tried, first, to study the effects of nuclear uncertainties, related to nuclear reaction rates, in the nucleosynthesis produced during a X-ray burst, and second, to simulate physical properties and associated nucleosynthesis to this kind of events, through hydrodynamical models.In order to analyze the impact of uncertainties of the nuclear reaction rates in the nucleosynthesis, and due to the prohibitive calculation time with an hydrodinamical code, we have used a post-processing code which we have coupled, for a given set of 10 temperatures and densities profiles, an extensive nuclear reactions network formed by 606 isotopes and 3551 nuclear reactions, whose reaction rates have been modified using to alternative methods. In the first one, every rate has been individually modified, multiplying it by 0.1 and 10, calculating the final nucleosynthesis. This way, it is possible to evaluate the impact in final nucleosynthesis individual variations in the nuclear reaction rates. Also we have analyzed the effects in final nucleosynthesis by modifying the energy associated to each reaction (Q-value). In the second method, nuclear reaction rates have been modified simultaneously, multiplying each one by a random factor which follow a log-normal distribution with a probability of 95.5% of being in the interval [0.1,10]. In order to analyzed this method from an statistically point of view, the nucelosynthesis has been calculated up to 10,000 times, with a Monte Carlo code specifically built to this Thesis, for different set of random numbers. Obtained results with both methods are coincidents and show that for a network formed by 3,500 reactions approximately, only about 60 reactions have an impact in final yields greater than a factor of 2.Finally, we have used an hydrodynamical code, one-dimensional (spherically symmetric), Lagrangian and multi-shell, to which we have coupled a nuclear reactions network formed by 324 isotopes and 1392 reactions with the aim of reproduce physical parameters and nucleosynthesis produced during X-ray bursts. To do that, we have applied this code to different models, analyzing the effect of spatial resolution in the accreted shell, the metallicity of the transferred material as well as the mass of the neutron star, in the final result. For each model, we have simulated different bursts, with energies, luminosities and recurrence times coincidents with observations and, together with the nucleosynthesis, similar to the results obtained by other authors.A mediados de los años 70, varios autores sugirieron que la acreción de material rico en hidrógeno y helio por parte de una estrella de neutrones, integrante de un sistema binario donde la masa de la estrella compañera fuese pequeña, podría explicar las erupciones termonucleares observadas por los primeros satélites lanzados al espacio para analizar la banda X del espectro electromagnético. Dicho fenómeno, conocido como erupciones de rayos X de tipo I (en inglés, type I X-ray bursts, XRB), consiste en el alud termonuclear producido por la fusión termonuclear del material acretado, en condiciones degeneradas. Este tipo de explosión termonuclear de origen estelar es el más frecuente en nuestra galaxia (y el tercero, tras las supernovas y las novas clásicas, en términos de energía total liberada), debido a su corto periodo de recurrencia. Como consecuencia del extremo campo gravitatorio de una estrella de neutrones, se cree que la nucleosíntesis producida durante este tipo de eventos no es expulsada al medio interestelar, pasando a formar parte de la corteza de la estrella.En este trabajo hemos intentado, por un lado, estudiar los efectos de las incertidumbres de origen nuclear, asociadas a los ritmos de las reacciones nucleares, en la nucleosíntesis producida durante un X-ray burst; y por otro lado, simular las propiedades físicas y la nucleosíntesis asociada a este tipo de eventos, mediante modelos hidrodinámicos.Para estudiar el impacto de las incertidumbres de los ritmos de las reacciones nucleares en la nucleosíntesis, y debido a que el tiempo de cálculo con un código hidrodinámico resultaría prohibitivo, hemos utilizado un código de post-procesado al que se ha acoplado, para un conjunto determinado de 10 perfiles de temperatura y densidad, una extensa red de reacciones nucleares, formada por 606 isótopos y 3551 reacciones nucleares, cuyos ritmos de reacción han sido modificados utilizando dos métodos alternativos. En el primero, cada ritmo ha sido modificado individualmente, multiplicándolo por 0.1 y 10, calculándose la nucleosíntesis final. De esta manera, puede evaluarse el impacto que tienen en las abundancias finales las variaciones individuales de los ritmos de las reacciones nucleares.Así mismo, también se ha analizado el efecto que produce en las abundancias finales el hecho de modificar la energía asociada a cada reacción (Q-value). En el segundo método, los ritmos nucleares se han modificado simultáneamente, multiplicando cada uno de ellos por un factor aleatorio según una distribución log-normal, y cuya probabilidad de encontrarse en el intervalo [0.1,10] es del 95,5%. Para poder hacer una estimación estadística de este último método, se ha calculado la nucleosíntesis hasta 10.000 veces, con un código Monte Carlo específicamente construido para esta Tesis, para diferentes conjuntos de números aleatorios. Los resultados obtenidos con ambos métodos son coincidentes y demuestran que, para una red formada por unas 3500 reacciones nucleares, sólo unas 60 reacciones tienen un impacto en las abundancias finales mayor que un factor 2.Por último, hemos utilizado un código hidrodinámico, unidimensional (en simetría esférica), Lagrangiano y multicapa, al que se ha acoplado una red de reacciones nucleares formada por 324 isótopos y 1392 reacciones nucleares, con el objetivo de reproducir los parámetros físicos y la nucleosíntesis producida en los X-ray bursts. Para ello, hemos aplicado este código a diferentes modelos, analizando el efecto de la resolución espacial de la capa acretada, la metalicidad del material transferido, así como la masa de la estrella de neutrones, en el resultado final. Para cada modelo, hemos simulado diferentes erupciones, con energías, luminosidades, y periodos de recurrencia, coincidentes con las observaciones y, junto con la nucleosíntesis, similares a los resultados obtenidos por otros autores

    Effectiveness of eHealth-Based Psychological Interventions for Depression Treatment in Patients With Type 1 or Type 2 Diabetes Mellitus: A Systematic Review

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    Background: This systematic review aims to update the available information on the efficacy of psychological interventions delivered through ICTs to improve depressive symptomatology in patients with diabetes. Methods: A systematic review of the literature was performed following the PRISMA guidelines and using MEDLINE, Embase, PubMed, Web of Science, PsycINFO, Scopus, and Cochrane Library databases to search for randomized clinical trials of eHealth treatments for patients with diabetes and comorbid depression from 1995 through 2020. In addition, studies related to follow-up appointments were identified. I Results: The initial search identified 427 relevant scientific publications. After removing duplicates and ineligible citations, a total of 201 articles were analyzed in full text. Ten articles met the criteria of this review and were included, obtaining very good scientific quality after evaluation with the PEDro scale. The main results show that the eHealth psychological intervention for depression in patients with diabetes showed beneficial effects both at the end of treatment and in the short (3 months) and long term (6 and 12 months) for the improvement of depressive symptomatology. Conclusions: ICT-based psychological interventions for the treatment of depression in people with diabetes appear to be effective in reducing depressive symptomatology but do not appear to provide significant results with regard to glycemic control.The translation of this article was carried out with funding from the Puente Project (B.4) of the University of Malaga, entitled Efficacy and Cost-Effectiveness of a Web Application to treat Depressive symptoms in adults with type 1 Diabetes: A controlled clinical trial (20-02-2021 /28-02-2022

    The andalusian “multiplex families with bipolar disorder “: a revaluation of the cohort study (1997-2013).

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    Objectives. Bipolar disorder (BD) is highly heritable, and gene identification will elucidate biological factors and gene-environment interactions. Multiplex families represent a promising resource for identifying rare variants and polygenic effects. However, such families are difficult to recruit. In 1997, >100 multiplex Andalusian BD pedigrees - the largest of which contains >20 affected members- were recruited within an Andalusian-German collaboration study. Since then, the Andalusian psychiatric network and biobank facilities have been expanded in order to facilitate psychiatric research. Therefore in 2013, the Andalusian-German collaborators initiated a follow-up study of this cohort in order to identify new genetic and environmental factors for BD aetiology and clinical course. Methods. In 1997, BD patients at Andalusian psychiatric hospitals who reported a family history of BD were asked to inform their families about the study. All consenting family members (N= 937; BPI/II=265; Recurrent Mayor Depression=149) were assessed using a structured psychiatric interview for life-time best estimate psychiatric diagnosis (SADS) and the family history method, and blood was obtained for DNA genetic analysis. Follow-up involves reassessment of diagnosis, neuropsychological testing (CANTAB), and the collection of biomaterials (RNA, Plasma, IPS, hair cortisol, etc.). Written informed consent is obtained for all study procedures and analyses. Results. For the first three families, follow-up assessments and biomaterial-processing have been completed. Follow-up of the remaining families is ongoing. Conclusion. This cohort represents a unique resource for the investigation of BD aetiology and clinical course, and will be available to international researchers from other sciences.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Manual de simulación clínica en especialidades médicas

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    Manual sobre técnicas y modos de simulación clínica en diversas especialidades médicas.La enseñanza y formación en medicina necesita el uso de la simulación. Existen evidencias de su uso desde hace cientos de años, pero, en los últimos años se ha incrementado y diseminado. La simulación clínica está validada científicamente en múltiples contextos médicos y de otras áreas profesionales de la salud. Y es considerada de gran importancia como proceso de entrenamiento y de mejora de las competencias y adquisición de habilidades médicas en campos que incluye desde la historia clínica, comunicación con el paciente, exploración, diagnóstico terapéutica médica-farmacológica y quirúrgica y seguridad al tratar al paciente. Hoy en día, para muchas técnicas y situaciones clínicas es inaceptable llegar junto a los pacientes sin un dominio adquirido en simulación. La simulación puede ocurrir sin el uso de recursos adicionales, solo las personas, o utilizando pocos o muchos recursos de baja hasta alta tecnología y se puede adaptar a los recursos disponibles, abarcando todas las áreas de conocimiento, y dentro de ellas competencias técnicas o actitudes, solas o en conjunto. El uso racional y basado en evidencia de la simulación es de la mayor importancia por la necesidad de una mayor efectividad y eficiencia en la transformación de los profesionales de la salud para que puedan mejorar su capacidad de atender a los pacientes. La simulación es también una buena herramienta de evaluación de competencias y habilidades en Medicina y otras disciplinas de las Ciencias de la Salud Este manual incluye técnicas y modos de simulación clínica en diversas especialidades médicas, útiles, para quien busque un manual práctico y actualizado.Cátedra de Mecenazgo de la Universidad de Málaga. Cátedra de Terapias Avanzadas en Patología Cardiovascular Cátedra de Mecenazgo de la Universidad de Málaga. Cátedra de Investigación Biomédica Quirón Salu

    Resultados Semilleros de Investigación 2009-2010

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    La publicación recoge los doce informes finales de investigación presentados por los estudiantes de ocho Semilleros 1 y cuatro Semilleros 2, correspondientes a la convocatoria 2009–2010 y se constituye en el Número 25 de la Serie de Investigaciones en Construcción, si bien este es el primer Número publicado en formato digital que UNIJUS se permite poner a disposición no sólo de la comunidad universitaria, sino también de la sociedad colombiana e internacional, interesada en los temas estudiados por los jóvenes investigadores de la Facultad de Derecho, Ciencias Políticas y Sociales de la Universidad Nacional de Colombia

    Effectiveness of eHealth-Based Psychological Interventions for Depression Treatment in Patients With Type 1 or Type 2 Diabetes Mellitus: A Systematic Review.

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    Comorbidity between diabetes mellitus and depression is highly prevalent. The risk of depression in a person with diabetes is approximately twice that of a person without this disease. Depression has a major impact on patient well-being and control of diabetes. However, despite the availability of effective and specific therapeutic interventions for the treatment of depression in people with diabetes, 50% of patients do not receive psychological treatment due to insufficient and difficult accessibility to psychological therapies in health systems. The use of information and communication technologies (ICTs) has therefore been proposed as a useful tool for the delivery of psychological interventions, but it continues to be a field in which scientific evidence is recent and controversial. This systematic review aims to update the available information on the efficacy of psychological interventions delivered through ICTs to improve depressive symptomatology in patients with diabetes. A systematic review of the literature was performed following the PRISMA guidelines and using MEDLINE, Embase, PubMed, Web of Science, PsycINFO, Scopus, and Cochrane Library databases to search for randomized clinical trials of eHealth treatments for patients with diabetes and comorbid depression from 1995 through 2020. In addition, studies related to follow-up appointments were identified. Inclusion criteria were as follows: (a) randomized clinical trials (RCTs); (b) patients with type 1 and type 2 diabetes; (c) adult population over 18 years of age; (d) presence of depressive symptomatology assessed with standardized instruments; (e) treatments for depression based on established psychotherapeutic techniques and principles; (f) delivered through eHealth technologies. We did not limit severity of depressive symptomatology, delivery setting or comparison group (treatment as usual or other treatment). Two coauthors independently reviewed the publications identified for inclusion and extracted data from the included studies. A third reviewer was involved to discuss discrepancies found. The PEDro scale was used to assess the quality of the RCTs. No meta-analysis of the results was performed. The protocol used for this review is available in PROSPERO (Reg; CRD42020180405). The initial search identified 427 relevant scientific publications. After removing duplicates and ineligible citations, a total of 201 articles were analyzed in full text. Ten articles met the criteria of this review and were included, obtaining very good scientific quality after evaluation with the PEDro scale. The main results show that the eHealth psychological intervention for depression in patients with diabetes showed beneficial effects both at the end of treatment and in the short (3 months) and long term (6 and 12 months) for the improvement of depressive symptomatology. The methodology used (type of diabetes, eHealth technology used, recruitment context, implementation and follow-up) was very heterogeneous. However, all studies were based on cognitive-behavioral tools and used standardized assessment instruments to evaluate depressive symptomatology or diagnosis of MDD. Glycemic control was assessed by glycosylated hemoglobin, but no benefits were found in improving glycemic control. Only four studies included psychoeducational content on diabetes and depression, but none used tools to improve or enhance adherence to medical prescriptions or diabetes self-care. ICT-based psychological interventions for the treatment of depression in people with diabetes appear to be effective in reducing depressive symptomatology but do not appear to provide significant results with regard to glycemic control. Nonetheless, the scientific evidence reported to date is still very limited and the methodology very diverse. In addition, no studies have implemented these systems in routine clinical practice, and no studies are available on the economic analysis of these interventions. Future research should focus on studying and including new tools to ensure improvements in diabetes outcomes and not only on psychological well-being in order to advance knowledge about these treatments. Economic evaluations should also be undertaken to analyze whether these treatment programs implemented using eHealth technologies are cost-effective
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