Serrano L.,National Autonomous University of Mexico |
Ferrari L.,National Autonomous University of Mexico |
Martinez M.L.,Research Center Cientifica ucacion Superior Of Ensenada |
Petrone C.M.,University of Cambridge |
Jaramillo C.,Smithsonian Tropical Research Institute
Earth and Planetary Science Letters | Year: 2011
The genesis of the Caribbean Large Igneous Province (CLIP) has been associated to the melting of the Galapagos plume head at ~90Ma or to the interaction between the plume and the Caribbean slab window. Gorgona Island, offshore western Colombia, is an accreted fragment of the CLIP and its highly heterogeneous igneous suite, ranging from enriched basalts to depleted komatiites and picrites, was assumed to have formed at ~89Ma from different part of the plume. Here we present new geologic, geochronologic and geochemical data of Gorgona with significant implications for the formation of the CLIP. A new set of 40Ar-39Ar ages documents a magmatic activity spanning the whole Late Cretaceous (98.7±7.7 to 64.4±5Ma) followed by a shallower, picritic pyroclastic eruption in the Paleocene. Trace element and isotope geochemistry confirm the existence of an enriched (EDMM: La/SmN ≥1 and εNdi of 5.7 to 7.8) and a depleted (DMM: La/SmN<1 and εNdi of 9.5 to 11.3) mantle sources. A progressive increase in the degree of melting and melt extraction with time occurred in both groups. Petrologic modeling indicates that low but variable degrees of wet melting (<5%) of an EDMM can produce the LREE-enriched rocks. Higher degree of melting (>10%) of a mixed DMM+EDMM (40 to 60%) may reproduce the more depleted rocks with temperatures in the range of ambient mantle in absence of plumes. Our results contradict the notion that the CLIP formed by melting of a plume head at ~90Ma. Multiple magmatic pulses over several tens of Ma in small areas like Gorgona, also recognized in other CLIP areas, suggest a long period of diffuse magmatism without a clear pattern of migration. The age span of this magmatism is broadly concurrent with the Caribbean slab window. During this time span the Farallon oceanic lithosphere (later becoming the Caribbean plate) advanced eastward ~1500km, overriding the astenosphere feeding the proto-Caribbean spreading ridge. This hotter mantle flowed westward into, and mixed with, the opening mantle wedge, promoting increasing melting with time. The fortuitous occurrence of a plume passing through the slab gap area cannot be excluded but not required to produce the observed composition and degree of melting. © 2011 Elsevier B.V..
Zarate-De Landa A.,Research Center Cientifica ucacion Superior Of Ensenada |
Roblin P.,Ohio State University |
Reynoso-Hernandez J.A.,Research Center Cientifica ucacion Superior Of Ensenada |
IEEE Microwave and Wireless Components Letters | Year: 2012
Artificial neural networks are used as a tool in the development of reliable models for field effect transistors. This letter presents an improvement of the classical backpropagation algorithm allowing for the training process information contained in the first derivatives of I ds with respect to the control voltages V gs and V ds. Excellent agreement between measured and simulated data is achieved up to the third order derivative of I ds. © 2001-2012 IEEE.
Garcia-Ortiz C.E.,Autonomous University of Nuevo León |
Garcia-Ortiz C.E.,University of Southern Denmark |
Coello V.,Research Center Cientifica ucacion Superior Of Ensenada |
Han Z.,University of Southern Denmark |
And 2 more authors.
Optics Letters | Year: 2013
We demonstrate experimentally generation of diffraction-free plasmonic beams with zeroth- and first-order Bessel intensity profiles using axicon-like structures fabricated on gold film surfaces and designed to operate at a wavelength of 700 nm. The central beam features a very low divergence (∼8π mrad) for a narrow waist of the order of one wavelength and the ability to self reconstruct, which are the main signatures of diffraction-free beams. © 2013 Optical Society of America.
Kuzmiak V.,Academy of Sciences of the Czech Republic |
Maradudin A.A.,University of California at Irvine |
Mendez E.R.,Research Center Cientifica ucacion Superior Of Ensenada
Optics Letters | Year: 2014
The propagation of a surface plasmon polariton on a planar metal surface perturbed by N equally spaced rectangular grooves, each with the same width but with varying depths, is investigated by the finite-difference time-domain method. For a linear dependence of the depth of the nth groove on n, the transmissivity of the surface plasmon polariton and of the power radiated into the vacuum above the surface, as functions of its frequency, consist of N equally spaced dips and peaks, respectively. These are the signatures of the surface plasmon polariton analog of a Wannier-Stark ladder. © 2014 Optical Society of America.
Leal-Ramirez C.,Research Center Cientifica ucacion Superior Of Ensenada |
Echavarria-Heras H.,Research Center Cientifica ucacion Superior Of Ensenada
Scientific World Journal | Year: 2014
Despite the ecological importance of eelgrass, nowadays anthropogenic influences have produced deleterious effects in many meadows worldwide. Transplantation plots are commonly used as a feasible remediation scheme. The characterization of eelgrass biomass and its dynamics is an important input for the assessment of the overall status of both natural and transplanted populations. Particularly, in restoration plots it is desirable to obtain nondestructive assessments of these variables. Allometric models allow the expression of above ground biomass and productivity of eelgrass in terms of leaf area, which provides cost effective and nondestructive assessments. Leaf area in eelgrass can be conveniently obtained by the product of associated length and width. Although these variables can be directly measured on most sampled leaves, digital image methods could be adapted in order to simplify measurements. Nonetheless, since width to length ratios in eelgrass leaves could be even negligible, noise induced by leaf humidity content could produce misidentification of pixels along the peripheral contour of leaves images. In this paper, we present a procedure aimed to produce consistent estimations of eelgrass leaf area in the presence of the aforementioned noise effects. Our results show that digital image procedures can provide reliable, nondestructive estimations of eelgrass leaf area. © 2014 Cecilia Leal-Ramirez and Hector Echavarria-Heras.
Lavaniegos B.E.,Research Center Cientifica ucacion Superior Of Ensenada
Journal of Marine Systems | Year: 2014
The California Current system is a large marine ecosystem with transition gradients between subarctic and tropical biomes containing diverse habitats. Biogeographic species groups must be carefully analyzed in order to detect tendencies shifting the ecosystem toward a more temperate or tropical state. Species composition of hyperiid amphipods was analyzed in July 2002 for evidence of subarctic water intrusion and for signals of the El Niño event developing in the equatorial Pacific. Multivariate analysis showed a dominance of "transition zone" species typical of the California Current. The main evidence of subarctic water intrusion was the extended distribution of Themisto pacifica, which reached as far south as 27°N, with particularly high abundances at 30-32°N. The intrusion of subarctic water took place despite evidence that an El Niño event was in progress. The zonal advection due to El Niño intersected the equatorward flow of the subarctic intrusion and probably produced a large cyclonic eddy off Baja California. This eddy maintained a limited El Niño influence at a few offshore stations near its southern boundary. The main environmental variables influencing the amphipod assemblage structure were water temperature and the abundance of salps. T. pacifica, a species with cool water affinity, was more sensitive to temperature, whereas subtropical species, such as Vibilia armata, were strongly correlated with the availability of salps. © 2014 Elsevier B.V.
Rodrigo C.,Andrés Bello University |
Diaz J.,Pontifical Catholic University of Valparaíso |
Gonzalez-Fernandez A.,Research Center Cientifica ucacion Superior Of Ensenada
Latin American Journal of Aquatic Research | Year: 2014
The Easter submarine alignment corresponds to a sequence of seamounts and oceanic islands which runs from the Ahu-Umu volcanic fields in the west to its intersection with the Nazca Ridge in the east, with a total length of about 2.900 km and a strike of N85°E. Recent bathymetric compilations that include combined satellite derived and shipboard data (Global Topography) and multibeam bathymetric data (from NGDC-NOAA) are interpreted both qualitatively and quantitatively by using a morphological analysis, which was comprised of the determination of bathymetric patterns, trends in lineations and structures; height measurements, computation of basal areas and volumes of seamounts, in order to establish clues on the origin of this seamount chain and to establish relationships with the regional tectonics. In the study region 514 seamounts were counted, of which 334 had a basal area less than the reference seamount (Moai). In general, the largest seamounts (>1000 m in height) tend to align and to have a larger volume, with an elongation of their bases along the seamount chain. On the other hand, smaller seamounts tend to be distributed more randomly with more circular bases. As a consequence of the morphological analysis, the best possible mechanism that explains the origin of the seamount chain is the existence of a localized hotspot to the west of the Salas y Gómez Island. The corresponding plume would contribute additional magmatic material towards the East Pacific Rise through canalizations, whose secondary branches would feed intermediate volcanoes. It is possible that within the Easter Island region there would be another minor contribution through fractures in the crust, due to the crustal weakening that was produced by the Easter Fracture Zone. © 2014, Escuela de Ciencias del Mar. All rights reserved.
Evans R.,Research Center Cientifica ucacion Superior Of Ensenada
Energy Procedia | Year: 2014
In this paper we will present a newly written energy calculator built as a project between CICESE and the State Energy Commission of Baja California. The system runs server side and is written in PHP and Python storing its data on a My SQL database. The user interface allows the user to input their geographic location, and electrical energy use history. The user can then choose from a virtual warehouse of photovoltaic systems offered by local installers. Using astronomical algorithms, and weather station data the system generates a list of solar intensity values and calculates the response of chosen photovoltaic. The final values calculated are the cost predictions for the next 20 years. Because of its open-source nature, then system can be easily expanded to include wind power systems, carbon production, and ever gas and water usage. The primary user for this system is the general public with hopes that they will become educated on their energy use, and the potential effects of new photovoltaic installations. © 2014 The Authors. Published by Elsevier Ltd.
Tentori D.,Research Center Cientifica ucacion Superior Of Ensenada |
Garcia-Weidner A.,Research Center Cientifica ucacion Superior Of Ensenada
Optics Express | Year: 2013
In this work we analyze the birefringence matrix developed for a twisted fiber in order to identify the basic optical effects that define its birefringence. The study was performed using differential Jones calculus. The resultant differential matrix showed three independent types of birefringence: circular, linear at 0 degrees and linear at 45 degrees (Jones birefringence). We applied this birefringence matrix to the description of the output state of polarization measured for three commercial fibers that due to its higher rigidity present stronger birefringence changes when twisted. The torsion applied to the erbium-doped fiber samples varied from 0 to 1440 degrees. © 2013 Optical Society of America.
Sahay P.N.,Research Center Cientifica ucacion Superior Of Ensenada
Geophysics | Year: 2013
In a porous medium, the porosity perturbation, i.e., the change in porosity, is an integral part of a deformation process. Yet, there is no explicit statement about that in the Biot theory. By linking its constitutive relation to the continuity equations, the tacit assumption about the porosity perturbation in this theory is inferred. The linear dependence of the porosity perturbation on the pressure difference of the two phases is embedded in its constitutive relation. The solid and fluid pressures affect the change in porosity in equal magnitude but in opposite sense. By assuming that the fluid pressure may affect the porosity perturbation to an extent different than that of the solid pressure, the Biot constitutive relation is generalized. This introduces a nondimensional parameter. It could be named the porosity effective pressure coefficient, because the measure of the extent the fluid pressure affects the change in porosity relative to the solid pressure. In the regime in which the fluid pressure affects to a lesser extent, this parameter spans from unity, the state in which fluid resists the change in porosity in equal but opposite manner to solid, to zero, the state in which fluid ultimately ceases to affect the porosity change at all. As this parameter diminishes from unity, the undrained bulk modulus drops from being the Gassmann modulus. Ultimately, it becomes the series combination of the dry frame bulk modulus with the bulk modulus of fluid weighted by the Biot coefficient when the parameter is vanishing. The other regime is the one in which the fluid pressure affects to an extent greater than the solid pressure. Here, the parameter may span from unity to the ratio of bulk modulus of constituent solid mineral to fluid, which is its upper limit. At the upper limit, the undrained bulk modulus is the Voigt average: the upper bound of the modulus of a composite medium. © 2013 Society of Exploration Geophysicists.