Papers by Juan Sebastian Guancha Zapata
Lingüística y Literatura
Este artículo propone, a partir de un diálogo entre las propuestas teóricas de Pierre Bourdieu, J... more Este artículo propone, a partir de un diálogo entre las propuestas teóricas de Pierre Bourdieu, Jacques Dubois, Pascale Casanova y Rafael Gutiérrez Girardot, unas herramientas teóricas para analizar la trayectoria y la toma de posiciones estéticas, políticas y económicas del intelectual en función de su posición social. Dicha posición será analizada aquí a partir de tres momentos: en primer lugar, la posición del intelectual al interior de la institución cultural. En segundo lugar, la posición que la institución cultural ocupa al interior del campo del poder y, por último, la posición que la nación ocupa en la cartografía mundial de la producción cultural. Con esto en mente, se propone al final un esquema que engloba las posibles trayectorias del intelectual colombiano desde su aparición a finales del siglo XIX hasta el momento actual.
Rigorous mutual coupling analysis of open-ended radiating structures based on SFELP(segmentation technique/finite elements/Lanczos-Pade) and spherical modes
IEEE Antennas and Propagation Society International Symposium. Digest. Held in conjunction with: USNC/CNC/URSI North American Radio Sci. Meeting (Cat. No.03CH37450)
In this paper, properties of rotation and translation of spherical modes are used to study mutual... more In this paper, properties of rotation and translation of spherical modes are used to study mutual coupling between two open-ended radiating structures which can exhibit complex geometries. The isolated antennas are previously characterized by means of the SFELP methodology. The method is validated with measurements for two coupled apertures, and applied to cavity-backed microstrip antennas.
Estudios de Literatura Colombiana, 2018
Silva es considerado como una figura emblemática de los procesos de apropiación de las corrientes... more Silva es considerado como una figura emblemática de los procesos de apropiación de las corrientes artísticas que dieron origen al modernismo. Sin embargo, los pocos textos publicados durante su vida no permiten dar cuenta de dicho proceso de importación. Si aceptamos que existe en el poeta una voluntad de asimilar los modelos literarios provenientes de Europa, debemos contemplar la posibilidad de que la transferencia silvana se haya efectuado por otros soportes distintos a los libros o la prensa. Nuestra hipótesis es que el cenáculo se convirtió para el colombiano en el soporte ideal para desplegar una “postura” que encarnará los ideales estéticos de la modernidad literaria.
Literatura: teoría, historia, crítica, 2018
How did the banned and therefore suspect poet of The Flowers of Evil become the persecuted and mi... more How did the banned and therefore suspect poet of The Flowers of Evil become the persecuted and misunderstood author immortalized by literary history? How was Baudelaire able to turn a seemingly unfortunate situation to his advantage? Baudelaire was able to use the scandal triggered by the publication of The Flowers of Evil to promote his public persona. The analysis of the discursive postures deployed by Baudelaire before, during and after the trial will enable us to better understand how the poet inverted his condemnation, transforming the legal and moral sanctions, and the exclusion they entailed, into a sign of his greatness and posthumous glory.
Design of low cost cavity-backed microstrip patch arrays
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)
Page 1. DESIGN OF LOW COST CAVITY-BACKED MICROSTRIP PATCH ARRAYS Miguel A. Gonzalez', Jo... more Page 1. DESIGN OF LOW COST CAVITY-BACKED MICROSTRIP PATCH ARRAYS Miguel A. Gonzalez', Jose A. Encinar and Juan Zapata Dept de Electromagnetismo y Teoria de Circuitos, E TSI Telecomunicacion, UPM Ciudad Universitaria sin, 28040 Madrid (Spain). ...
Analysis of the scattering characteristics of finite arrays on an infinite ground plane based on finite elements and generalized scattering matrix
2005 IEEE Antennas and Propagation Society International Symposium
We achieve an efficient characterization of the scattering of electromagnetic plane waves from an... more We achieve an efficient characterization of the scattering of electromagnetic plane waves from antennas and cavities on an infinite ground plane as well as finite arrays. For this purpose the generalized scattering matrix approach is applied as an intermediate step to compute the transition matrix (T-matrix) that provides the scattering characteristics of the scatterers or radiating structures.
Bacteraemia by Ochrobactrum anthropi in patient with biliary obstruction
Reporte de caso de bacteriemia por Ochrobactrum anthropi con probable hepatitis bacteriana asocia... more Reporte de caso de bacteriemia por Ochrobactrum anthropi con probable hepatitis bacteriana asociada, en un paciente inmunocompetente, el cual ingresa por sospecha de colangitis y obstrucción biliar. O. anthropi es una bacteria emergente en infecciones intrahospitalarias con notable resistencia antimicrobiana, y es un patógeno inusual en humanos.
Biometric and Color Features Fusion for Face Detection and Tracking in Natural Video Sequences
Lecture Notes in Computer Science, 2007
ABSTRACT A system that performs the detection and tracking of a face in real-time in real video s... more ABSTRACT A system that performs the detection and tracking of a face in real-time in real video sequences is presented in this paper. The face is detected in a complex environment by a model of human colour skin. Very good results are obtained, since the colour segmentation removes almost all the complex background and it is realized to a very high-speed, making the system very robust. On the other hand, fast and stable real-time tracking is then achieved via biometric feature extraction of face using connected components labelling. Tracking does not require a precise initial fit of the model. Therefore, the system is initialised automatically using a very simple 2D face detector based on target ellipsoidal shape. Results are presented showing a significant improvement in detection rates when the whole sequence is used instead of a single image of the face. Experiments in tracking are reported.
Vaccine, 2008
A single injection of ML29 reassortant vaccine for Lassa fever induces low, transient viremia, an... more A single injection of ML29 reassortant vaccine for Lassa fever induces low, transient viremia, and low or moderate levels of ML29 replication in tissues of common marmosets depending on the dose of the vaccination. The vaccination elicits specific immune responses and completely protects marmosets against fatal disease by induction of sterilizing cell-mediated immunity. DNA array analysis of human peripheral blood mononuclear cells from healthy donors exposed to ML29 revealed that gene expression patterns in ML29-exposed PBMC and control, media-exposed PBMC, clustered together confirming safety profile of the ML29 in non-human primates. The ML29 reassortant is a promising vaccine candidate for Lassa fever.
Background: Rhesus macaques infected with lymphocytic choriomeningitis virus (LCMV) provide a mod... more Background: Rhesus macaques infected with lymphocytic choriomeningitis virus (LCMV) provide a model for human Lassa fever. Disease begins with flu-like symptoms and progresses rapidly with fatal consequences. Previously, we profiled the blood transcriptome of LCMV-infected monkeys (M. Djavani et al J. Virol. 2007) showing distinct pre-viremic and viremic stages that discriminated virulent from benign infections. In the present study, changes in liver gene expression from macaques infected with virulent LCMV-WE were compared to gene expression in uninfected monkeys as well as to monkeys that were infected but not diseased. Results: Based on a functional pathway analysis of differentially expressed genes, virulent LCMV-WE had a broader effect on liver cell function than did infection with non-virulent LCMV-Armstrong. During the first few days after infection, LCMV altered expression of genes associated with energy production, including fatty acid and glucose metabolism. The transcriptome profile resembled that of an organism in starvation: mRNA for acetyl-CoA carboxylase, a key enzyme of fatty acid synthesis was reduced while genes for enzymes in gluconeogenesis were up-regulated. Expression was also altered for genes associated with complement and coagulation cascades, and with signaling pathways involving STAT1 and TGF-β. Conclusion: Most of the 4500 differentially expressed transcripts represented a general response to both virulent and mild infections. However, approximately 250 of these transcripts had significantly different expression in virulent infections as compared to mild infections, with approximately 30 of these being differentially regulated during the pre-viremic stage of infection. The genes that are expressed early and differently in mild and virulent disease are potential biomarkers for prognosis and triage of acute viral disease. Background Arenaviruses are rodent-borne viruses that can be transmitted to primates, occasionally causing lethal hemor-rhagic fever. Arenaviruses causing Lassa fever and South American hemorrhagic fevers have been classified as Category A bio-threats in the United States because of their
Analysis of Cavity-Backed Multilayer Microstrip Patch Arrays on Continuous Dielectric Substrates by a Hybrid Modular Technique
31st European Microwave Conference, 2001, 2001
This work proposes a numerical procedure to analyse a novel cavity-backed microstrip array config... more This work proposes a numerical procedure to analyse a novel cavity-backed microstrip array configuration that combines both the conventional disposition of patches on continuous dielectric layers and patches enclosed in metallic cavities. Different numerical techniques are effectively combined to obtain a modular approach appropriate for designing complex multilayer structures. Additionally, and based on the application of this modular technique, results
Wireless Sensor Networks: Application-Centric Design, 2010
Full-wave analysis of the GALILEO System Navigation Antenna by means of the generalized scattering matrix of a finite array
2006 First European Conference on Antennas and Propagation, 2006
A full-wave methodology has been used to analyse the GALILEO system navigation antenna for the sp... more A full-wave methodology has been used to analyse the GALILEO system navigation antenna for the space segment of the global positioning system. It is a multilayer array structure composed by cavity-backed microstrip patches in stacked configuration, and coaxial probe feeding. It follows a hexagonal regular lattice that makes possible to perform a modular analysis in two steps. First, each isolated
Viruses, 2013
Arenavirus particles are enveloped and contain two single-strand RNA genomic segments with ambise... more Arenavirus particles are enveloped and contain two single-strand RNA genomic segments with ambisense coding. Genetic plasticity of the arenaviruses comes from transcription errors, segment reassortment, and permissive genomic packaging, and results in their remarkable ability, as a group, to infect a wide variety of hosts. In this review, we discuss some in vitro studies of virus genetic and phenotypic variation after exposure to selective pressures such as high viral dose, mutagens and antivirals. Additionally, we discuss the variation in vivo of selected isolates of Old World arenaviruses, particularly after infection of different animal species. We also discuss the recent emergence of new arenaviruses in the context of our observations of sequence variations that appear to be host-specific.
Agenda De Investigación, Desarrollo Tecnológico e Innovación Para Los Servicios Sociales De La Gobernación De …
Antes que nada, es preciso señalar que los condicionantes de la salud humana abarcan todos los ca... more Antes que nada, es preciso señalar que los condicionantes de la salud humana abarcan todos los campos de la vida, la ciencia, tecnología, cultura y ambiente; es decir, prácticamente todo. De allí que sea ambicioso presentar en un trabajo del alcance ...
Microwave and Optical Technology Letters, 2001
Figure 5 Measured antenna gains for the antenna studied in Fig-Ž. Ž. ure 2 with ␣ s 12Њ. a f s 18... more Figure 5 Measured antenna gains for the antenna studied in Fig-Ž. Ž. ure 2 with ␣ s 12Њ. a f s 1875 MHz. b f s 2100 MHz 1 2 by inserting two narrow slits at one of the radiating edges of the patch. The two operating frequencies have the same polarization planes, and the frequency ratio of the two frequencies is tunable from 1.08 to 1.17 by varying the flare angle of the trapezoid microstrip-line section. In addition, the optimal feed positions are found to be insensitive to the variation in the flare angle, which makes the present design easy to implement.
Journal of Virology, 2005
Lassa virus (LASV) and Mopeia virus (MOPV) are closely related Old World arenaviruses that can ex... more Lassa virus (LASV) and Mopeia virus (MOPV) are closely related Old World arenaviruses that can exchange genomic segments (reassort) during coinfection. Clone ML29, selected from a library of MOPV/LASV (MOP/LAS) reassortants, encodes the major antigens (nucleocapsid and glycoprotein) of LASV and the RNA polymerase and zinc-binding protein of MOPV. Replication of ML29 was attenuated in guinea pigs and nonhuman primates. In murine adoptive-transfer experiments, as little as 150 PFU of ML29 induced protective cell-mediated immunity. All strain 13 guinea pigs vaccinated with clone ML29 survived at least 70 days after LASV challenge without either disease signs or histological lesions. Rhesus macaques inoculated with clone ML29 developed primary virus-specific T cells capable of secreting gamma interferon in response to homologous MOP/LAS and heterologous MOPV and lymphocytic choriomeningitis virus. Detailed examination of two rhesus macaques infected with this MOPV/LAS reassortant reveal...
B2 Enhancing Cellular Immune Responses to SIV Gag DNA Vaccine by Suppressing Fas-FasL Signaling
JAIDS Journal of Acquired Immune Deficiency Syndromes, 2012
ABSTRACT The biggest hurdle for clinical trials with DNA vaccines is low immunogenicity. The effe... more ABSTRACT The biggest hurdle for clinical trials with DNA vaccines is low immunogenicity. The effects of apoptotic death on immunogenicity have been studied intensively during the last decade, but some controversial data make it very confusing. We hypothesized that inhibiting the Fas-FasL signaling pathway would enhance DNA vaccine potency. Using SIVmac gag as a model antigen, we co-injected C57BL/6J mice intramuscularly with plasmids expressing pro- or anti-apoptotic molecules, followed immediately by electroporation. Anti-apoptotic molecules (shRNA targeting Fas and FasL, cFLIP) and the pro-apoptotic molecules (FADD and Fas) have been used so far. Our pilot studies showed that the dose and ratio between antigen plasmid and apoptosis modifier were two key factors that influence cellular immune responses (CMI) to SIVmac gag. We were able to extend and confirm the findings from Norman Letvin's group (Greenland John et al, 2007) that Fas KO mice developed much better CMI (both quality and quantity) to gag than wild-type C57 BL/6J mice. Co-injection of mice with plasmids expressing SIVmac gag and any of the anti-apoptotic molecules at the ratio of 1:1 developed better CMI than injecting antigen plasmid alone. However, the pro-apoptotic molecules Fas and FADD significantly inhibited the cellular immune responses under the same conditions. Taken together, inhibition of the Fas-FasL signaling pathway has positive effect on primary DNA vaccine immunity but seems to have stronger effects on memory responses.
IEEE Transactions on Microwave Theory and Techniques, 1996
In this paper a finite element formulation in terms of the magnetic field is presented for the an... more In this paper a finite element formulation in terms of the magnetic field is presented for the analysis of waveguides with bianisotropic media. Such a formulation can deal with lossy inhomogeneous materials characterized by simultaneous permittivity, permeability, and cross-coupling (as in optical activity) arbitrary full tensors. The analysis takes into account arbitrary cross sections, and results in spurious-mode suppression, complex-mode computation, and the possibility of alternatively specifying the frequency or the complex propagation constant as an input parameter. In this way, many novel classes of waveguides with promising applications, such as chirowaveguides and chiroferrite-waveguides, can be analyzed. The formulation leads to a quadratic sparse eigenvalue problem which is transformed into a sparse generalized eigenvalue problem. This eigensystem is solved by the subspace method, the sparsity of the matrices being fully utilized. The proposed method has been validated by analyzing waveguides with biisotropic and bianisotropic materials. The agreement with previously published data is found to be excellent.
Full-wave design and realization of multicoupled dual-mode circular waveguide filters
IEEE Transactions on Microwave Theory and Techniques, 1995
Abstract-A new full-wave method for the design and real-ization of dual-mode circular waveguide f... more Abstract-A new full-wave method for the design and real-ization of dual-mode circular waveguide filters is presented. The rigorous CAD is a combination of the mode-matching and the finite-element techniques, which permits obtaining the Gener-alized Scattering Matrix for all the blocks ...
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Papers by Juan Sebastian Guancha Zapata