Ensenada Center for Scientific Research and Higher Education

About: Ensenada Center for Scientific Research and Higher Education is a facility organization based out in Ensenada, Mexico. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 1934 authors who have published 3733 publications receiving 63115 citations.

Schinus molle L. essential oil-loaded chitosan nanoparticles: Preparation, characterization, antifungal and anti-aflatoxigenic properties

Abstract: Essential oils (EO) have been studied as a possible substitute of fungicides. EO have been loaded in polymeric nanoparticles to prevent their degradation and enhance antifungal activity. In this work was to prepared chitosan nanoparticles with Schinus molle EO by ionotropic gelation. The bionanocomposites were characterized by scanning electronic microscopy (SEM), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FTIR). The antifungal activity was evaluated in different growth stages of A. parasiticus (spore germination, radial growth and spore viability) and the effect in aflatoxin production was analyzed by using affinity chromatography columns from VICAM. DLS results showed that the Np-CS and Np-CS-SEO diameters were 361.9 ± 31.4 and 516.9 ± 45.4 nm, respectively. According to SEM, the NPs presented spherical shape and the zeta potential was slightly decreased when Schinus molle EO was incorporated. The Np-CS-SEO (62.5–500 μg mL−1) showed a high inhibition (>80%) on spore germination of A. parasiticus at 12 h of incubation, while, radial growth was not inhibited for these NPs. At a concentration of 500 μg mL−1, Np-CS-SEO inhibited up to 59% the aflatoxin production. Depending on concentration, the Np-CS-SEO can be considered as an alternative to control A. parasiticus.

Adaptive identification of linear time‐delay systems

Abstract: Synthesis of an adaptive parameter identifier is developed for linear dynamic systems with finitely many lumped delays in the state vector and control input. These systems are governed by linear functional differential equations with uncertain time-invariant parameters and delays. The state of the system is assumed to be available for measurements. Constructive necessary and sufficient conditions for the system parameters and delays to be identifiable are provided. Once the parameter identifiability is guaranteed the simultaneous on-line identification of the system parameters and delays is achieved by the adaptive identifier proposed. Theoretical results are supported by numerical simulation. Copyright © 2003 John Wiley & Sons, Ltd.

The Aljibes half-graben—Active extension at the boundary between the trans-Mexican volcanic belt and the Basin and Range Province, Mexico

Abstract: The Aljibes half-graben is located 140 km west-northwest of Mexico City and is characterized by several parallel, ≥10-km-long, south-dipping, and east-striking normal faults. Late Miocene basalt flows with 40 Ar/ 39 Ar ages of 7.7 ± 0.1 Ma and 7.1 ± 0.5 Ma are displaced along these faults. With reference to this basalt, the composite throw and heave of the half-graben are 480 m and 270 m, respectively, and the relative extension is 5%, whereas the vertical slip rate along the faults of the Aljibes half-graben after the deposition of the basalt is ≥0.07 mm/yr. The Aljibes half-graben is located at the northern margin of the trans-Mexican volcanic belt and perpendicularly intersects northstriking normal faults of the Basin and Range Province. The relative sequence of activity of the two stress fields and fault systems cannot be resolved in the study area, and the two systems may have been active simultaneously. We explain this structural configuration by horizontal migration of the boundary between the two stress provinces with time, which requires intermittent permutations between the intermediate and least principal stresses σ 2 and σ 3 . This is supported by the low-stress ratio Φ = (σ 2 − σ 3 /(σ 1 − σ 3 ) obtained from modeling the stress tensor associated with the slip along the faults of the Aljibes half-graben. The orientations of the fault planes and slip vectors of the Aljibes half-graben are practically identical to those of the nearby Acambay graben and the Venta de Bravo fault, which caused the Acambay earthquake of November 19, 1912 (M S = 6.9), and the Maravatio earthquake of February 22, 1979 (m b = 5.3). Furthermore, the Aljibes half-graben forms the extrapolated western continuation of the northern master fault of the Mezquital graben, which ruptured partly in the Cardonal earthquake of March 26, 1976 (m b = 5.3). This suggests the Aljibes half-graben may also be seismically active, although no historical earthquake is known to have occurred along this structure. Further evidence for the likely seismic activity of the Aljibes half-graben are two east- to eastnortheast–trending epicenter alignments between the Aljibes halfgraben and the Mezquital graben, and structural indication for stickslip behavior. Based on the structure of the Aljibes half-graben, we believe the maximum credible earthquake that may occur along the faults of the Aljibes half-graben is on the order of 2 × 10 27 dyne cm ≥ M 0 ≥ 6 × 10 25 dyne cm and 7.5 ≥ M w ≥ 6.5.