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The quantum states of a cylindrical quantum dot (CDQ) of GaAs/Ga0.6Al0.4As are studied theoretically with a hydrogen-like impurity inside and under the action of a uniform magnetic field, applied in the axial direction of the cylinder. Using the variational method, the energies and wave functions of the impurity states, 1s-like, 2p−-like and 2p+-like, when she moves inside the CQD. It was found that there is degeneracy in the impurity energy for the 2p−-like and 2p+-like states in the absence of a magnetic field. This degeneracy is broken only by applying a magnetic field, indicating a Zeeman effect in the system, thus, the variation of the intensity of the magnetic field allows to tune the resonance condition of two photons. [ABSTRACT FROM AUTHOR]

The effect of aluminum concentration on the second harmonic generation (SHG) in a cylindrical quantum dot (CQD) is studied theoretically, using the density matrix formalism and a perturbative procedure. The energy levels and wave functions of an electron in the CQD were obtained by solving the time-independent Schrödinger equation in the framework of the effective mass approximation. Numerical calculations are performed for a CQD of GαAs/Al1-xGaxAs. It was found that the increase in the aluminum concentration produces a decrease in the intensity of the SHG and a blue shift in the resonant peaks of the optical response of the object of study. [ABSTRACT FROM AUTHOR]

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Starting from a structure composed of two conical quantum dots (CQDs) vertically coupled of GaAs surrounded by AlxGa1-xAs at a concentration of 0.3, it is first studied how the dimensions of the system cause a change in the confinement, for this the height of the upper quantum well and the optimal one is found to work with, with this defined, the effects of hydrostatic pressure (between 0 GPa and 3 GPa) and temperature (between 0 K and 300 K) on the effective mass, the width band gap (Gap), the dielectric constant and its impact on the self-energies and selffunctions of the system. In addition, the effects of including the presence of an impurity in the structure located in the lower quantum well will be evaluated. Making use of the finite element method, variations in the energies and wave functions of the system are evidenced, which are due to changes of the effective mass and the new potential energy. Analyzing the behavior of the binding energy, a change in the dielectric constant is noted when the system is subjected to a temperature around 200 K, since above this value the Gap changes from being direct to being indirect. Finally, the presence of the impurity in the system generates an additional potential, consequently, the energies in the structure decrease under the evaluated effects, making more forceful changes in the wave functions and energies due to this potential. [ABSTRACT FROM AUTHOR]

The Nobel Prize in Chemistry 2023 has been awarded to Moungi G. Bawendi, Louis E. Brus, and Alexei I. Ekimov for the discovery and synthesis of quantum dots. Quantum dots are semiconductor materials structured on the nanoscale that exhibit variable electronic and optical properties depending on their size. The discoveries and synthesis of quantum dots have been fundamental for the study of nanocrystals and their application in various fields. Additionally, the applications of nanocrystals in optoelectronic devices and television screens are mentioned, as well as their use in species detection in solution, photocatalysis, quantum information processing, and nanomedicine. The article concludes that the discovery of the relationship between optical properties and size in semiconductor nanocrystals has opened up many possibilities for study and practical application. [Extracted from the article]

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A theoretical study on the nonlinear optical rectification in a cylindrical quantum dot (CQD) in the presence of a uniform magnetic field by using the density matrix formalism and a perturbation method is presented. The energy levels and wave functions of an electron in the CQD were obtained by solving the timeindependent Schrödinger equation within the effective mass approximation. Numerical calculations are performed for a CQD of the type GaAs/AlGaAs. It was found that the increase in the dimensions of CQD and/or the magnetic field intensity cause an increase on the resonance peak intensity and a shift to lower energies regions (red shift). The physical reason for this behavior is attributed to the quantum confinement effect generated by the variation of the magnetic field strength and of the size of the nanostructure. [ABSTRACT FROM AUTHOR]

In order to evaluate dot blot tests and latex agglutination for the detection of human cysticercosis with liquid antigen of Taenia solium cysticerci, 125 human sera were used, of which 60 were from people with cysticercosis confirmed by Western Blot, 45 with other parasitic diseases and 20 apparently healthy. The optimal concentration of antigen to impregnate dot blot strips was 0.01 ug/uL, and to impregnate the latex particles was 0.092 ug/uL. For the dot blot test, a sensitivity of 100% and specificity of 87.7% was found. For latex agglutination, a sensitivity of 93.3% and specificity of 89.2% was found. Both tests may be useful and feasible to implement alternatives of serological diagnosis in laboratories in endemic areas of Peru. [ABSTRACT FROM AUTHOR]

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We study the electronic transport through a quantum wire (QW), described by a tight-binding chain, with an embedded quantum dot (QD). We obtain the conductance with a strong Fano resonance; the density of states shows that this behavior is linked to a many-body renormalized QD resonant level &Etilde;f at the edge of the conduction band (CB), strongly hibridized with the Van Hove peaks of the one dimensional density of states for the lead. The obtained Fano resonance is thermically activated, above the Kondo temperature; this is due to the quantum interference between the CB and a thermal activated channel created by the QD resonance at the vicinity of the bottom of the CB. Our results are in qualitative agreement with those reported for a T-coupled QD. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Alergia de Mexico is the property of Coleg. Mexicano de Inmunologia Clinica y Alergia A.C.; Soc. Lat. de Alergia, Asma e Inmunologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Momento: Revista de Física is the property of Universidad Nacional de Colombia, Departamento de Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Dilemas Contemporáneos: Educación, Política y Valores is the property of Dilemas Contemporaneos: Educacion, Politica y Valores and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The bacterial wilt, caused by Ralstonia solanacearum, affects various economically important crops. A successful disease management depends on the precise and early diagnostic. The objective of the present work was to optimize the serologic methods to detect R. solanacearum. Antibody polyclonal was obtained for being used in the serological techniques. The sensitivity and specificity of methods were determined. The detection limit was from 104 to 106 CFU/mL detected in plant extracts and tubercles by ultramicroanalytic system, ELISA, DOT-BLOT, latex agglutination and immunofluorescence. When the sample was first incubated in SMSA broth prior testing, the sensitivity of pathogen detection used was as low as 10² CFU/ml. R. solanacearum isolates belonging to biovars 1 and 2 were successfully detected with this technique. No cross-reactions was obtained with other genera and bacteria species studied. The analytical parameters to serology tests were estimated above 90%. [ABSTRACT FROM AUTHOR]

Copyright of Revista Signos is the property of Pontificia Universidad Catolica de Valparaiso and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective. To determine the ability of cigarette-pack warning labels, of the minimum size required by the World Health Organization, to capture the attention of smokers and nonsmokers. Methods. In this study, 30 smokers and 30 nonsmokers completed a dot-probe task in which they simultaneously observed images of cigarette packs split in two: the top contained the cigarette brand and the bottom contained the warning label. During the task, brain activity was recorded through two event-related potentials of the negative-polarity type-the potential that occurs in the posterior-contralateral zone approximately 200 ms after a stimulus (N2pc) and the sustained posterior contralateral negativity (SPCN) response-which are indicators of early and sustained attention. Results. In both groups, a greater amplitude of N2pc and SPCN potentials was found for the part of the pack containing the cigarette brand. However, during the dot-probe task, reaction times were shorter for the warning label. Conclusions. These results suggest that, initially, attention is focused on the cigarette brand, and only then on the warning label. The inability of warning labels to capture early-phase attention decreases their effectiveness, especially in smokers. We suggest that warning labels be enlarged to facilitate increased attention response. [ABSTRACT FROM AUTHOR]