316 research outputs found

    Classical ladder functions for Rosen-Morse and curved Kepler-Coulomb systems

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    Producción CientíficaLadder functions in classical mechanics are defined in a similar way as ladder operators in the context of quantum mechanics. In the present paper, we develop a new method for obtaining ladder functions of one dimensional systems by means of a product of two ‘factor functions’. We apply this method to the curved Kepler–Coulomb and Rosen–Morse II systems whose ladder functions were not found yet. The ladder functions here obtained are applied to get the motion of the systems.Ministerio de Economía, Industria y Competitividad (project MTM2014-57129-C2-1-P)Junta de Castilla y León-FEDER (projects BU229P18 / VA057U16 / VA137G18)

    Estudio de los impactos ambientales de los cruces de gasoductos con ríos vadeables

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    El río Cigüela y su afluente Valdepineda (Cuenca, España) fueron afectados por el cruce de un gasoducto, en Diciembre de 2001, mediante la técnica convencional "cruce subálveo" que consta de tres fases: instalación de la pista de trabajo, apertura de zanja y rehabilitación. Con el objetivo de evaluar el impacto de las distintas etapas de la obra en el medio acuático, se está llevando a cabo un estudio que se centra en el efecto de los sólidos en suspensión en las comunidades macrobentónicas e ícticas. Se presentan los resultados preliminares obtenidos en la fase de apertura de zanja, donde se observa un valor muy elevado de movilización de sólidos en suspensión (hasta 5000 mg/l), alcanzando las mayores concentraciones en los 100 primeros metros aguas abajo del punto de cruce. Estos sólidos en suspensión podrían ser la causa del aumento significativo de la sedimentación de las partículas de tamaño comprendido entre 50-250 μm y 250-500 μm en los 30 primeros metros aguas abajo del punto de cruce. Por otro lado, no se han observado diferencias en el valor del índice BMWP' en las distintas estaciones de muestreo. Sin embargo, en la fase de rehabilitación, se encuentra una diferencia significativa en la frecuencia de distribución de algunas de las especies de peces presentes en el río, además se observa un claro efecto barrera para la ictiofauna al eliminar la pista de trabajo.The Cigüela River and its tributary, Valdepineda (Cuenca, España) were affected by the crossing of a natural gas pipeline, in December 2001, by means of the conventional technique "open-cut water crossing" that consists of three different works: installation of the right-of-way, excavation and backfill of the pipeline trench, and restoration. In order to assess the impacts of these different activities on the aquatic environment, we are carrying out a study that is focused on the effects of suspended solids in the benthic and fish communities. Preliminary results of this study are presented on the excavation and backfill of the pipeline trench, that indicate that a very high value of suspended solids mobilisation is observed (up to 5000 mg/l), reaching the higher concentrations in the first 100 meters downstream of the crossing site. These suspended solids might be responsible for the significant increase in the sedimentation of the particles of sizes 50-250 μm and 250-500 μm in the 30 first meters downstream of the crossing site. On the other hand, we have not found differences in the values of the BMWP' index at the different sampling sites. Nevertheless, in the restoration phase , there is a significant difference in the distribution frequency of some fish species that appear in the river and also a clear barrier effect is observed for fishes when eliminating the right-of-way

    Characterization of size-sorted particulated matter collected on solid substrates by laser-ionization mass spectrometry and laser-induced breakdown spectrometry

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    Resumen de trabajos realizados mediante excitación láser de material particulado y su posterior análisis mediante espectroscopía óptica de emisión o ionización.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    When crystals become dust: Speleothem degradation processes in Praileaitz I Cave (Northern Spain)

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    Within the Praileaitz cave there are evident signs of deterioration of different types and generations, affecting both the host rock and the speleothems. The supports of many of the paintings, specifically the drapes, are in a clear state of deterioration due to disintegration of the texture of the speleothem, resulting from selective dissolution of the crystals and the creation of intercrystalline porosity. To analyse and study the different types of degradation and their causes, we gathered a total of 14 samples of speleothems and rock throughout the cave. The speleothems sampled are of different types and come from different growth phases. In order to monitor the parameters that may be causing the pathologies of degradation, a protocol was drawn up for measuring the environmental parameters and the condensation water and drip water in the cave. To analyse the water from the cave, samples were taken at four representative drip points in the cave and from condensation water.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Fire-related debris flows in the Iberian Range, Spain

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    38 páginas, 2 tablas, 11 figuras[EN] Debris flows occurred three weeks after a wildfire in August 1986 in the Najerilla River valley in the Iberian Range, northern Spain. The flows were triggered by a brief, intense rainstorm (approximately 25 mm h− 1 over 15 min) in a small area with steep slopes covered by a thick colluvium of quartzite clasts. This storm resulted in the development of several unconfined hillslope debris flows and the formation of an alluvial fan at the mouth of the Pítare stream, which partially blocked the Najerilla River. We analysed the conditions that led to the development of the debris flows, and estimated the rainfall threshold for the debris flows to occur as well as the total volume of mobilised sediment. Four factors contributed to the debris flows: (i) the occurrence of a rainstorm three weeks after a wildfire, which had removed the plant cover from the soil; (ii) the steep slopes in the area (> 30°), which were the most affected by debris flows; (iii) the presence of quartzite scarps on the hillslopes, which favoured the development of a ‘firehose effect’ involving channelised surface runoff; and (iv) the low plasticity index values of the fine material of the colluvium (indices of 7 to 8), which enabled rapid liquefaction. Estimates of rainfall intensity derived from the estimated peak flow in the Pítare stream suggests that around 80 mm of rainfall fell in approximately 15 min, although this is clearly an overestimated value given the high proportion of sediment load transported during the peak flow. Various equations estimated a rainfall-threshold of approximately 25 mm h− 1 considering a concentration time of 15 min. The total sediment transported by the debris flows was 10,500 m3 (15,750 Mg, 6800 Mg km− 2), and the Pítare stream alone transported a minimum of 4000 m3 (6000 Mg, 2500 Mg km− 2). These results suggest that the rainfall threshold for initiating debris flows decreases following a wildfire, such that an ordinary rainstorm is able to trigger a severe erosion and sediment transport event. Given the absence of fresh landslide scars on the hillslopes, the origin of the fire-related debris flows in the Najerilla River valley appears to have been directly linked to increased rates of overland flow having a greater effect than infiltration for triggering debris flows.Support for this research was provided by the projects PROBASE (CGL2006-11619/HID) and INDICA (CGL2011-27753-C02-01 and CGL2011-27753-C02-02), which was funded by the Spanish Ministry of Education and Science, and ACQWA (FP7-ENV-2007-1-212250), which was financed by the European Commission. Noemí Lana-Renault was the recipient of a research contract (Programme “Juan de la Cierva”, Human Resources Mobility, funded by the Spanish Ministry of Economy and Competitivity). The authors gratefully acknowledge Dr. Susan Canon, Dr. Francisco Gutiérrez-Santolalla and an anonymous reviewer for their comments and suggestions, which significantly helped to improve this paper.Peer reviewe

    Ensayos preliminares de germinación en Puya raimondii Harms (Bromeliaceae)

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    Puya raimondii Harms is an endemic especie of the highlands of Peru and Bolivia, whose population and area of distribution are being reduced. Aiming at contributing to the knowledge of the mechanisms of propagation of this species, a study of the effects of the illumination and stratification on the germination of the seed was carried out. The seed was collected in the rodal of Puya raimondii in Huashta Cruz (Pueblo Libre, Ancash) in December 1999 and were stored under laboratory conditions in Lima until the tests. The seeds were desinfected with sodium hipochloride 2,6% and for the germination test seeds were placed in petri dishes with distilled and sterilized water during 2000. The preliminary results show that the seed of Puya raimondii has a high percentage and velocity of germination when exposed to light. A similar effect was achieved by stratifying them for two months at 11 °C or by increasing time of storage to 8 months, but germination dropped upon applying both processes simultaneously. We hypothesize that the high seed moisture content and high temperature during storage and germination affect germination success negatively.Puya raimondii Harms es una especie endémica de la zona altoandina de Perú y Bolivia, cuyas poblaciones y área de distribución se están reduciendo. Con el objetivo de contribuir al conocimiento de los mecanismos de propagación de la especie se realizaron estudios del efecto de la iluminación y estratificación en la germinación de sus semillas. Éstas se colectaron en el rodal de P. raimondii de Huashta Cruz (Pueblo Libre, Áncash) en diciembre de 1999 y fueron almacenadas bajo condiciones de laboratorio en Lima, Perú, hasta el momento de los ensayos. Las semillas fueron desinfectadas con hipoclorito de sodio 2,6% y la germinación se realizó en placas petri con agua destilada estéril durante el año 2000. Los resultados preliminares muestran que las semillas de P. raimondii tienen altos valores de porcentaje e índice de velocidad de germinación al ser iluminadas. Efecto semejante tuvo estratificarlas por dos meses a 11 °C o incrementar el tiempo de almacenamiento hasta 8 meses pero resultó negativo aplicar los dos tratamientos a la vez. Se plantea que los altos contenidos de humedad de la semilla, temperatura de almacenamiento así como temperatura de germinación afectan negativamente los valores de germinación

    Coronavirus pandemic: an opportunity to study the anthropogenic impact on micro-climate conditions and CaCO3 crystal morphology in the Nerja Cave (SE Spain)

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    Following the declaration of the COVID-19 pandemic, the Spanish Government restricted non-essential movements of all citizens and closed all public spaces, such as the Nerja Cave, until May 31, 2020. This particular condition of the closure of the cave provided a unique opportunity to study the micro-climate conditions and carbonate precipitation in this tourist cave without the presence of visitors. Our results show the significant effect of visitors on the air isotopic signature of the cave and on the genesis of the extensive dissolution features affecting the carbonate crystals formed in the tourist sector of the cave, alerting us to the possible corrosion of the speleothems located there. The movement of visitors within the cave also favours the mobilisation of aerial fungi and bacterial spores and their subsequent sedimentation simultaneously with the abiotic precipitation of carbonates from the drip water. The traces of these biotic elements could be the origin of the micro-perforations previously described in the carbonate crystals formed in the tourist galleries of the cave, but they are subsequently enlarged due to abiotic dissolution of the carbonates through these weaker zones.It is financed by the Nerja Cave Foundation, co-ordinated by its Research Institute and authorized by the Consejería de Cultura (Junta de Andalucía). This study is also a contribution to the Research Groups RNM-308 and RNM-126 of the Junta de Andalucía and to the Projects PID2021-125619OB-C21, PID2021-125619OB-C22, TED2021-130549B-I00 funded by MCIN/AEI/10.13039/ 501100011033. Funding for open access charge: Universidad de Málaga / CBUA

    Effects of temperature and microbial disruption on juvenile kelp Ecklonia radiata and its associated bacterial community

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    Ocean warming can affect the development and physiological responses of kelps, and under future climate change scenarios, increasing seawater temperatures pose a major threat to these habitat-forming species. However, little is known about the effects of warming on epiphytic bacterial communities and how an altered microbiome may interact with temperature stress, affecting the condition and survival of kelp, particularly of the potentially more vulnerable early life stages. Here, we tested the effects of thermal stress on the growth and physiological responses of juvenile kelp Ecklonia radiata in which their epiphytic bacterial community was experimentally disrupted using antimicrobials, simulating dysbiosis. We hypothesized that, under thermal stress (23°C, simulating a extreme scenario of ocean warming in Tasmania), kelp with a disrupted bacterial community would be more strongly affected than kelp with an undisrupted microbiome or kelp under ambient temperature (14°C) but with a disrupted microbiota. Thermal stress reduced growth, increased tissue bleaching and negatively affected net photosynthesis of kelp. In addition, a substantial change in the epiphytic bacterial community structure was also found under thermal stress conditions, with an increase in the abundance of potentially pathogenic bacterial groups. However, microbial disruption did not act synergistically with thermal stress to affect kelp juveniles. These results suggest that effects of elevated temperature on juvenile kelps is not microbially-mediated and that juveniles may be less susceptible to disruptions of their microbiome

    Hydrogeological, hydrodynamic and anthropogenic factors affecting the spread of pharmaceuticals and pesticides in water resources of the Granada plain (Spain)

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    The anthropogenic organic contaminants contemplated in the environmental legislation, as well as those of emerging concern, threaten the quality of water resources to a degree that remains largely unknown. Contaminant exposure in the aquatic environment is a crucial element if a full understanding of the risk is pursued. There are still many uncertainties about the occurrence of organic pollutants and behavior in the hydro(geo)logical media in large scale areas. The case study of the unconfined aquifer of the Granada Plain (approximately 200 km2) is presented here. Two surface and groundwater monitoring campaigns were conducted (March 2017 and June 2018). In total, 41 out of 171 target organic pollutants were detected, at least once: 17 pharmaceuticals or drugs of abuse, 21 pesticides or their metabolites and three polyaromatic hydrocarbons. In addition, physico-chemical parameters were measured during the monitoring campaigns and hydrochemical parameters and stable isotopes (δ2H, δ18O, δ13C) were analyzed. Statistical tests confirmed the significance of seasonal changes for some of these parameters (e.g., EC, Cl-, F-, δ18O, δ13C), revealing the influence from snowmelt water input on streams and the intensification of irrigation. In March 2017, the group of pesticides (largely represented by triazines) predominated, whereas the frequency of detection of pharmaceuticals increased substantially in June 2018. Results suggest four main factors affecting the spatial and seasonal variation of organic pollutants in the aquifer: the anthropogenic factor determining the period of contaminant release throughout the year (pesticide application period and growth of tourism) along with irrigation practices that include reclaimed wastewater; unsaturated zone thickness; [...]This article is a contribution to the Research Groups RNM-308 and RNM 128 of the “Junta de Andalucía” and the project “Study, detection and behavior of emerging contaminants in anthropized watersheds in Andalusia-EMAN (P20_397)”. We are grateful to technical translation specialists GeoTranslations for proofreading the English version. We would also like to thank the Associate Editor, and the anonymous reviewers, who largely contributed to the improvement of the manuscript. Funding for open access charge: Universidad de Málaga / CBU

    Nanostructured Pt(NH3)4Cl2/SiO2 for nanomedicine: catalytic degradation of DNA in cancer cells

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    In vivo suppression of glioblastoma multiforme (GBM) in Wistar rats using silica-shelled biocatalytic Pt(NH3)4Cl2 nanoparticles is reported. These nanoparticles were synthesized by a sol-gel technique and characterized by SEM and HRTEM imaging. We confirmed morphological uniformity (30 nm) and surface acidity of the nanoparticles, respectively, by TEM imaging and FTIR spectral analysis. Interestingly, treatment of Wistar rats intraperitoneally inoculated with C6 cells using the biocatalysts resulted in considerable tumor shrinkage. Efficiency of the biocatalyst to shrink a tumor is superior to that by the commercial cytotoxic agent cisplatin. The tumor suppression property of Pt(NH3)4Cl2 nanoparticles is attributed to catalytic damage of DNA in C6 cells
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