https://repositorio.uoh.cl/handle/611/19 2026-04-07T05:41:26Z 2026-04-07T05:41:26Z Flores Chacón, Raúl https://repositorio.uoh.cl/handle/611/1100 2026-01-12T18:09:20Z 2025-01-01T00:00:00Z

Respuesta metabolómica en raíces de portainjertos contrastantes de Lagenaria siceraria y hojas del injerto Citrullus lanatus bajo condiciones de estrés por sequía Flores Chacón, Raúl La sandía (Citrullus lanatus) requiere altos volúmenes de agua para alcanzar un adecuado llenado de frutos, lo que hace crítico el estudio del déficit hídrico en su cultivo. Una estrategia efectiva para enfrentar este problema es el uso de portainjertos tolerantes como Lagenaria siceraria, conocidos por sus características morfofisiologícas que favorecen la resistencia al estrés por sequía, además del uso de riego deficitario, para así aplicar la cantidad mínima de riego que necesita el cultivo sin dañar su producción. Este estudio analizó el perfil metabolómico de raíces e injertos en plantas injertadas sobre dos accesiones de L. siceraria (Illapel y Philippines) y un homoinjerto de C. lanatus, bajo condiciones de riego completo y estrés hídrico. Los resultados revelaron una acumulación diferencial de metabolitos en hojas de C. lanatus injertadas sobre Illapel, identificando 16 metabolitos compartidos entre ambos tejidos, asociados principalmente a mecanismos de defensa frente al estrés abiótico. Además, el análisis de enriquecimiento funcional evidenció la activación de rutas metabólicas relacionadas con la osmorregulación, el balance redox y el metabolismo energético, destacando el papel del injerto en la adaptación de la planta al déficit hídrico. Citrullus lanatus, sequía, riego deficitario, Lagenaria siceraria, metabolitos, producción.

2025-01-01T00:00:00Z Alarcón, H Galaz, B Espíndola, D https://repositorio.uoh.cl/handle/611/513 2024-04-17T13:45:56Z 2024-01-01T00:00:00Z

Experimental observations of Scholte waves propagating in an incompressible soft solid Alarcón, H; Galaz, B; Espíndola, D Due to the heterogeneous structure of the soft biological tissue, such as the brain, surface waves might be important to elucidate the biomechanics of injury formation from impacts. In this context, surface waves generate a wavelength on the order of the centimeter with a typical penetration length of the same order. Therefore, investigating surface waves at depth is crucial for understanding their relationship with the physics of soft tissue injuries. Planar surface waves produce particle motion along two dimensions, the direction of propagation and the depth direction, making them more challenging to measure when compared to polarized shear waves that only produce motion in one direction. This study presents an experimental setup capable of generating Scholte wave propagating in a soft solid-liquid interface. In particular, we studied a tissue-mimicking phantom material, such as gelatin, under a layer of water. Ultrasound imaging techniques, operating at 8600 frames per second, and a one-dimensional cross-correlation algorithm were used to independently estimate the two components of the wave's particle displacement. We conducted experiments sweeping frequencies between 50 and 500 Hz for different gelatin stiffness, finding a surface wave speed of 0.86 times the shear wave speed and a penetration distance of 0.35 times the wavelength. These results agree with the theory of Scholte waves propagating in an incompressible semi-infinite elastic medium covered by an incompressible fluid.

2024-01-01T00:00:00Z Soto, MV Sarricolea, P Sepúlveda, SA Rodolfi, G Cabello, M Maerker, M https://repositorio.uoh.cl/handle/611/338 2024-04-16T19:13:07Z 2017-01-01T00:00:00Z

Assessment of hydro-geomorphological hazard potentials in the Chilean semiarid coastal range and its impacts on La Serena city, Coquimbo Region Soto, MV; Sarricolea, P; Sepúlveda, SA; Rodolfi, G; Cabello, M; Maerker, M Two micro-catchments, tributaries of the Elqui River in the coastal range of the semiarid central-northern Chile were analyzed to establish the hazard potentials associated with extreme rainfall and their effects on the urban area of La Serena city. Geomorphological mapping was performed identifying the morphological features associated with inherited and present-day processes, through photointerpretation and field work. To assess the geohazard potentials related to extreme precipitation events, a detailed terrain analysis was performed deriving topographic indices that in turn characterize the related process potentials. Extreme rainfall events were calculated with a decadal recurrence ([ 60 mm/day) and are subsequently associated with El Nino (ENSO) and Pacific Decadal Oscillation (PDO warm phase) events. We applied a simple storm flow model using a 20-year return period reflecting a disastrous flood event that affected the La Serena urban area in June 2011. The results highlight the spatial distribution of the hazard potentials in the two Elqui tributaries and their effects on the La Serena urban area. We show that areas subject to intensive land use change and urban sprawl associated with the lower marine terrace and river mouth of the Elqui River are of very high flooding and tsunami risk.

2017-01-01T00:00:00Z Sun, T. Álvarez-Novoa, F. Andrade, K. Gutiérrez, P. Gordillo, L. Cheng, X. https://repositorio.uoh.cl/handle/611/27 2022-10-20T18:00:42Z 2022-01-01T00:00:00Z

Stress distribution and surface shock wave of drop impact Sun, T.; Álvarez-Novoa, F.; Andrade, K.; Gutiérrez, P.; Gordillo, L.; Cheng, X. Drop impact causes severe surface erosion, dictating many important natural, environmental and engineering processes and calling for substantial prevention and preservation efforts. Nevertheless, despite extensive studies on the kinematic features of impacting drops over the last two decades, the dynamic process that leads to the drop-impact erosion is still far from clear. Here, we develop a method of high-speed stress microscopy, which measures the key dynamic properties of drop impact responsible for erosion, i.e., the shear stress and pressure distributions of impacting drops, with unprecedented spatiotemporal resolutions. Our experiments reveal the fast propagation of self-similar noncentral stress maxima underneath impacting drops and quantify the shear force on impacted substrates. Moreover, we examine the deformation of elastic substrates under impact and uncover impact-induced surface shock waves. Our study opens the door for quantitative measurements of the impact stress of liquid drops and sheds light on the origin of low-speed drop-impact erosion.

2022-01-01T00:00:00Z