15,814 research outputs found

    Bayesian networks for disease diagnosis: What are they, who has used them and how?

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    A Bayesian network (BN) is a probabilistic graph based on Bayes' theorem, used to show dependencies or cause-and-effect relationships between variables. They are widely applied in diagnostic processes since they allow the incorporation of medical knowledge to the model while expressing uncertainty in terms of probability. This systematic review presents the state of the art in the applications of BNs in medicine in general and in the diagnosis and prognosis of diseases in particular. Indexed articles from the last 40 years were included. The studies generally used the typical measures of diagnostic and prognostic accuracy: sensitivity, specificity, accuracy, precision, and the area under the ROC curve. Overall, we found that disease diagnosis and prognosis based on BNs can be successfully used to model complex medical problems that require reasoning under conditions of uncertainty.Comment: 22 pages, 5 figures, 1 table, Student PhD first pape

    Circadian variations in aortic stiffness, sympathetic vasoconstriction, and post-ischemic vasodilation in adults with and without type 2 diabetes.

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    The current literature reveals a lack of information on the circadian variations of some important cardiovascular risk factors related to the work of the heart or the capacity to provide blood and oxygen to various tissues. These factors include aortic stiffness, peripheral vasoconstrictor responsiveness, and post-ischemic vasodilation capacity. Furthermore, it is not clear whether the impact of an external stressor capable of activating the sympathetic nervous system could have greater repercussions on the cardiovascular system in the morning than in the evening. Given the higher incidence of acute cardiovascular events in the morning than in the evening, the studies undertaken in this thesis aim to investigate the circadian variations of these factors that are linked to cardiovascular risk, both at rest and during acute activation of the sympathetic nervous system. Type 2 diabetes (T2DM) is a condition that induces deleterious changes in cardiovascular function, impacting cardiovascular mortality and morbidity. Thus, the impact of diabetes will be evaluated. As a secondary purpose, considering the sex differences in the incidence and prognosis of cardiovascular disease, the effect of sex will be evaluated. Aortic stiffness proved not to be increased in the morning compared to the evening at specific times when the cardiovascular risk is significantly different, both at rest and during sympathetic activation. However, while healthy older women show similar aortic stiffness values compared to their male counterparts during acute stress, older women with T2DM reported greater aortic stiffness compared to men with T2DM. The post-ischemic forearm vasodilation is blunted in the morning compared to the evening in healthy elderly and such an attenuated vasodilation capacity impairs blood flow supply towards the ischemic area. The presence of T2DM does not affect vasodilation capacity and reactive hyperemia, but induces circadian variations in arterial pressure. The peripheral vasoconstriction triggered by a standardized sympathetic stressor is similar between morning and evening, regardless of the presence of T2DM and reduced baseline vascular conductance values in the morning. However, the peripheral vasoconstriction responsiveness is blunted in individuals with T2DM than in healthy ones as sympathetic activation induces vasodilation on the contralateral forearm in individuals with T2DM and vasoconstriction in healthy age-matched subjects. This finding highlights a neurovascular response to an external stressor altered by T2DM. Taken together, our findings suggest that the baseline state of constriction of the peripheral vascular tissue is greater in the morning than in the evening, but this fact is not due to greater sympathetic vasoconstriction responsiveness in the morning. Higher morning vasoconstriction at baseline however affects the capacity of a vascular tissue to dilate and, in turn, to supply blood to an ischemic tissue. Similar sympathetic vasoconstriction responsiveness between morning and evening is a likely factor explaining similar or lower values of central artery stiffness in the morning than in the evening, not only at rest but also during sympathetic excitation. Paradoxically, adults with T2DM report an increase in sympathetic-mediated dilatation capacity on the vascular tissue, which might be a defense mechanism that allows to reduce the central pressor response during sympathetic excitation

    Small newborns in post-conflict Northern Uganda: Burden and interventions for improved outcomes

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    Introduction: A small newborn can be the result of either a low birthweight (LBW), or a preterm birth (PB), or both. LBW can be due to either a preterm appropriate-for gestational-age (preterm-AGA), or a term small-for-gestational age (term-SGA) or intrauterine growth restriction (IUGR). An IUGR is a limited in-utero foetal growth rates or foetal weight < 10th percentile. Small newborns have an increased risk of dying, particularly in low-resource settings. We set out to assess the burden, the modifiable risk factors and health outcomes of small newborns in the post-conflict Northern Ugandan district of Lira. In addition, we studied the use of video-debriefing when training health staff in Helping Babies Breathe. Subjects and methods: In 2018-19, we conducted a community-based cohort study on 1556 mother-infant dyads, nested within a cluster randomized trial. In our cohort study, we estimated the incidence and risk factors for LBW and PB and the association of LBW with severe outcomes. We explored the prevalence of and factors associated with neonatal hypoglycaemia, as well as any association between neonatal death and hypoglycaemia. In addition, we conducted a cluster randomized trial to compare Helping Babies Breathe (HBB) training in combination with video debriefing to the traditional HBB training alone on the attainment and retention of health worker neonatal resuscitation competency. Results: The incidence of LBW and PB in our cohort was lower than the global estimates, 7.3% and 5.0%, respectively. Intermittent preventive treatment for malaria was associated with a reduced risk of LBW. HIV infection was associated with an increased risk of both LBW and PB, while maternal formal education (schooling) of ≥7 years was associated with a reduced risk of LBW and PB. The proportions of neonatal deaths were many-folds higher among LBW infants compared to their non-LBW counterparts. The proportion of neonatal deaths among LBW was 103/1000 live births compared to 5/1000 among the non-LBW. The prevalence of neonatal hypoglycaemia in our cohort was 2.5%. LBW and PB each independently were associated with an increased risk of neonatal hypoglycaemia. Neonatal hypoglycaemia was associated with an increased risk of hospitalisation and severe outcomes. We demonstrated that neonatal resuscitation training with video debriefing, improved competence attainment and retention among health workers, compared to traditional HBB training alone. Conclusion: In northern Uganda, small infants still have a many-fold higher risk of dying compared to normal infants. In addition, small infants are also at more risk of neonatal hypoglycaemia compared to normal infants. Efforts are needed to secure essential newborn care, should we reach the target of Sustainable Development Goal number 3.2 of reducing infant mortality to less than 12/1000 live births by 2030

    Quantum dots based superluminescent diodes and photonic crystal surface emitting lasers

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    This thesis reports the design, fabrication, and electrical and optical characterisations of GaAs-based quantum dot (QD) photonic devices, specifically focusing on superluminescent diodes (SLDs) and photonic crystal surface-emitting lasers (PCSELs). The integration of QD active regions in these devices is advantageous due to their characteristics such as temperature insensitivity, feedback insensitivity, and ability to utilise the ground state (GS) and excited state (ES) of the dots. In an initial study concerning the fabrication of QD-SLDs, the influence of ridge waveguide etch depth on the electrical and optical properties of the devices are investigated. It is shown that the output power and modal gain from shallow etched ridge waveguide is higher than those of deep etched waveguides. Subsequently, the thermal performance of the devices is analysed. With increased temperature over 170 ºC, the spectral bandwidth is dramatically increased by thermally excited carrier transition in excited states of the dots. Following this, an investigation of a high dot density hybrid quantum well/ quantum dot (QW/QD) active structure for broadband, high-modal gain SLDs is presented. The influence of the number of QD layers on the modal gain of hybrid QW/QD structures is analysed. It is shown that higher number of dot layer provides higher modal gain value, however, there is lack of emission from QW due to the requirement of large number of carriers to saturate the QD. Additionally, a comparison is made between “unchirped QD” and “ chirped QD” of hybrid QW/QD structure in terms of modal gain and spectral bandwidth. It is showed that “chirped” of the QD can improve the “flatness” of the spectral bandwidth. Lastly, the use of self-assembled InAs QD as the active material in epitaxially regrown GaAs-based PCSELs is explored for the first time. Initially, it is shown that both GS and ES lasing can be achieved for QD-PCSELs by changing the grating period of the photonic crystal (PC). The careful design of these grating periods allows lasing from neighbouring devices at GS ( ~1230 nm) and ES (~1140 nm), 90 nm apart in wavelength. Following this, the effect of device area, PC etch depth, PC atom shape (circle or triangle or orientation) on lasing performance is presented. It is shown that lower threshold current density and higher slope efficiencies is achieved with increasing the device size. The deeper PC height device has higher output power due to more suitable height and minimal distance to active region. The triangular atom shape has slightly higher slope efficiency compared to triangular atom shape which is attributed to breaking in-plane symmetry and increase out-of-plane emission

    Guía metodológica basada en el uso del podcast educativo como recurso didáctico para la enseñanza y aprendizaje de contenidos curriculares en el área de lengua y literatura para séptimo de básica

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    La presente guía metodológica integra el podcast educativo como recurso didáctico para el aprendizaje de contenidos curriculares de Lengua y Literatura en séptimo de básica. La creación de la guía nació de la observación y aplicación de encuestas en centros educativos del norte y sur de la ciudad de Quito, buscando hacer frente a la desigualdad en el contexto escolar. Con la información obtenida se construyó la propuesta en mención, que comprende dos secciones: una abarca conceptos teóricos y otra presenta las secuencias metodológicas integrando el recurso de autoría inédita y anexos. La guía para el uso del podcast educativo está elaborada bajo los principios del constructivismo; considera los bloques curriculares del área en el subnivel medio y categorías conceptuales como estrategias metodológicas y recursos didácticos. Se concluye que las secuencias de aprendizaje cumplen con los objetivos planteados en el proceso de creación y su aplicación. La recomendación principal es que el personal docente debe desarrollar una competencia digital para el sistema educativo del siglo XXI.This methodological guide integrates the educational podcast as a didactic resource for the learning of curricular contents of Language and Literature in seventh grade. The creation of the guide was born from the observation and application of surveys in schools in the north and south of the city of Quito, seeking to address inequality in the school context. With the information obtained, the proposal in question was built, comprising two sections: one covers theoretical concepts and the other presents the methodological sequences integrating the resource of unpublished authorship and annexes. The guide for the use of the educational podcast is elaborated under the principles of constructivism; it considers the curricular blocks of the area in the intermediate sub-level and conceptual categories as methodological strategies and didactic resources. It is concluded that the learning sequences meet the objectives set out in the creation process and their application. The main recommendation is that teachers should develop a digital competence for the educational system of the 21st centur

    Francisco Laxalte, recomponiendo retazos desde un lugar. Problematizar una experiencia de exilio interior en la frontera uruguaya

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    Francisco, “el Cura” reside en Chuy, localidad fronteriza de Uruguay con Brasil, uno de los confines de un país pequeño. Vive y milita en un lugar que aún le cuesta definir como “su lugar”. Llegó ahí por mandato de las fuerzas represivas de una dictadura cívico militar. Fue detenido, torturado y recorrió varias cárceles políticas hasta que le dieron a “elegir” a su salida: irse al exterior o a la frontera. Es un relato multisituado tanto, desde mi relación vital con el espacio y el tema, como de quien me ha compartido sus recuerdos; cómo se piensa, se representa y se vive el territorio desde una situación de movilidad forzada. Problematizo diferentes dimensiones: conceptual –exilio-, historiográfica –relato histórico- y espacial -la frontera-. Para ello, realicé entrevistas en profundidad y conversaciones informales entre 2020 y 2022. El análisis se hace desde una lectura crítica del concepto de exilio interior, el concepto de lugar como pertenencia y lo político, como sentido de vida. Este texto nos habla de mecanismos de exclusión, control y de cómo los representantes del aparato represivo de la dictadura cívico militar uruguaya actuaron frente a quienes identificaban como un “peligro”

    La aparición de la partida doble en la Iglesiael diario y los mayores de la Catedral de Toledo, 1533-1539

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    The findings of the studies on accounting of the religious organizations in Spain prove the ability that these organizations have had throughout the history in the management and internal control system and the most novel accounting techniques. Such findings stand in contradiction to the opinion that some specialists have about the present economic and financial management in the religious organizations. These authors agree that their accounting systems are primitive and inadequate, the internal control is poor and the institutions do not have expertise in financial management. In addition, they affirm that these facts are conditioned by the spiritual or sacred dimension of these organizations. Through an approach close to the research of the history of these religious organizations in Spain, this paper intends to study an entity that was considered the richest see of Christendom after Rome in the 16th century. We refer to the Cathedral of Toledo. This Cathedral had an important level of resources that were originated from the exploitation of an important inheritance (royal donations and private donations) and from the collection of the tithes. Its highest level of financial resources could possibly have been a significant element in the development of sophisticated management and accounting practices in this church. In addition, the role of the clergy (prebendaries) in this process was a key factor. Acting at the cathedral of Toledo, there were men who were capable to manage any economic question. Some clergies were members of the rich families of merchants in the city. Therefore, we will emphasize the importance of these men in the process of development of management and accounting in such organization. More specifically, one of these prebendaries was the author of the first accounting demonstration for double entry in the cathedral of Toledo and the first one that is known, at the present time, in a religious organization on the world. Such demonstration is composed of one journal and three ledgers (1533-1539). The person responsible for it was a collector of incomes in the cathedral, Gutierre Hurtado. Thus, this paper will show some features of all what we know about his life and his job (we have specially considered the period he performed his position). In addition to his role in the organization, we analyze some essential and special features that characterize the accounting method that was used by this administrator. To meet this objective, we have examined the historical documents, which are kept in the archive of the cathedral of Toledo. As mentioned above these documents are a journal (1535-1536) and three ledgers (1533- 1535, 1535-1536 and 1537-1539), as well as plenty of other papers which supply complementary information. This article concludes with some reflections and a summary of the findings of this research. These findings may be taken as a sign of the high level of sophistication that church accounting could have reached in Spain by this time. In addition, they also show how the church did not offer any resistance to innovative accounting and management techniques on account of its sacred condition.Los resultados de las investigaciones sobre la contabilidad de las instituciones eclesiásticas en España vienen mostrando la capacidad que las mismas han tenido a lo largo de la historia en el desarrollo de los procedimientos de gestión y control interno y en las técnicas contables más novedosas. Estos hallazgos contradicen la opinión que algunos especialistas tienen de la actual gestión económica y financiera de las instituciones eclesiásticas. Tales autores coinciden en señalar que su contabilidad es primitiva e inadecuada, el control interno pobre y no cuentan con directivos financieros expertos. Además, sostienen que su retraso podría estar relacionado con su dimensión espiritual. En la línea de las investigaciones desarrolladas sobre estas instituciones eclesiásticas en España, este trabajo se acerca al conocimiento de la que en el siglo XVI fue considerada la sede más rica de la Cristiandad después de Roma. Nos referimos a la catedral de Toledo. Esta institución disfrutaba de un elevado número rentas, procedentes de la explotación de un importante patrimonio (donaciones reales y privadas) y del cobro de los diezmos. Su elevado estatus financiero pudo ser una cuestión significativa para influir en el proceso de desarrollo de su sistema de gestión y en la adopción de prácticas contables novedosas. También el papel de los capitulares en este proceso fue un factor clave en este desarrollo. Dentro de la catedral de Toledo existían hombres con aptitudes para dar solución a cualquier asunto. Algunos capitulares eran miembros de ricas familias de mercaderes de la ciudad. Por tanto, insistiremos en el importante papel de estos hombres en el desarrollo contable y de gestión de esta organización. Mas concretamente, uno de los beneficiados de la Iglesia de Toledo fue la persona responsable de la primera muestra de contabilidad por partida doble en la catedral de Toledo y la primera muestra conocida, hoy por hoy, en el mundo para una entidad eclesiástica. Dicha muestra la componen un diario y tres mayores (1533-1539). La persona responsable fue un receptor de rentas en la Catedral, el racionero Gutierre Hurtado. Así, en este trabajo se muestran algunos fragmentos de lo que conocemos sobre su vida y cometido (especialmente hemos considerado el período en el que desempeñó su cargo). Además de su papel en la organización, analizaremos algunos aspectos generales y especiales que caracterizan el método contable usado por el mismo. Para ello, examinaremos los documentos históricos que se conservan en el Archivo Capitular de Toledo (A.C.T.). Estos documentos son un diario (1535-1536), algunos mayores (1533-15351, 1535-1536 y 1537-1539) y otros expedientes que contienen información complementaria al respecto. Este artículo concluye con algunas reflexiones y un resumen de los resultados. Estos resultados podrían tomarse como indicativo de que la contabilidad pudo ser altamente sofisticada en la Iglesia. Además, el estudio prueba que esta institución no ofreció resistencia a la contabilidad y a las avanzadas técnicas de gestión a causa de su condición sagrada

    Magnetic braking with MESA evolutionary models in the single star and LMXB regimes

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    Magnetic braking has a prominent role in driving the evolution of close low mass binary systems and heavily influences the rotation rates of low mass F- and later type stars with convective envelopes. Several possible prescriptions that describe magnetic braking in the context of 1D stellar evolution models currently exist. We test four magnetic braking prescriptions against both low mass X-ray binary orbital periods from the Milky Way and single star rotation periods observed in open clusters. We find that data favors a magnetic braking prescription that follows a rapid transition from fast to slow rotation rates, exhibits saturated (inefficient) magnetic braking below a critical Rossby number, and that is sufficiently strong to reproduce ultra compact X-ray binary systems. Of the four prescriptions tested, these conditions are satisfied by a braking prescription that incorporates the effect of high order magnetic field topology on angular momentum loss. None of the braking prescriptions tested are able to replicate the stalled spin down observed in open cluster stars aged 700 - 1000 Myr or so, with masses \lesssim 0.8 M\rm M_{\odot}.Comment: 20 pages, 5 figure

    Constraints on Incremental Assembly of Upper Crustal Igneous Intrusions, Mount Ellen, Henry Mountains, Utah

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    Magma systems within the shallow crust drive volcanic processes at the surface. Studying active magma systems directly poses significant difficulty but details of ancient magma systems can provide insight to modern systems. The ancient intrusions now exposed in the Henry Mountains of southern Utah provide an excellent opportunity to study the emplacement of igneous intrusions within the shallow crust. The five main intrusive centers of the Henry Mountains are Oligocene in age and preserve different stages in the development of an igneous system within the shallow crust. Recent studies worldwide have demonstrated that most substantial (> 0.5 km3) igneous intrusions in the shallow crust are incrementally assembled from multiple magma pulses. In the Henry Mountains, smaller component intrusions (< 0.5 km3) clearly demonstrate incremental assembly but an evaluation of incremental assembly for an entire intrusive center has yet to be performed. The Mount Ellen intrusive complex is the largest intrusive center (~ 100 km3, 15 – 20 km diameter) in the Henry Mountains. This thesis research provides constraints on the construction history and emplacement of Mount Ellen using a combination of multiple techniques, including fieldwork, whole-rock major and trace element geochemistry, anisotropy of magnetic susceptibility, and crystal size distribution analysis. Field work and anisotropy of magnetic susceptibility data suggest that Mount Ellen is a laccolith that in cross section is built a network of stacked igneous sheets. In map-view, the laccolith has an elliptical shape built from numerous igneous lobes radiating away from the central portion of the intrusion. Field observations suggest most lobes are texturally homogenous and likely emplaced from a single magma batch. Samples collected throughout Mount Ellen were divided into five groups based on a qualitative evaluation of texture. Possible distinctions between these textural groups were then tested using several different techniques. Geochemistry, anisotropy of magnetic susceptibility, and phenocryst crystal size distribution data are individually not sufficient to distinguish all five textural groups. However, limited datasets for two textures can be consistently distinguished using these techniques. These new results can be integrated with existing constraints to create a comprehensive model for the construction history of Mount Ellen. The intrusive center was constructed in approximately 1 million years at a time-averaged magma injection rate of 0.0004 km3 y-1. The laccolith geometry was built from a radiating network of stacked igneous sheets. The sheets are lobate in map-view (longer than they are wide) and were fed radially outward from a central feeder zone. These component intrusions were emplaced by a minimum of 5 texturally distinct magma pulses, with periods of little or no magmatism between sequential pulses
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