Studies on the Contact Sensitization of Man with Simple Chemicals

Dinitrochlorobenzene (DNCB) coupled to peripheral blood erythrocytes or leukocytes forms a particulate complex, DNCB-antigen. The addition of DNCB-antigen induced blastogenesis and DNA synthesis in leukocyte cultures from DNCB-sensitized human subjects and not in leukocyte cultures from nonsensitized controls. In general, sensitized subjects who displayed a higher degree of cutaneous reactivity to DNCB, as manifested by duration and intensity of dermatitis, also showed a greater blastogenic response to DNCB-antigen in vitro. This quantitative correlation, however, was not invariant. Certain soluble factor(s), or lymphokines are released following the addition of DNCB-antigen to leukocyte cultures prepared from some sensitive subjects who were rechallenged one or more times with DNCB. These lymphokines induce blastogenesis in secondary target leukocyte populations from nonsensitized subjects. Extended studies are presented which show little or no lymphokine activity in peripheral blood leukocyte cultures during a primary immune response, despite high degrees of blastogenic activity in response to DNCB-antigen. Significant lymphokine activity was observed only following additional rechallenge with DNCB.Blastogenesis and skin reactivity specific for DNCB have been shown to develop at about the same time during a primary immune response. This, along with the quantitative correlation shown in this communication, suggests that both processes probably reflect thymic-dependent cellular immunity. The appearance of lymphokine activity following rechallenge with DNCB suggests that DNCB-induced lymphokines may represent an amplifying mechanism of the cellular immune response that involves recruitment of previously uncommitted lymphocytes

Beable trajectories for revealing quantum control mechanisms

The dynamics induced while controlling quantum systems by optimally shaped laser pulses have often been difficult to understand in detail. A method is presented for quantifying the importance of specific sequences of quantum transitions involved in the control process. The method is based on a ``beable'' formulation of quantum mechanics due to John Bell that rigorously maps the quantum evolution onto an ensemble of stochastic trajectories over a classical state space. Detailed mechanism identification is illustrated with a model 7-level system. A general procedure is presented to extract mechanism information directly from closed-loop control experiments. Application to simulated experimental data for the model system proves robust with up to 25% noise.Comment: Latex, 20 pages, 13 figure

The relationship of readiness factors to Jan. first grade reading achievement

Thesis (Ed.M.)--Boston Universit

Dynamics and hysteresis in square lattice artificial spin-ice

Dynamical effects under geometrical frustration are considered in a model for artificial spin ice on a square lattice in two dimensions. Each island of the spin ice has a three-component Heisenberg-like dipole moment subject to shape anisotropies that influence its direction. The model has real dynamics, including rotation of the magnetic degrees of freedom, going beyond the Ising-type models of spin ice. The dynamics is studied using a Langevin equation solved via a second order Heun algorithm. Thermodynamic properties such as the specific heat are presented for different couplings. A peak in specific heat is related to a type of melting-like phase transition present in the model. Hysteresis in an applied magnetic field is calculated for model parameters where the system is able to reach thermodynamic equilibrium.Comment: Revised versio

Natural hosts of different hantavirus genotypes in south America: who is who?

Gardenal, C.N., Gonzalez-Ittig, R.E., Rivera, P.C., Levis, S., Salazar-Bravo, J., Barquez, R.M

Variabilidad infrarroja del núcleo activo en NGC 2992

There are galaxies in the Universe that harbour an active nucleus and present variability in the type of emission, varying in their Seyfert type classification, and in their nuclear magnitude. In this work, a photometric study of the galaxy NGC 2992 is presented. In the latest decades, this galaxy has gone through episodes of variability in the optical, infrared, and X-ray ranges. In this contribution, nuclear magnitudes in J band are reported from observations carried on in January 2022 and the magnitude obtained in a 3" aperture is compared with previous reports, finding a variation of 0.8±0.3 magnitudes with respect to 1998.Hay galaxias en el Universo que albergan un núcleo activo y presentan variabilidad en el tipo de emisión, variando en su clasificación tipo Seyfert, y en su magnitud nuclear. En este trabajo se presenta un estudio fotométrico de la galaxia NGC 2992. En las últimas décadas, esta galaxia ha atravesado episodios de variabilidad en los rangos óptico, infrarrojo y de rayos X. En esta contribución se reportan magnitudes nucleares en la banda J a partir de observaciones realizadas en enero de 2022 y se compara la magnitud obtenida en una apertura de 3" con informes anteriores, encontrando una variación de 0,8±0,3 magnitudes con respecto a 1998.Fil: Levis, Selene. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Gaspar, G.. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Diaz, Carlos Gonzalo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mast, D.. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Diaz, R. J.. Gemini Observatory; Estados Unido

Space-time coupling of shaped ultrafast ultraviolet pulses from an acousto-optic programmable dispersive filter

A comprehensive experimental analysis of spatio-temporal coupling effects inherent to the acousto-optic programmable dispersive filter (AOPDF) is presented. Phase and amplitude measurements of the AOPDF transfer function are performed using spatially and spectrally resolved interferometry. Spatio-temporal and spatio-spectral coupling effects are presented for a range of shaped pulses that are commonly used in quantum control experiments. These effects are shown to be attributable to a single mechanism: a group-delay--dependent displacement of the shaped pulse. The physical mechanism is explained and excellent quantitative agreement between the measured and calculated coupling speed is obtained. The implications for quantum control experiments are discussed.Comment: 8 pages, 6 figures; accepted for publication within JOSA