Karst springs

Los manantiales kársticos son los puntos de salida del agua que circula y está almacenada en los acuíferos kársticos. La descarga de estos manantiales puede variar muchísimo, desde pequeños rezumes a caudales de varias decenas de metros cúbicos por segundo, capaces de originar ríos. A lo largo de la historia, los manantiales kársticos han sido determinantes a la hora de establecer asentamientos humanos y son numerosos los pueblos y ciudades que se abastecen de sus aguas, generalmente de excelente calidad. El comportamiento de los acuíferos kársticos difiere en gran medida de otros tipos de acuíferos y sus manantiales presentan ciertas singularidades. El presente trabajo pretende mostrar algunos de estos aspectos a partir de ejemplos de varios manantiales de la geografía española.Karst springs are the outlets of the water that flows and is stored in karstic aquifers. The discharge of these springs can vary greatly, from small leakages virtually unnoticed to flow rates of several tens of cubic meters capable of originating rivers. Throughout history, karst springs have been determining factors when establishing settlements and there are numerous towns and cities supplied by those spring waters, generally of an excellent quality. The behavior of karst aquifers differs greatly from other types of aquifers and their springs have special features. This paper aims to show some of these features from several springs of the Spanish geography

3D VMAT Verification Based on Monte Carlo Log File Simulation with Experimental Feedback from Film Dosimetry.

A model based on a specific phantom, called QuAArC, has been designed for the evaluation of planning and verification systems of complex radiotherapy treatments, such as volumetric modulated arc therapy (VMAT). This model uses the high accuracy provided by the Monte Carlo (MC) simulation of log files and allows the experimental feedback from the high spatial resolution of films hosted in QuAArC. This cylindrical phantom was specifically designed to host films rolled at different radial distances able to take into account the entrance fluence and the 3D dose distribution. Ionization chamber measurements are also included in the feedback process for absolute dose considerations. In this way, automated MC simulation of treatment log files is implemented to calculate the actual delivery geometries, while the monitor units are experimentally adjusted to reconstruct the dose-volume histogram (DVH) on the patient CT. Prostate and head and neck clinical cases, previously planned with Monaco and Pinnacle treatment planning systems and verified with two different commercial systems (Delta4 and COMPASS), were selected in order to test operational feasibility of the proposed model. The proper operation of the feedback procedure was proved through the achieved high agreement between reconstructed dose distributions and the film measure- ments (global gamma passing rates > 90% for the 2%/2 mm criteria). The necessary discre- tization level of the log file for dose calculation and the potential mismatching between calculated control points and detection grid in the verification process were discussed. Besides the effect of dose calculation accuracy of the analytic algorithm implemented in treatment planning systems for a dynamic technique, it was discussed the importance of the detection density level and its location in VMAT specific phantom to obtain a more reliable DVH in the patient CT. The proposed model also showed enough robustness and efficiency to be considered as a pre-treatment VMAT verification system.Ministerio de Ciencia y Tecnología SAF2011- 27116; IPT-2011-1480-900000

Proyecto de difusión y promoción del nuevo Grado en Geología

Memoria ID-0226. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2014-2015

Comprehensive characterization of Gunn oscillations in In0.53Ga0.47As planar diodes

[EN]In this work, In0.53Ga0.47As planar Gunn diodes specifically designed for providing oscillations at frequencies below 30 GHz have been fabricated and characterized. Different types of measurements were used to define a set of consistent methods for the characterization of the oscillations that can be extended to the sub-THz frequency range. First, negative differential resistance and a current drop are found in the I–V curve, indicating the potential presence of Gunn oscillations (GOs), which is then confirmed by means of a vector network analyzer, used to measure both the S11 parameter and the noise power density. The onset of unstable GOs at applied voltages where the negative differential resistance is hardly visible in the I–V curve is evidenced by the observation of a noise bump at very low frequency for the same applied voltage range. Subsequently, the formation of stable oscillations with an almost constant frequency of 8.8 GHz is observed for voltages beyond the current drop. These results have been corroborated by measurements performed with a spectrum analyzer, which are fully consistent with the findings achieved by the other techniques, all of them applicable to Gunn diodes oscillating at much higher frequencies, even above 300 GHz.Spanish MINECO through project TEC2017-83910-R and the Junta de Castilla y León and FEDER through projects SA022U16 and SA254P18

Elaboración del curso “Laboratorio de Termodinámica” en la plataforma iTunes U de la Universidad de Salamanca

Memoria ID-0119. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2013-2014

Impact of the COVID-19 Pandemic on the Evolution of Prevalence and Patterns of Cannabis Use among First-Year University Students in Spain—UniHcos Project

Among university students there has been evidence that the COVID-19 pandemic increased their psychological distress, exacerbated by social restrictions. The main objective of this study was to explore the impact of the COVID-19 pandemic on the prevalence and patterns of cannabis use among university students, in contrast to previous trends since 2012. Data from 10,522 first-year university students (73.3% female, Mage 19 (SD = 1.6)) from eleven Spanish universities collected between 2012 and May 2022 was analysed. Prevalences of cannabis use and their differences by sex were studied, as well as changes in patterns of use and its use for coping during the pandemic. It was found that during lockdown, all prevalence rates of cannabis use decreased in both sexes, showing no statistically significant differences and increasing again in the new normal period in both. Among regular cannabis users, 79.7% reported maintaining or increasing their cannabis use during the pandemic, and of these, half reported using cannabis to cope. Moreover, cannabis use in the usual household increased during the lockdown. These results show that although the overall prevalence of cannabis use was reduced during the lockdown, regular users tended to maintain or increase cannabis use. This could imply two different patterns of use among students, one social and occasional versus the other regular, providing new lines of research for prevention and the implementation of social policies.This research was funded by the National Drug Plan from the Ministry of Health, Social Services and Equality of Spain (Grant numbers: 2010|145, 2013|034 and 2020|030) and Instituto de Salud Carlos III (Grant number: PI16/01947)

Analysis of autophagy gene polymorphisms in Spanish patients with head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth cancer on incidence worldwide. Tobacco and alcohol consumption are the most classical risk factors associated with its development. Autophagy process has a dual effect both in tumourigenesis and tumour suppressing activity. To investigate the importance of this pathway in HNSCC susceptibility, a risk factor matched case-control association study was performed with four candidate polymorphisms in autophagy genes (ATG2B, ATG5, ATG10, ATG16L1). We found an association between the variant in ATG10 rs1864183 and a higher susceptibility to develop laryngeal cancer, ATG2B rs3759601 and pharyngeal cancer and ATG16L1 rs2241880 and oral carcinoma. ATG5 rs2245214 SNP was not associated with any location. Overall, our results indicate the importance of the autophagy pathway in the susceptibility of head and neck squamous cell carcinoma and demonstrate the heterogeneity between its locations encompassed under a single terminology

The role of CCR5/CXCR3 expressing CD8+ cells in liver damage and viral control during persistent hepatitis C virus infection

20 p.Background/Aims:CXCR3 and CCR5 play a major role in recruiting cytotoxic T cells (Tc) and secreting secondary type 1 cytokines (Tc1) in the liver. HCV could impair their expression as a survival mechanism. The role of these chemokine receptors on CD8+ cells in chronic hepatitis C is analysed. Methods:Serum, chemokines, peripheral blood and intrahepatic lymphocytes from chronic hepatitis C patients were studied. CXCR3 / CCR5 expressing CD8+ cells were quantified by flow-cytometry. Serum chemokines concentration (CXCL10/CCL3) was measured by ELISA. Basal data were correlated with liver inflammation. Longitudinal data were obtained during treatment and correlated with virologic response. Results:CCR5/CXCR3 expressing CD8+ cells were enriched in the liver and correlated with inflammation. Chronic HCV patients presented the same frequency of CCR5high/CXCR3high expressing CD8+ cells in peripheral blood as in healthy controls but higher serum concentration of CXCL10/CCL3. Treatment with PEG-interferon a-2b plus ribavirin increased CCR5high/CXCR3high expressing CD8+ cells frequency in peripheral blood and decreased CXCL10/CCL3 serum concentration. Increase in CXCR3high expressing CD8+ cells after 24 weeks of treatment was correlated with SVR. Conclusions:In chronic hepatitis C, anti-viral treatment induces an increase in CD8+ cells expressing chemokine receptors associated with Tc1 response and a reduction in their ligands. Achievement of viral control is associated with an increase in CXCR3high expressing CD8+ cells during treatmentSchering-Plough-SpainJunta de Comunidades de Castilla-La Manch