Instituto Politécnico Nacional

About: Instituto Politécnico Nacional is a education organization based out in Mexico City, Mexico. It is known for research contribution in the topics: Population & Control theory. The organization has 43351 authors who have published 63315 publications receiving 938532 citations. The organization is also known as: Instituto Politécnico Nacional & Instituto Politecnico Nacional.

Vibrios associated with Litopenaeus vannamei larvae, postlarvae, broodstock, and hatchery probionts.

Abstract: Several bacteriological surveys were performed from 1994 to 1996 at different Litopenaeus vannamei hatcheries (in Ecuador) and shrimp farms (in Mexico). Samples were taken from routine productions of healthy and diseased L. vannamei larvae, postlarvae, and their culture environment and from healthy and diseased juveniles and broodstock. In Ecuador, the dominant bacterial flora associated with shrimp larvae showing symptoms of zoea 2 syndrome, mysis mold syndrome, and bolitas syndrome has been determined. Strains were characterized by Biolog metabolic fingerprinting and identified by comparison to a database of 850 Vibrio type and reference strains. A selection of strains was further genotypically fine typed by AFLP. Vibrio alginolyticus is predominantly present in all larval stages and is associated with healthy nauplius and zoea stages. AFLP genetic fingerprinting shows high genetic heterogeneity among V. alginolyticus strains, and the results suggest that putative probiotic and pathogenic strains each have specific genotypes. V. alginolyticus was found to be associated with larvae with the zoea 2 syndrome and the mysis mold syndrome, while different Vibrio species (V. alginolyticus and V. harveyi) are associated with the bolitas syndrome. V. harveyi is associated with diseased postlarvae, juveniles, and broodstock. The identities of the strains identified as V. harveyi by the Biolog system could not be unambiguously confirmed by AFLP genomic fingerprinting. Vibrio strain STD3-988 and one unidentified strain (STD3-959) are suspected pathogens of only juvenile and adult stages. V. parahaemolyticus, Photobacterium damselae, and V. mimicus are associated with juvenile and adult stages.

Search for narrow and broad dijet resonances in proton-proton collisions at √s=13 TeV and constraints on dark matter mediators and other new particles

Abstract: Searches for resonances decaying into pairs of jets are performed using proton-proton collision data collected at s√=13 TeV corresponding to an integrated luminosity of up to 36 fb−1. A low-mass search, for resonances with masses between 0.6 and 1.6 TeV, is performed based on events with dijets reconstructed at the trigger level from calorimeter information. A high-mass search, for resonances with masses above 1.6 TeV, is performed using dijets reconstructed offline with a particle-flow algorithm. The dijet mass spectrum is well described by a smooth parameterization and no evidence for the production of new particles is observed. Upper limits at 95% confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.7 TeV, scalar diquarks below 7.2 TeV, axigluons and colorons below 6.1 TeV, excited quarks below 6.0 TeV, color-octet scalars below 3.4 TeV, W′ bosons below 3.3 TeV, Z′ bosons below 2.7 TeV, Randall-Sundrum gravitons below 1.8 TeV and in the range 1.9 to 2.5 TeV, and dark matter mediators below 2.6 TeV. The limits on both vector and axial-vector mediators, in a simplified model of interactions between quarks and dark matter particles, are presented as functions of dark matter particle mass and coupling to quarks. Searches are also presented for broad resonances, including for the first time spin-1 resonances with intrinsic widths as large as 30% of the resonance mass. The broad resonance search improves and extends the exclusions of a dark matter mediator to larger values of its mass and coupling to quarks.

Urban traffic control structure based on hybrid Petri nets

Abstract: An urban network of signalized intersections can be suitably modeled as a hybrid system, in which the vehicle flow behavior is described by means of a time-driven model and the traffic light dynamics are represented by a discrete event model. In this paper, a model of such a network via hybrid Petri nets is used to state and solve the problem of coordinating several traffic lights with the aim of improving the performance of some classes of special vehicles, i.e., public and emergency vehicles. The proposed model has been validated using real traffic data relevant to the city of Torino, Italy. Some relevant experimental results are reported and discussed.

An Approach to Understanding the Electrocatalytic Activity Enhancement by Superexchange Interaction toward OER in Alkaline Media of Ni–Fe LDH

Abstract: In the present work, the hydrotalcite-like materials known as layered double hydroxides (LDHs) were synthesized. The Ni–Al and Ni–Fe materials with different Ni/Fe ratio were obtained by coprecipitation method at variable pH. The LDH structure was verified by X-ray diffraction, Fourier transform infrared, and Raman spectroscopy. No secondary extra phases were observed for any material. The electronic properties were evaluated by UV–vis spectroscopy, while the magnetic ones were followed by electron paramagnetic resonance (EPR). The results suggested that sample H/Ni–Fe2 (Ni/Fe = 2) has a ferrimagnetic behavior as a result of the combined action of NiII–OH–NiII, FeIII–OH–NiII, and FeIII–OH–FeIII pairs across the layers and ferromagnetic interactions operating between layers. Furthermore, the material H/Ni–Fe1 (Ni/Fe = 1.5) showed a combination of paramagnetic and ferromagnetic interactions which favors a superexchange interaction among metal centers through the OH bridges across the cationic sheets; the su...