1,959 research outputs found
Dinámica de flujo del Sistema Acuífero Guaraní y sus sistemas acuíferos asociados en su región meridional (Uruguay y Brasil) basada en datos hidroquímicos, isotópicos y de gases nobles
No full textEste informe es una síntesis de los avances en el conocimiento del funcionamiento del Sistema Acuífero Guaraní, realizados por el Dr. Elías Teramoto y el Dr. Hendryx Gemeiner en el marco de sus actividades postdoctorales en el PEDECIBA Geociencias (Universidad de la República – Ministerio de Educación y Cultura).El Sistema Acuífero Guaraní (SAG) es uno de los sistemas acuíferos más grandes del mundo y constituye un recurso hídrico fundamental para Brasil, Argentina, Paraguay y Uruguay. La comprensión de la dinámica del flujo de agua subterránea dentro del SAG es esencial para el desarrollo de modelos conceptuales confiables que respalden su gestión sostenible. Numerosos estudios han analizado las características hidroquímicas e isotópi-cas del SAG, destacando el papel de las interacciones progresivas roca-agua en la evolu-ción hidroquímica del sistema. Sin embargo, algunos aspectos clave aún no se compren-den completamente. Este estudio integra datos hidrogeoquímicos e isotópicos, incluidos iones mayoritarios, isótopos estables y gases nobles disueltos, provenientes de 32 pozos de agua subterránea de la región meridional del SAG, en la región fronteriza entre Brasil y Uruguay. Abarca tanto las secciones confinadas como no confinadas del SAG, así como sus acuíferos suprayacentes del Sistema Acuífero Serra Geral (SASG) e infrayacentes Paleozoicos (Pre-SAG). Además, se realizaron simulaciones geoquímicas para compren-der mejor los procesos de evolución del agua subterránea. Una contribución significativa en este estudio fue la identificación de dos sistemas de flujo divergentes dentro del Sis-tema Acuífero Guaraní (SAG) en el territorio uruguayo. Los resultados revelaron que el SAG está intrincadamente interconectado con el SASG y el Pre-SAG, formando un sis-tema acuífero multicapa caracterizada por un intercambio significativo de agua subterrá-nea entre el SAG y esas unidades acuíferas. Los valores de aire en exceso, expresados como △Ne, fueron relativamente bajos y comparables entre las porciones no confinada y confinada del SAG, con valores de 12,7 ± 9,6 % y 10,7 ± 9,1 %, respectivamente. Las temperaturas promedio de gases nobles (NGT) calculadas indican que las condiciones de recarga han variado en el tiempo, con algunas muestras en el sector confinado del SAG que sugieren una recarga anterior al Último Máximo Glacial (LGM). Además, las signa-turas isotópicas e hidroquímicas, junto con los datos de gases nobles, sugieren una posible mezcla de las aguas subterráneas del SAG con acuíferos adyacentes, lo que desafía los modelos convencionales de circulación del agua subterránea que consideran al SAG como un sistema aislado. Estos hallazgos tienen implicaciones importantes para la gestión del agua subterránea, la modelización numérica del flujo y la estimación de los tiempos de residencia del agua subterránea en la región
Effects of particle size and solid-to-fluid density ratio on the dynamcs of particle-laden homogeneous shear turbulence
No full textParticulate turbulent flows are encountered in many natural and industrial situations. In the present study, we numerically investigate how the dynamics of particle-laden homogeneous shear turbulence depends on the particle size and solid-to-fluid density ratio in order to deepen the understanding of the interaction between particles and turbulent shear flows. We consider the situation where the particle diameter is five to ten times larger than the Kolmogorov scale of turbulence with a solid-to-fluid density ratio between 0.5 and 10. An immersed boundary method is adopted to represent the spherical finite-size particle. Numerical results show that small particles enhance the viscous dissipation inside viscous layers surrounding particles, which leads to the suppression of the growth of homogeneous shear turbulence. The viscous dissipation is further enhanced through the modification of turbulence structure. The enhancement of the viscous dissipation depends strongly on the solid-to-fluid density ratio as well as particle size. In the cases of high density ratio, the generation of vortex tubes is activated around the particles, which leads to the modification of vortex layers and the enhancement of the viscous dissipation
A new method to improve validity range of Lie canonical perturbation theory : with a central focus on a concept of non-blow-up region
No full textValidity ranges of Lie canonical perturbation theory (LCPT) are investigated in terms of non-blow-up regions. We investigate how the validity ranges depend on the perturbation order in two systems, one of which is a simple Hamiltonian system with one degree of freedom and the other is a HCN molecule. Our analysis of the former system indicates that non-blow-up regions become reduced in size as the perturbation order increases. In case of LCPT by Dragt and Finn and that by Deprit, the non-blow-up regions enclose the region inside the separatrix of the Hamiltonian, but it may not be the case for LCPT by Hori. We also analyze how well the actions constructed by these LCPTs approximate the true action of the Hamiltonian in the non-blow-up regions and find that the conventional truncated LCPT does not work over the whole region inside the separatrix, whereas LCPT by Dragt and Finn without truncation does. Our analysis of the latter system indicates that non-blow-up regions do not necessarily cover the whole regions inside the HCN well. We propose a new perturbation method to improve non-blow-up regions and validity ranges inside them. Our method is free from blowing up and retains the same normal form as the conventional LCPT. We demonstrate our method in the two systems and show that the actions constructed by our method have larger validity ranges than those by the conventional and our previous methods proposed in Teramoto and Komatsuzaki (J Chem Phys 129:094302, 2008; Phys Rev E 78:017202, 2008).Published online 13 September 201
Potential diagnostic and prognostic applications of monoclonal antibodies to human mammary carcinomas
No full textA monoclonal antibody (B72.3) defines pattern of distribution of a novel tumor associated antigen in human mammary carcinoma cell population
No full textAuditory object-motion perception during actual self-motion
No full textWe investigated the effect of actual self-motion on auditory object-motion detection. There have been several studies that investigate how eye, head, and whole body movements modulate visual motion processing. However, less is known about their effects on auditory motion processing. Our previous study showed that sounds moving in the congruent directions with visually induced self-motion were detected more quickly and more accurately than those in the conflicting directions, when sounds were presented in rear space (Teramoto et al., 2006 IMRF). In the present study, we used a rotary chair surrounded with random dots and two loudspeakers attached on either the front or the back of the chair, in order to confirm the phenomenon in a more realistic environment. Observers were asked to judge in which direction a sound appeared to move, leftward or rightward, while being rotated around their vertical axis. The results for the rear space condition were consistent with our previous study. On the other hand, those for the front space condition showed that sounds moving in the conflicting directions with self-motion were detected more accurately. The implications of these results are discussed in light of the contribution of the self-motion mechanisms to auditory spatiotemporal processing
Antigenic heterogeneity modulation and evolution in breast cancer lesions as defined by monoclonal antibodies
No full textReactivity of a monoclonal antibody (B72.3) with fixed sections of human mammary carcinomas
No full textMonoclonal antibodies to human mammary carcinoma associated antigens and their potential use for diagnosis,prognosis and therapy
No full textPotential of monoclonal antibody technology in the management of human mammary carcinoma
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