44 research outputs found
Dynamics of Annihilation II: Fluctuations of Global Quantities
We develop a theory for fluctuations and correlations in a gas evolving under
ballistic annihilation dynamics. Starting from the hierarchy of equations
governing the evolution of microscopic densities in phase space, we
subsequently restrict to a regime of spatial homogeneity, and obtain explicit
predictions for the fluctuations and time correlation of the total number of
particles, total linear momentum and total kinetic energy. Cross-correlations
between these quantities are worked out as well. These predictions are
successfully tested against Molecular Dynamics and Monte-Carlo simulations.
This provides strong support for the theoretical approach developed, including
the hydrodynamic treatment of the spectrum of the linearized Boltzmann
operator. This article is a companion paper to arXiv:0801.2299 and makes use of
the spectral analysis reported there.Comment: 19 page
Técnicas didácticas: método de caso clínico con la utilización de video como herramienta de apoyo en la enseñanza de la medicina
Teaching techniques: clinical case approach to the use of video as a tool to supportRESUMENLa enseñanza de las ciencias biomédicas o denominadas también básicas, en los programas de medicina de las Universidades de Colombia, es la base fundamental para el desarrollo continuo del razonamiento científico y clínico en los futuros profesionales facultativos para la evolución social y científica del país. La evaluación autónoma de la calidad interna, por parte de las instituciones educativas, se hace imprescindible para lograr, no sólo, la adquisición de conocimientos fácticos en forma significativa, sino también, la formación ética, estética y humanística de los estudiantes. La enseñanza y el aprendizaje de las ciencias Biomédicas implican aspectos teóricos, metodológicos e investigativos, así como una reflexión constante sobre el quehacer pedagógico, lo que implica la interdisciplinaridad, la integración básicoclínica y, por extensión, la didáctica y la aplicación de tecnologías de la información y la comunicación (TIC). En este escrito, se expone una experiencia pedagógica de tipo cualitativo fundamentada en Método de Caso Clínico (MdC), la cual se llevó a cabo dentro de la sección de Bioclínica de la Universidad El Bosque, se estructuró con el uso de TIC y se basó en un problema de impacto de morbilidad de Salud Pública para Colombia.Palabras clave: Aprendizaje, Ciencias Biomédicas, Didáctica, Enseñanza, Medicina, Método de casos (Estudio de casos), PedagogíaABSTRACTThe teaching of biomedical sciences or also called basic medical programs at the Universities of Colombia, is the fundamental basis for the continued development of scientific reasoning and clinical professionals in future physicians, and therefore to the social and scientific the country. Therefore, the independent evaluation of internal quality by educational institutions is essential to achieve not only the acquisition of factual knowledge significantly, but also the ethical, aesthetic and humanistic students. Teaching and learning science involves Biomedical theoretical, methodological and research and a constant reflection on the pedagogical practice, which involves interdisciplinary, basic clinical integration, and by extension the teaching and application of new Information and Communication Technology (ICT). In this paper, presents a qualitative learning experience based on Clinical Case Method (MdC), which was held in the section Bioclinic of the University El Bosque, and was structured with the use of TICS and which was based on a problem of impact of disease of public health for Colombia.Keywords: Case method (Case system), Biomedical science, Education, Learning, Medicine, Pedagogy, Teaching
Técnicas didácticas: método de caso clínico con la utilización de video como herramienta de apoyo en la enseñanza de la medicina
Teaching techniques: clinical case approach to the use of video as a tool to supportRESUMENLa enseñanza de las ciencias biomédicas o denominadas también básicas, en los programas de medicina de las Universidades de Colombia, es la base fundamental para el desarrollo continuo del razonamiento científico y clínico en los futuros profesionales facultativos para la evolución social y científica del país. La evaluación autónoma de la calidad interna, por parte de las instituciones educativas, se hace imprescindible para lograr, no sólo, la adquisición de conocimientos fácticos en forma significativa, sino también, la formación ética, estética y humanística de los estudiantes. La enseñanza y el aprendizaje de las ciencias Biomédicas implican aspectos teóricos, metodológicos e investigativos, así como una reflexión constante sobre el quehacer pedagógico, lo que implica la interdisciplinaridad, la integración básicoclínica y, por extensión, la didáctica y la aplicación de tecnologías de la información y la comunicación (TIC). En este escrito, se expone una experiencia pedagógica de tipo cualitativo fundamentada en Método de Caso Clínico (MdC), la cual se llevó a cabo dentro de la sección de Bioclínica de la Universidad El Bosque, se estructuró con el uso de TIC y se basó en un problema de impacto de morbilidad de Salud Pública para Colombia.Palabras clave: Aprendizaje, Ciencias Biomédicas, Didáctica, Enseñanza, Medicina, Método de casos (Estudio de casos), PedagogíaABSTRACTThe teaching of biomedical sciences or also called basic medical programs at the Universities of Colombia, is the fundamental basis for the continued development of scientific reasoning and clinical professionals in future physicians, and therefore to the social and scientific the country. Therefore, the independent evaluation of internal quality by educational institutions is essential to achieve not only the acquisition of factual knowledge significantly, but also the ethical, aesthetic and humanistic students. Teaching and learning science involves Biomedical theoretical, methodological and research and a constant reflection on the pedagogical practice, which involves interdisciplinary, basic clinical integration, and by extension the teaching and application of new Information and Communication Technology (ICT). In this paper, presents a qualitative learning experience based on Clinical Case Method (MdC), which was held in the section Bioclinic of the University El Bosque, and was structured with the use of TICS and which was based on a problem of impact of disease of public health for Colombia.Keywords: Case method (Case system), Biomedical science, Education, Learning, Medicine, Pedagogy, Teaching
Factores de Crecimiento Epitelial: Aspectos Biológicos, Patológicos y Clínicos
RESUMEN Los Factores de Crecimiento son mediadores de comunicación celular con un papel vital en el comportamiento normal y patológico celular, tisular y sistémico, de los organismos vivos. Dentro de ellos la familia de los EGF(Factor de Crecimiento Epitelial) son elementos claves en la fisiología celular no sólo celular epitelial, sino también en otros tipos celulares, regulando procesos morfogénicos a varios niveles. Es el objetivo de esta revisión es describir el estado del arte de esta familia de factores de crecimiento tanto en la normalidad como en sus aspectos patológicos. Palabras Claves: Esquizofrenia, Factor de Crecimiento, EGF(Factor de Crecimiento Epitelial), Neuregulinas, Neurodegeneración, Neoplasia, Cáncer, Carcinoma ABSTRACT The growth factors are comunication cell mediators with a vital roll in the normal and pathologic comportament cell, tissue and systemic, in life organism. Into of they, the EGF(Epidermal Growth Factor) family are principal elements in the cell physiology, no only of epithelial cell, so too in others cell types, regulating morphogenic process in diverse nivels. Is the objetive of this revision to summary the corrient knowledge of this family, in the normality as in pathologic aspects. Key Words: Growth Factor, EGF(Epidermal Growth Factor), Schizophrenia, Neurodegeneration, Neuregulin, Neoplasia, Cancer, Carcinom
Factores de Crecimiento Epitelial: Aspectos Biológicos, Patológicos y Clínicos
RESUMEN Los Factores de Crecimiento son mediadores de comunicación celular con un papel vital en el comportamiento normal y patológico celular, tisular y sistémico, de los organismos vivos. Dentro de ellos la familia de los EGF(Factor de Crecimiento Epitelial) son elementos claves en la fisiología celular no sólo celular epitelial, sino también en otros tipos celulares, regulando procesos morfogénicos a varios niveles. Es el objetivo de esta revisión es describir el estado del arte de esta familia de factores de crecimiento tanto en la normalidad como en sus aspectos patológicos. Palabras Claves: Esquizofrenia, Factor de Crecimiento, EGF(Factor de Crecimiento Epitelial), Neuregulinas, Neurodegeneración, Neoplasia, Cáncer, Carcinoma ABSTRACT The growth factors are comunication cell mediators with a vital roll in the normal and pathologic comportament cell, tissue and systemic, in life organism. Into of they, the EGF(Epidermal Growth Factor) family are principal elements in the cell physiology, no only of epithelial cell, so too in others cell types, regulating morphogenic process in diverse nivels. Is the objetive of this revision to summary the corrient knowledge of this family, in the normality as in pathologic aspects. Key Words: Growth Factor, EGF(Epidermal Growth Factor), Schizophrenia, Neurodegeneration, Neuregulin, Neoplasia, Cancer, Carcinom
Applications in energy and environment of nanocolumnar films
Resumen del trabajo presentado en el CMD30-FisMat 2023 celebrado en Milán (Italia), del 4 al 8 de septiembre de 2023Glancing Angle Deposition (GLAD) with magnetron sputtering (MS) is an easy and versatile route to fabricate nanocolumnar films in large areas (several cm2
and above) in
a single-step process, in clear contrast to other techniques in the nanoscale range such as e-beam lithography and ion-beam lithography. The morphology of the nanocolumns
can be controlled depending on several parameters such as the gas pressure, the angle of inclination of the substrate and its possible rotation, the electromagnetic power, the
deposition time, and the optional use of collimating masks [1-4]. Moreover, as GLAD with MS it is usually carried out at RT and does not involve chemical products (thus,
without associated recycling issues), this technique is environmentally friendly. In this talk, I will start explaining the fundamentals of GLAD with MS and then I will
present some recent examples of nanocolumnar films that are of interest in the field of energy and environment: Gold nanocolumnar templates for effective chemical sensing
by surface-enhanced Raman scattering [5], Iron nanocolumnar films with tailored magnetic behavior [6], and Titanium oxide nanocolumnar films that exhibit photo‐induced
self‐cleaning properties [7]. It will be finally shown that this latter effect can be enhanced when the nanocolumns are decorated with gold nanoparticles using a gas
aggregation source that is also based on MS. References:[1] R. Alvarez et al., Nanotechnology 24, 045604 (2013). [2] R. Alvarez et al., J. Phys. D: Appl. Phys. 49, 045303
(2016). [3] A. Vitrey et al., Beilstein J. Nanotechnol. 8, 434 (2017).[4] G. Troncoso et al., Appl. Surf. Sci. 526, 146699 (2020).[5] G. Barbillon et al., Nanomaterials 12, 4157
(2022).[6] E. Navarro et al., Nanomaterials 12, 1186 (2022).[7] F. Fresno et al., Adv. Sustainable Syst. 5, 2100071 (2021)
A unified vegetation index for quantifying the terrestrial biosphere
[EN] Empirical vegetation indices derived from spectral reflectance data are widely used in remote sensing of the biosphere, as they represent robust proxies for canopy structure, leaf pigment content, and, subsequently, plant photosynthetic potential. Here, we generalize the broad family of commonly used vegetation indices by exploiting all higher-order relations between the spectral channels involved. This results in a higher sensitivity to vegetation biophysical and physiological parameters. The presented nonlinear generalization of the celebrated normalized difference vegetation index (NDVI) consistently improves accuracy in monitoring key parameters, such as leaf area index, gross primary productivity, and sun-induced chlorophyll fluorescence. Results suggest that the statistical approach maximally exploits the spectral information and addresses long-standing problems in satellite Earth Observation of the terrestrial biosphere. The nonlinear NDVI will allow more accurate measures of terrestrial carbon source/sink dynamics and potentials for stabilizing atmospheric CO2 and mitigating global climate change.G.C.-V. was supported by the European Research Council (ERC) under the ERC Consolidator Grant 2014 project SEDAL (647423). M.C.-T. and F.J.G.-H. were supported by the EUMETSAT Satellite Application Facility on Land Surface Analysis (LSA-SAF). SR research was financially supported by the NASA Earth Observing System MODIS project (grant NNX08AG87A). J.A.G. acknowledges the support of NASA ABoVE award number NNX15AT78A. S.W. acknowledges funding from the Emmy Noether Programme (GlobFluo project) of the German Research Foundation (GU 1276/1-1) as well as funding from the European Union's Horizon 2020 research and innovation program under grant agreement 776186 (CHE project) and agreement 776810 (VERIFY project).Camps-Valls, G.; Campos-Taberner, M.; Moreno-Martínez, Á.; Walther, S.; Duveiller, G.; Cescatti, A.; Mahecha, MD.... (2021). A unified vegetation index for quantifying the terrestrial biosphere. Science Advances. 7(9):1-11. https://doi.org/10.1126/sciadv.abc74471117
TRY plant trait database – enhanced coverage and open access
Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level
Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network
Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects