搜索结果：African journal of emergency medicine : Revue africaine de la medecine d'urgence

ESPANOL: Una experiencia que parte del uso de un espejo plano colocado horizontalmente a la altura de la nariz del observador, que permite uma nueva dimension a la experiencia de ver imagenes com espejos simples, sirve para discutir lo que aun puede hacerse para que el estudiante gane uma vision mas profunda y conceptual en el aprendizaje de la fisica. El enfasis esta en la idea de independencia mental, que incluye la de que nuevos resultados pueden surgir en el analisis de experimentos que no necesariamente precisan ser hechos con elementos nuevos o de sofisticada realizacion. ENGLISH TRANSLATION: The experience of employing a plane mirror located at the height of the nose of an observer, giving a new dimension to the experiences made with simple mirrors, is used as an example into the discussion of what can be done for the student to reach a deeper and conceptual insight in learning Physics. The main idea lays on the mental independence, which includes that new results can come through the analysis of experiments which not necessarily needs to be made with new elements or through a sophisticated procedure.

Sujets qui sont plus particulierement abordes dans ce cours: 1. Elements de cosmologie, l'Univers homogene Les principes cosmologiques et leurs verifications observationnelles Histoire thermique de l'Univers Inflation, motivations et principe de base 2. Elements de cosmologie, l'Univers inhomogene La croissance des fluctuations Pourquoi un modele avec de la Matiere Noire Froide ? Evidences de l'existence de matiere noire 3. La dynamique gravitationnelle, les theories lineaires L'approximation Newtonnienne avec un seul flot Description Eulerienne ou description Lagrangienne Vers la dynamique non-lineaire: l'effondrement spherique 4. Le regime quasilineaire Effet du couplage de mode: la skewness La hierarchie des correlations en regimes quasi-lineaire Les termes sous-dominants du developpement perturbatif 5. Application aux proprietes statistiques des champs de distorsions gravitationnelles La relation entre convergence locale et densite projetee Variance et skewness de la convergence locale 6. Vers le regime fortement non-lineaire Les solutions auto-similaires et les modeles hierarchiques Distribution de matiere et distribution de lumiere

The identity of the famous place of La Mancha appearing at the Quijote is an unknown with a history almost as long as that of the famous book by Miguel de Cervantes. This work analyzes data obtained from a Geographic Information System and compares the results with those of the previous works. Three different variables with two possible values each are considered: time or space data, 3 or 4 reference points, and the commonly used distances to the place of La Mancha or a set of recently proposed ones. The village in the Campo de Montiel which is closest to be the place of La Mancha happens to be Carrizosa or Villanueva de los Infantes, depending on the configuration, with the latter being the solution for the configuration in which the relative errors are the smallest and the second candidate village is furthest from the first. ----- La identidad del famoso lugar de la Mancha que aparece en El Quijote es una incógnita con una historia casi tan larga como la publicación de la famosa obra de Miguel de Cervantes. Este trabajo analiza datos obtenidos mediante un Sistema de Información Geográfica y compara los resultados con los de los trabajos anteriores. Se consideran tres variables di

Large language models, such as the well-known ChatGPT, have brought about an unexpected revolution in the field of artificial intelligence. On the one hand, they have numerous practical applications and enormous potential still to be explored. On the other hand, they are also the subject of debate from scientific, philosophical, and social perspectives: there are doubts about the exact mechanisms of their functioning and their actual capacity for language comprehension, and their applications raise ethical dilemmas. In this chapter, we describe how this technology has been developed and the fundamentals of its operation, allowing us to better understand its capabilities and limitations and to introduce some of the main debates surrounding its development and use. -- Los grandes modelos de lenguaje, como el conocido ChatGPT, han supuesto una inesperada revolución en el ámbito de la inteligencia artificial. Por un lado, cuentan con multitud de aplicaciones prácticas y un enorme potencial todavía por explorar. Por otro lado, son también objeto de debate, tanto desde el punto de vista científico y filosófico como social: hay dudas sobre los mecanismos exactos de su funcionamiento y su

Currently, the diagnosis of Alzheimer's disease is a complex and error-prone process. Improving this diagnosis could allow earlier detection of the disease and improve the quality of life of patients and their families. For this work, we will use 249 brain images from two modalities: PET and MRI, taken from the ADNI database, and labelled into three classes according to the degree of development of Alzheimer's disease. We propose the development of a convolutional neural network to perform the classification of these images, during which, we will study the appropriate depth of the networks for this problem, the importance of pre-processing medical images, the use of transfer learning and data augmentation techniques as tools to reduce the effects of the problem of having too little data, and the simultaneous use of multiple medical imaging modalities. We also propose the application of an evaluation method that guarantees a good degree of repeatability of the results even when using a small dataset. Following this evaluation method, our best final model, which makes use of transfer learning with COVID-19 data, achieves an accuracy d 68\%. In addition, in an independent test set, th

The main objective of this work is to examine possible effects of using freshman student subjects in software engineering experiments. Particularly in this work we report the effectiveness measured as percentage of observed and observable defects of two software testing techniques: Black-box and white-box. Regarding observed defects, both techniques show an effectiveness around of 4%. With respect of observable defects by test cases, black-box testing is slightly more effective (21%) than white-box testing (16%), although this difference is not significant. We observe a considerable lack of technical skills of subjects for applying both software testing techniques. Due to observed findings, we suggest to employ students with more technical skills for carrying out software engineering experiments. ----- El objetivo de este trabajo se centra en investigar los efectos que conlleva realizar experimentos en ingeniería de software (IS) empleando como sujetos experimentales a estudiantes de pregrado cursando su primer año de estudios de la carrera en ingeniería de software. De manera particular en este trabajo se investiga la efectividad medida en porcentaje de defectos observados y obser

The linguistic diversity across the African continent presents different challenges and opportunities for machine translation. This study explores the effects of data augmentation techniques in improving translation systems in low-resource African languages. We focus on two data augmentation techniques: sentence concatenation with back translation and switch-out, applying them across six African languages. Our experiments show significant improvements in machine translation performance, with a minimum increase of 25\% in BLEU score across all six languages. We provide a comprehensive analysis and highlight the potential of these techniques to improve machine translation systems for low-resource languages, contributing to the development of more robust translation systems for under-resourced languages.

This review presents a brief discussion of the theory of Cold Dark Matter of structure formation in the universe, describing the main processes determining the power spectrum, the non-linear gravitational collapse, the formation of galaxies and the evolution of the intergalactic medium. Recent advances in the observations of high redshift galaxies, and their interpretation in the context of this theory, are then summarized. Este art\'ıculo de revisión presenta una breve exposición de la teor\'ıa de la Materia Invisible Fr\'ıa de la formación de estructura en el universo, describiendo los procesos más importantes que determinan el espectro de potencia, el colapso gravitatorio no lineal, la formación de galaxias y la evolución del medio intergaláctico. Resumimos también los avances recientes en las observaciones de galaxias a alto corrimiento al rojo, y la interpretación en el contexto de esa teor\'ıa.

Con la intencion de realizar una pequena aportacion en la celebracion del ano 2005, proclamado como Ano Internacional de la Fisica, el cuerpo academico de Particulas, Campos y Astrofisica de la Universidad Autonoma de Zacatecas presenta un pequeno esbozo de los trabajos realizados por Einstein en 1905, asi como un conjunto de ensayos sobre electrodinamica clasica, el grupo de Lorentz, neutrinos y relatividad general, todos estos relacionados con los temas de investigacion que realizamos. ----- The Astrophysics, Particles and Fields Unit of the Zacatecas University presents a brief essay of the Einstein historical works (1905) and a set of essays on modern development in the classical electrodynamics, the Lorentz group, neutrinos and the general relativity. The aim is to contribute to the special issue of the UAEM Journal, which is dedicated to the International Year of Physics. The corresponding topics of the article are related to the research work of the authors.

Rankings of scholarly journals based on citation data are often met with skepticism by the scientific community. Part of the skepticism is due to disparity between the common perception of journals' prestige and their ranking based on citation counts. A more serious concern is the inappropriate use of journal rankings to evaluate the scientific influence of authors. This paper focuses on analysis of the table of cross-citations among a selection of Statistics journals. Data are collected from the Web of Science database published by Thomson Reuters. Our results suggest that modelling the exchange of citations between journals is useful to highlight the most prestigious journals, but also that journal citation data are characterized by considerable heterogeneity, which needs to be properly summarized. Inferential conclusions require care in order to avoid potential over-interpretation of insignificant differences between journal ratings. Comparison with published ratings of institutions from the UK's Research Assessment Exercise shows strong correlation at aggregate level between assessed research quality and journal citation `export scores' within the discipline of Statistics.

In this article we review the present knowledge on the elastic properties of membranes of biological origin. Assuming the fluid mosaic hypothesis, we consider the phospholipid bilayer as the structural base of a biological membrane. We expose a model due to Helfrich which can be used to obtain an expression for the membrane elastic energy. The free energy is completely characterized by two local principal curvatures and four parameters that depend on the chemical composition of the membrane and its local environment. In addition we present the theoretical justification of an experimental method (the Micropipette Manipulation technique) that may be used to measure the membrane rigidity. Finally, we describe some physical consequences of these concepts, such as the explanation of the lamellar-sponge phase transition and the emergence of the steric interaction between membranes. ------ Se presenta una revisión del conocimiento actual sobre las propiedades elásticas de las membranas. Bajo la hipótesis del mosaico fluido se considera a una bicapa de fosfolípido como la base estructural de una membrana biológica y se expone un modelo debido a Helfrich a partir del cuál se obtiene una exp

Educative platforms are at the heart of the development of online education. They can not only be reduced to technological aspects. Underlying models impact teaching and learning from the preparing of lessons to the learning sessions. Research related to these platforms are numerous and their stakes are important. For these reasons, we launched a call to a special issue on "Designs and uses of educative platforms" An educative platform is a computer system designed to automate various functions relating to the organization of the course, to the management of their content, to the monitoring of learners and supervision of persons in charge of various formations (Office de la langue française, 2005). So educative platforms are Learning Management Systems (LMS) which are specific to education contexts.

Dyads of journals related by citations can agglomerate into specialties through the mechanism of triadic closure. Using the Journal Citation Reports 2011, 2012, and 2013, we analyze triad formation as indicators of integration (specialty growth) and disintegration (restructuring). The strongest integration is found among the large journals that report on studies in different scientific specialties, such as PLoS ONE, Nature Communications, Nature, and Science. This tendency towards large-scale integration has not yet stabilized. Using the Islands algorithm, we also distinguish 51 local maxima of integration. We zoom into the cited articles that carry the integration for: (i) a new development within high-energy physics and (ii) an emerging interface between the journals Applied Mathematical Modeling and the International Journal of Advanced Manufacturing Technology. In the first case, integration is brought about by a specific communication reaching across specialty boundaries, whereas in the second, the dyad of journals indicates an emerging interface between specialties. These results suggest that integration picks up substantive developments at the specialty level. An advantage o

The scattered starlight which contaminates the spectrum of a reddened star depends on l as 1/lambda^n (n*4), and must be attributed to small particles. Surprisingly these particules, which have a quasi-isotropic phase function, do not participate to the brightness of the nebulae. The importance of the intensity of the scattered light present in the spectrum of reddened stars can be explained only if the scattering is coherent. The intensity of the scattered light is then proportional to the square of the number of particles, and is concentrated within an angle of 10^{-8}" from the star. The scatterers can be small grains, or, atoms or molecules from the gas. Hydrogen satisfies the conditions imposed to the scatterers. -- La lumiere diffusee qui contamine le spectre des etoiles rougies a une dependance en 1/lambda^n (n>=4), caracteristique de particules petites devant la longueur d'onde. Il est surprenant que ces particules, qui doivent diffuser de facon quasi-isotrope, ne contribuent pas a la brillance des nebuleuses. L'importance de la lumiere diffusee par ces petites particules dans le spectre d'une etoile rougie s'explique seulement si la diffusion est coherente. L'intensite

Background: AI-driven prediction algorithms have the potential to enhance emergency medicine by enabling rapid and accurate decision-making regarding patient status and potential deterioration. However, the integration of multimodal data, including raw waveform signals, remains underexplored in clinical decision support. Methods: We present a dataset and benchmarking protocol designed to advance multimodal decision support in emergency care. Our models utilize demographics, biometrics, vital signs, laboratory values, and electrocardiogram (ECG) waveforms as inputs to predict both discharge diagnoses and patient deterioration. Results: The diagnostic model achieves area under the receiver operating curve (AUROC) scores above 0.8 for 609 out of 1,428 conditions, covering both cardiac (e.g., myocardial infarction) and non-cardiac (e.g., renal disease, diabetes) diagnoses. The deterioration model attains AUROC scores above 0.8 for 14 out of 15 targets, accurately predicting critical events such as cardiac arrest, mechanical ventilation, ICU admission, and mortality. Conclusions: Our study highlights the positive impact of incorporating raw waveform data into decision support models, im

In the article, we present a Web-based System called M2LADS, which supports the integration and visualization of multimodal data recorded in user experiences (UX) in a Learning Analytics (LA) system in the form of Web-based Dashboards. Based on the edBB platform, the multimodal data gathered contains biometric and behavioral signals including electroencephalogram data to measure learners' cognitive attention, heart rate for affective measures and visual attention from the video recordings. Additionally, learners' static background data and their learning performance measures are tracked using LOGGE tool. M2LADS provides opportunities to capture learners' holistic experience during their interactions with the learning analytic system in order to improve the system and the user experience of the learners. -- En este artículo, presentamos M2LADS, un sistema que permite la integración y visualización de datos multimodales en forma de Dashboards Web. Estos datos provienen de sesiones de experiencia de usuario en un sistema de Learning Analytics (LA) llevadas a cabo por estudiantes de MOOCs. Los datos multimodales incluyen señales biométricas y de comportamiento monitorizados por la plat

Context. The discovery and tracking of 2018 LA marks only the third instance in history that the parent body of a fireball has been identified before its eventual disintegration in our atmosphere. The subsequent recovery of meteorites from 2018 LA was only the second time materials from outer space that reached the ground could be linked with certitude to a particular minor body. However, meteoroids like 2018 LA and its forerunners, 2008 TC3 and 2014 AA, are perhaps fragments of larger members of the near-Earth object (NEO) population. As the processes leading to the production of such fragments are unlikely to spawn just one meteoroid per event, it is important to identify putative siblings and plausible candidates from which the observed meteoroids might have originated. Aims. Here, we study the pre-impact orbital evolution of 2018 LA to place this meteoroid within the dynamical context of other NEOs that follow similar trajectories. Methods. Our statistical analyses are based on the results of direct N-body calculations that use the latest orbit determinations and include perturbations by the eight major planets, the Moon, the barycentre of the Pluto-Charon system, and the three

In this expository article, we study the relation between the boolean functions and the hypercontractivity theorems of Aline Bonami. We focus on the social choice theory, and present some of the most important results in the area, such as the Friedgut-Kalai-Naor (FKN) and the Kahn-Kalai-Linial (KKL) theorems, and the famous Fourier Entropy/Influence conjecture. -- En este artículo expositivo estudiamos la relación entre las funciones booleanas y los teoremas de hipercontractividad de Aline Bonami. Nos concentramos en la teoría de la elección social, y presentamos algunos de los resultados más importantes en el área como los teoremas de Friedgut-Kalai-Naor (FKN) y de Kahn-Kalai-Linial (KKL), y la famosa conjetura Entropíıa de Fourier/Influencia.

We compute the {\it exact} equation of state of circular strings in the (2+1) dimensional de Sitter (dS) and anti de Sitter (AdS) spacetimes, and analyze its properties for the different (oscillating, contracting and expanding) strings. The string equation of state has the perfect fluid form $P=(γ-1)E,$ with the pressure and energy expressed closely and completely in terms of elliptic functions, the instantaneous coefficient $γ$ depending on the elliptic modulus. We semi-classically quantize the oscillating circular strings. The string mass is $m=\sqrt{C}/(πHα'),\;C$ being the Casimir operator, $C=-L_{μν}L^{μν},$ of the $O(3,1)$-dS [$O(2,2)$-AdS] group, and $H$ is the Hubble constant. We find $α'm^2_{\mbox{dS}}\approx 5.9n,\;(n\in N_0),$ and a {\it finite} number of states $N_{\mbox{dS}}\approx 0.17/(H^2α')$ in de Sitter spacetime; $m^2_{\mbox{AdS}}\approx 4H^2n^2$ (large $n\in N_0$) and $N_{\mbox{AdS}}=\infty$ in anti de Sitter spacetime. The level spacing grows with $n$ in AdS spacetime, while is approximately constant (although larger than in Minkowski spacetime) in dS spacetime. The massive states in dS spacetime decay through tunnel effect and the semi-classical decay probabil