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Search Results: 1 - 10 of 489264 matches for " DANIEL AVILA A. "
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Primer registro de Oncopoduridae (Collembola: Entomobryomorpha) para Colombia
Revista Colombiana de Entomología , 2011,
Abstract: the family oncopoduridae (entomobryomorpha: arthropleona), represented by the species harlomillsia oculata, is reported for the first time in colombia. the samples were collected in blackberry crops and kikuyu grass pastures belonging to the andean high forest of the eastern cordillera at 2600 m elevation.
Primer registro de Oncopoduridae (Collembola: Entomobryomorpha) para Colombia First report of Oncopoduridae (Collembola: Entomobryomorpha) from Colombia
Revista Colombiana de Entomología , 2011,
Abstract: Se registra por primera vez para Colombia la familia Oncopoduridae (Entomobryomorpha: Arthropleona) representada por la especie Harlomillsia oculata. Los ejemplares se recolectaron en cultivo de mora y pastizal de kikuyo circunscritos a bosque alto andino de la cordillera oriental a 2600 msnm de altitud. The family Oncopoduridae (Entomobryomorpha: Arthropleona), represented by the species Harlomillsia oculata, is reported for the first time in Colombia. The samples were collected in blackberry crops and kikuyu grass pastures belonging to the Andean high forest of the eastern cordillera at 2600 m elevation.
Vibration Control of a Gym Floor Using Tuned Mass Dampers: A Numerical Analysis  [PDF]
Marcos Daniel Souza dos Santos, Daniel Valen?a Fiuza Lima, Jorge Eliécer Campuzano Carmona, Suzana Moreira Avila, Graciela Nora Doz de Carvalho
Modern Mechanical Engineering (MME) , 2013, DOI: 10.4236/mme.2013.33A002

This work presents a study on excessive vibration problem occurring on concrete slabs, usually used on residential and commercial building floors. Even well designed slabs, according to ultimate and serviceability limit states criteria, can be vulnerable to undesirable vibrations that lead to user discomfort. A gym floor, that presented real excessive vibrations, located in a commercial building situated in the city of Brasilia,Brazil, was analyzed via Finite Element Method using ANSYS software. The first step in this analysis was to obtain natural frequencies and vibration modes, the structure presented low natural frequencies representing its flexible behavior. Then it was simulated a dynamic loading of people jumping, characteristic of this type of building occupation. Since it was observed the occurrence of excessive vibrations also in the numerical analysis, a Tuned Mass Damper (TMD) control system was proposed, looking for the best set of dampers to improve the control performance. The parameters for the best vibration reduction were obtained via a parametric study considering four different slabs varying dimensions and support conditions. Different models considering one and more TMDs, varying its placements and parameters, besides the frequency reference value to tune the damper were considered. An efficient control solution to this practical problem is presented to reduce its undesirable vibrations.

Lipid Bodies: Inflammatory Organelles Implicated in Host-Trypanosoma cruzi Interplay during Innate Immune Responses
Heloisa D'Avila,Daniel A. M. Toledo,Rossana C. N. Melo
Mediators of Inflammation , 2012, DOI: 10.1155/2012/478601
Abstract: The flagellated protozoa Trypanosoma cruzi is the causal agent of Chagas' disease, a significant public health issue and still a major cause of morbidity and mortality in Latin America. Acute Chagas' disease elicits a strong inflammatory response. In order to control the parasite multiplication, cells of the monocytic lineage are highly mobilized. Monocyte differentiation leads to the formation of phagocytosing macrophages, which are strongly activated and direct host defense. A distinguishing feature of Chagas' disease-triggered macrophages is the presence of increased numbers of distinct cytoplasmic organelles termed lipid bodies or lipid droplets. These organelles are actively formed in response to the parasite and are sites for synthesis and storage of inflammatory mediators. This review covers current knowledge on lipid bodies elicited by the acute Chagas' disease within inflammatory macrophages and discusses the role of these organelles in inflammation. The increased knowledge of lipid bodies in pathogenic mechanisms of infections may not only contribute to the understanding of pathogen-host interactions but may also identify new targets for intervention.
Peripheral nervous system manifestations in a Sandhoff disease mouse model: nerve conduction, myelin structure, lipid analysis
Melanie A McNally, Rena C Baek, Robin L Avila, Thomas N Seyfried, Gary R Strichartz, Daniel A Kirschner
Journal of Negative Results in BioMedicine , 2007, DOI: 10.1186/1477-5751-6-8
Abstract: We detected no significant difference in signal impulse conduction velocity or any consistent change in the frequency-dependent conduction slowing and failure between freshly dissected sciatic nerves from the Hexb+/- and Hexb-/- mice. The low-angle x-ray diffraction patterns from freshly dissected sciatic and optic nerves of Hexb+/- and Hexb-/- mice showed normal myelin periods; however, Hexb-/- mice displayed a ~10% decrease in the relative amount of compact optic nerve myelin, which is consistent with the previously established reduction in myelin-enriched lipids (cerebrosides and sulfatides) in brains of Hexb-/- mice. Finally, analysis of lipid composition revealed that GM2 content was present in the sciatic nerve of the Hexb-/- mice (undetectable in Hexb+/-).Our findings demonstrate the absence of significant functional, structural, or compositional abnormalities in the peripheral nervous system of the murine model for Sandhoff disease, but do show the potential value of integrating multiple techniques to evaluate myelin structure and function in nervous system disorders.Gangliosides are a diverse class of glycosphingolipids (GSL) involved in cell-to-cell interactions, regulation of cell growth, apoptosis, neuritogenesis, and differentiation of cells [1]. Gangliosidoses, like Tay-Sachs, occur when these lipids are incompletely catabolized due to an inherited enzyme deficiency; GM2 gangliosidoses are characterized by incomplete GM2 catabolism due to the absence of β-hexosaminidase activity. The α- and β-subunits of β-hexosaminidase are encoded by the HEXA and HEXB genes. In non-pathogenic conditions, ganglioside GM2 is degraded to GM3 in the lysosome by the HexA isoenzyme combined with the GM2 activator protein. Without the activity of the HexA isoenzyme, massive lysosomal GM2 accumulation is observed which disrupts the normal cytoarchitecture of the neuronal cells [2]. Sandhoff disease (SD) is an inherited GM2 gangliosidosis that occurs in 1 of every 384,000 liv
Gene discovery in Triatoma infestans
María L Avila, Valeria Tekiel, Georgina Moretti, Soledad Nicosia, Jacqueline Bua, Estela M Lammel, María M Stroppa, Nelia de Burgos, Daniel O Sánchez
Parasites & Vectors , 2011, DOI: 10.1186/1756-3305-4-39
Abstract: In this work, we generated 826 ESTs, resulting in an increase of 47% in the number of ESTs available for T. infestans. These ESTs were assembled in 471 unique sequences, 151 of which represent 136 new genes for the Reduviidae family.Among the putative new genes for the Reduviidae family, we identified and described an interesting subset of genes involved in development and reproduction, which constitute potential targets for insecticide development.Chagas disease affects 8 million people, and ~28 million, in 21 endemic countries of Latin America, are at risk of infection [1]. The etiologic agent of Chagas disease is the parasite Trypanosoma cruzi, which is mainly transmitted through blood-sucking insect vectors of the Triatominae subfamily, being Triatoma infestans, Rhodnius prolixus, and Triatoma dimidiata the most epidemiologically important vectors. T. infestans is currently the main vector in the southern part of South America including regions of northern Argentina, Bolivia, Paraguay, and southern Peru. R. prolixus, on the other hand, is distributed in northern South America (mainly in Colombia and Venezuela) and has few foci in Central America. T. dimidiata, is present in Central America and Mexico, and also has limited foci in northern South America [2-4].Due to population migration from Latin America, Chagas disease is becoming an important health issue in North America, Europe and in the western Pacific region [5]. Currently, there are >390,000 individuals infected with T. cruzi in non-endemic regions and, accordingly, serological monitoring of blood banks and organ donors as well as additional controls to detect vertical transmission in newborns must be implemented to prevent the spread of the disease.As there are currently no vaccines available against T. cruzi and effective treatments are limited to chemotherapies that exhibit high toxicity, large efforts are being made to implement prevention strategies, such as domestic vector control and improvement o
Local and Landscape Factors Determining Occurrence of Phyllostomid Bats in Tropical Secondary Forests
Luis Daniel Avila-Cabadilla, Gerardo Arturo Sanchez-Azofeifa, Kathryn Elizabeth Stoner, Mariana Yolotl Alvarez-A?orve, Mauricio Quesada, Carlos Alonso Portillo-Quintero
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035228
Abstract: Neotropical forests are being increasingly replaced by a mosaic of patches of different successional stages, agricultural fields and pasture lands. Consequently, the identification of factors shaping the performance of taxa in anthropogenic landscapes is gaining importance, especially for taxa playing critical roles in ecosystem functioning. As phyllostomid bats provide important ecological services through seed dispersal, pollination and control of animal populations, in this study we assessed the relationships between phyllostomid occurrence and the variation in local and landscape level habitat attributes caused by disturbance. We mist-netted phyllostomids in 12 sites representing 4 successional stages of a tropical dry forest (initial, early, intermediate and late). We also quantitatively characterized the habitat attributes at the local (vegetation structure complexity) and the landscape level (forest cover, area and diversity of patches). Two focal scales were considered for landscape characterization: 500 and 1000 m. During 142 sampling nights, we captured 606 individuals representing 15 species and 4 broad guilds. Variation in phyllostomid assemblages, ensembles and populations was associated with variation in local and landscape habitat attributes, and this association was scale-dependent. Specifically, we found a marked guild-specific response, where the abundance of nectarivores tended to be negatively associated with the mean area of dry forest patches, while the abundance of frugivores was positively associated with the percentage of riparian forest. These results are explained by the prevalence of chiropterophilic species in the dry forest and of chiropterochorous species in the riparian forest. Our results indicate that different vegetation classes, as well as a multi-spatial scale approach must be considered for evaluating bat response to variation in landscape attributes. Moreover, for the long-term conservation of phyllostomids in anthropogenic landscapes, we must realize that the management of the habitat at the landscape level is as important as the conservation of particular forest fragments.
Phonon multiplexing through 1D chains
Avila, A.;Reyes, D.;
Brazilian Journal of Physics , 2008, DOI: 10.1590/S0103-97332008000500013
Abstract: recently, phonon propagation through atomic structures has become a relevant study issue. the most important applications arise in the thermal field, since phonons can carry thermal and acoustic energy. it is expected that technological advances will make possible the engineering of thermal paths according to convenience. a simple phonon multiplexer was analyzed as a spring-mass model. it consists of mono-atomic chains of atoms with a coupling structure between them. forces between atoms follow hooke's law and are restricted to be first nearest neighbor interaction. it was possible to establish simple rules on constitutive parameters such as atom masses and bonding forces that enable one to select a wavelength of transmission. the method used enables the study of structures of much greater complexity than the one presented here.
Propagation of the information in a one-way quantum computer
Avila, M.A.;
Revista mexicana de física E , 2007,
Abstract: both linear momentum and poynting vector associated with the propagation of information in a one-way quantum computer are studied. it is found that, within the so-called mean field theory (mft) approximation the total energy, the linear momentum and the poynting vector associated with the propagation of information are invariant under arbitrary rotations of logical qubits. this means that propagation of the quantum information stored in the entangled state does not depend on the choice of the quantum gates. due that the involved cluster of neighboring particles is large enough, last property satisfies the scalability test. as a consequence, quantum information in the one-way computer is read, written and processed independently of this choice, which suggests a simple hardware for it. when an external magnetic field is switched on, the invariance under arbitrary rotations of the logic qubits of these quantities is lost, that is, the field induces a preferential direction of propagation of the information which at the same time is optimized while more intense be the field.
A SPICE-compatible Model for Intel's 45nm High-K MOSFET
A. Avila,D. Espejo
Lecture Notes in Engineering and Computer Science , 2011,
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