• Title, Summary, Keyword: Mexico

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Penetrating Cardiac Injury and Traumatic Pericardial Effusion Caused by a Nail Gun

  • Miranda, Willem Guillermo Calderon;Fuentes, Edgardo Jimenez;Hernandez, Nidia Escobar;Salazar, Luis Rafael Moscote;Parizel, Paul M.
    • Journal of Trauma and Injury
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    • v.30 no.1
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    • pp.21-23
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    • 2017
  • Penetrating cardiac injury caused by nail gun is an uncommon life-threatening condition characterized by a rapidly severe hemodynamic status compromise. We report non-contrast-enhanced CT findings of a right ventricle myocardium injury leading to a fluid collection in the pericardial space with the same attenuation as blood. The CT findings well depicted the pathological feature of a significant cardiac injury and may be helpful for the surgical management.

Ceramium riosmenae sp. nov. (Ceramiaceae, Rhodophyta): a new complete corticated species on Gracilaria from Baja California Sur, Mexico

  • Won, Boo-Yeon;Cho, Tae-Oh
    • ALGAE
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    • v.26 no.4
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    • pp.289-297
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    • 2011
  • Ceramium riosmenae sp. nov. is described from Baja California Sur, Mexico based on morphological and molecular data. The new species is characterized by erect thalli only, penetrating rhizoids on Gracilaria, 7-8 periaxial cells, five cortical initials per periaxial cell, complete cortication throughout, an average of 11-12 segments between branching points, rare adventitious branchlets, and cruciate tetrasporangia. Although C. riosmenae sp. nov. is similar to C. interruptum, C. sinicola, and C. codicola reported from Baja California Sur, Mexico in size and habit, it differs from these species in the number of cortical initials, habit, degree of cortication, host, and the shape of rhizoidal tips. C. riosmenae is separated from C. interruptum with interrupted cortication and four cortical initials from C. sinicola with spins near the apex and incomplete cortication near the base and from C. codicola with bulbous rhizoids on Codium. Our rbcL sequences reveal sufficient sequence divergence (2.4-3.9%) between C. riosmenae and C. interruptum, C. sinicola, and C. codicola to warrant species recognition and to separate C. riosmenae from these species on a phylogenetic tree.

A Study on the Growth and Exchange of Cotton during the Classic Mesoamerica

  • Ahn, Cheun-Soon
    • The International Journal of Costume Culture
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    • v.12 no.2
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    • pp.153-162
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    • 2009
  • This paper introduces the probable regional and long distance trade of cotton goods among the pre-Hispanic Mesoamericans during the Classic (A.D. 200-900) period through the comparison of the available documentary sources. Based on the ethnohistoric data and the archaeological evidences it was found that cotton was used throughout the Mesoamerica by the elite ruling class. However, because cotton could not be grown at elevations above 6,000 feet it was obvious that nations such as Teotihuacan which flourished in the highland of present day Mexico City had to import cotton from the tropical coastal hotlands either through trade or tribute. Several ethnohistorical and archaeological data suggest that urban center in highland Mexico had people employed in weaving the textiles rather than cultivating or spinning cotton. Archaeological evidences such as the workshops used by the craft specialists seemed to be associated with weaving of cotton. Because of the similarity in climatic conditions for marine shells and cotton cultivation, Kolb's model seems to be applicable to the cotton trade of the classic Teotihuacan. Based on Kolb's model, it could be hypothesized that Teotihuacan-Kaminaljyyu-Maya was the indirect trade route connecting the Basin of Mexico and the Mayan regions.

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First Record of Ulva pertusa Kjellman (Ulvales, Chlorophyta) in the Pacific Coast of Mexico

  • Aguilar-Rosasl, Racal;Aguilar-Rosas, Luis E.;Shimada, Satoshi
    • ALGAE
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    • v.23 no.3
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    • pp.201-207
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    • 2008
  • Based on samplings during 2006-2007 on the intertidal zone of Playa Tampico, Eréndira and Punta Baja, Baja California, Ulva pertusa Kjellman (Ulvales, Chlorophyta) was recorded for the first time for the Pacific coast of Mexico. An alga native to Asia, U. pertusa has just recently been recorded in the southern coast of California (USA). The identification of U. pertusa was based on the observation of the morphology and reproductive characters of the collected specimens. Furthermore, the species identity was confirmed by molecular comparison between nuclearencoded ITS2 sequences of the Mexican samples and those of other Ulva species in GenBnak data. Habitat and distribution of U. pertusa along the Pacific coast of North America are also described. Considering our new report of its occurrence in Mexico, we conclude that U. pertusa is expanding its geographical distribution by trans-ocean introductions.

On Output Feedback Tracking Control of Robot Manipulators with Bounded Torque Input

  • Moreno-Valenzuela, Javier;Santibanez, Victor;Campa, Ricardo
    • International Journal of Control, Automation, and Systems
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    • v.6 no.1
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    • pp.76-85
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    • 2008
  • Motivated by the fact that in many industrial robots the joint velocity is estimated from position measurements, the trajectory tracking of robot manipulators with output feedback is addressed in this paper. The fact that robot actuators have limited power is also taken into account. Let us notice that few solutions for the torque-bounded output feedback tracking control problem have been proposed. In this paper we contribute to this subject by presenting a theoretical reexamination of a known controller, by using the theory of singularly perturbed systems. Motivated by this analysis, a redesign of that controller is introduced. As another contribution, we present an experimental evaluation in a two degrees-of-freedom revolute-joint direct-drive robot, confirming the practical feasibility of the proposed approach.

New Records of Marine Rhodophyta from the Pacific Coast of Mexico

  • Aguilar-Rosas, Raul;Aguilar-Rosas , Luis E.;Mateo-Cid, Luz Elena;Mendoza-Gonzalez, Catalina
    • ALGAE
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    • v.22 no.3
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    • pp.153-157
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    • 2007
  • Two species of marine red algae, Jania ungulata (Yendo) Yendo f. brevior (Yendo) Yendo and Peyssonnelia japonica (Segawa) Yoneshigue (Rhodophyta) were collected for the first time from Mexican Pacific coast. Their vegetative and reproductive structures are described, as well as the habitat where they were found and their geographical distribution along the Pacific coasts of Mexico. Jania ungulata f. brevior is a commonly growing epiphytic and Peyssonnelia japonica is epiphyte. The fact that we found this new records in Mexican coast is noteworthy, due that this species are originally described in Japanese coast. The absence of records of this species in the Mexican coast is likely related in part to the lack of specific collections and the fact that the specimens are small and delicate, and may commonly be unnoticed during samplings.

Morphometrics of Scinaia latifrons (Nemaliales, Rhodophyta) in the Southwestern Gulf of California, Mexico

  • Leon-Cisneros, Karla;Riosmena-Rodriguez, Rafael
    • ALGAE
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    • v.20 no.1
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    • pp.31-36
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    • 2005
  • Scinaia latifrons Howe occurs in rhodolith beds between 9 to 27 m depths at San Lorenzo channel, Gulf of California, Mexico. As very little was known about the morphometrics of this normally temperate species in a subtropical area, we investigated the phenological changes from December 1998 to December 1999. The gametophytic phase of the species was present from late February to late May, which represented a shorter time period to other known species in the genus. Our results suggested that two gametophytic cohorts develop over winter and early spring based on the size class structure of the frond height. Thalli became reproductively mature at a small size (1-2 cm in height) and all the plants were monoecious. Scinaia latifrons at the study location underwent allometric growth, indicated by the lack of correlation between size, width of the plants, or branching patterns.

A homogenization approach for uncertainty quantification of deflection in reinforced concrete beams considering microstructural variability

  • Kim, Jung J.;Fan, Tai;Reda Taha, Mahmoud M.
    • Structural Engineering and Mechanics
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    • v.38 no.4
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    • pp.503-516
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    • 2011
  • Uncertainty in concrete properties, including concrete modulus of elasticity and modulus of rupture, are predicted by developing a microstructural homogenization model. The homogenization model is developed by analyzing a concrete representative volume element (RVE) using the finite element (FE) method. The concrete RVE considers concrete as a three phase composite material including: cement paste, aggregate and interfacial transition zone (ITZ). The homogenization model allows for considering two sources of variability in concrete, randomly dispersed aggregates in the concrete matrix and uncertain mechanical properties of composite phases of concrete. Using the proposed homogenization technique, the uncertainty in concrete modulus of elasticity and modulus of rupture (described by numerical cumulative probability density function) are determined. Deflection uncertainty of reinforced concrete (RC) beams, propagated from uncertainties in concrete properties, is quantified using Monte Carlo (MC) simulation. Cracked plane frame analysis is used to account for tension stiffening in concrete. Concrete homogenization enables a unique opportunity to bridge the gap between concrete materials and structural modeling, which is necessary for realistic serviceability prediction.

Entropy-based optimal sensor networks for structural health monitoring of a cable-stayed bridge

  • Azarbayejani, M.;El-Osery, A.I.;Taha, M.M. Reda
    • Smart Structures and Systems
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    • v.5 no.4
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    • pp.369-379
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    • 2009
  • The sudden collapse of Interstate 35 Bridge in Minneapolis gave a wake-up call to US municipalities to re-evaluate aging bridges. In this situation, structural health monitoring (SHM) technology can provide the essential help needed for monitoring and maintaining the nation's infrastructure. Monitoring long span bridges such as cable-stayed bridges effectively requires the use of a large number of sensors. In this article, we introduce a probabilistic approach to identify optimal locations of sensors to enhance damage detection. Probability distribution functions are established using an artificial neural network trained using a priori knowledge of damage locations. The optimal number of sensors is identified using multi-objective optimization that simultaneously considers information entropy and sensor cost-objective functions. Luling Bridge, a cable-stayed bridge over the Mississippi River, is selected as a case study to demonstrate the efficiency of the proposed approach.

Biochemical Characterization of Recombinant L-Asparaginase (AnsA) from Rhizobium etli, a Member of an Increasing Rhizobial-Type Family of L-Asparaginases

  • Moreno-Enriquez, Angelica;Evangelista-Martinez, Zahaed;Gonzalez-Mondragon, Edith G.;Calderon-Flores, Arturo;Arreguin, Roberto;Perez-Rueda, Ernesto;Huerta-Saquero, Alejandro
    • Journal of Microbiology and Biotechnology
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    • v.22 no.3
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    • pp.292-300
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    • 2012
  • We report the expression, purification, and characterization of L-asparaginase (AnsA) from Rhizobium etli. The enzyme was purified to homogeneity in a single-step procedure involving affinity chromatography, and the kinetic parameters $K_m$, $V_{max}$, and $k_{cat}$ for L-asparagine were determined. The enzymatic activity in the presence of a number of substrates and metal ions was investigated. The molecular mass of the enzyme was 47 kDa by SDS-PAGE. The enzyme showed a maximal activity at $50^{\circ}C$, but the optimal temperature of activity was $37^{\circ}C$. It also showed maximal and optimal activities at pH 9.0. The values of $K_m$, $V_{max}$, $k_{cat}$, and $k_{cat}/K_m$ were $8.9{\pm}0.967{\times}10^{-3}$ M, $128{\pm}2.8$ U/mg protein, $106{\pm}2s^{-1}$, and $1.2{\pm}0.105{\times}10^4M^{-1}s^{-1}$, respectively. The L-asparaginase activity was reduced in the presence of $Mn^{2+}$, $Zn^{2+}$, $Ca^{2+}$, and $Mg^{2+}$ metal ions for about 52% to 31%. In addition, we found that $NH_4{^+}$, L-Asp, D-Asn, and ${\beta}$-aspartyl-hydroxamate in the reaction buffer reduced the activity of the enzyme, whereas L-Gln did not modify its enzymatic activity. This is the first report on the expression and characterization of the L-asparaginase (AnsA) from R. etli. Phylogenetic analysis of asparaginases reveals an increasing group of known sequences of the Rhizobial-type asparaginase II family.