Some Inverse Problems for the Burgers Equation and Related Systems

In this article we deal with one-dimensional inverse problems concerning the Burgers equation and some related nonlinear systems (involving heat effects and/or variable density). In these problems, the goal is to find the size of the spatial interval from some appropriate boundary observations of the solution. Depending on the properties of the initial and boundary data, we prove uniqueness and non-uniqueness results. In addition, we also solve some of these inverse problems numerically and compute approximations of the interval sizes

Preliminary study of the ostracods from the Lower Eocene Loza site (Álava, Basque-Cantabrian Basin)

In this paper the preliminary study of ostracods preserved in a distinct fossiliferous level within the poorly-known lower Eocene lacustrine-palustrine succession of Loza (Álava, Basque-Cantabrian Basin) is developed. The studied level is a 28cm thick marly interval including a thin whitish chalky level, interbedded between fine-grained limestones with variable proportions of gastropods and characean remains.With the aim of knowing the richnes of the ostracods and the prevailing palaeoenvironmental conditions during deposition of the lacustrine succession, two samples (L1 and L2), located within the marly interval respectively below and above the chalky level, have been studied. In L1 the most abundant genus is Limnocythere Brady, while in L2 the principal genera are Limnocythere and Cyclocypris Brady and Norman. According to the successive change in the ostracods, the fossiliferous level was deposited in a lacustrine environment,which was more saline and, probably, restricted over timeEn este trabajo se desarrolla un estudio preliminar de los ostrácodos preservados en un nivel fosilífero distintivo dentro de la pobremente conocida sucesión de origen palustre-lacustre del Eoceno inferior de Loza (Álava, Cuenca Vasco-Cantábrica). El nivel estudiado contiene un espesor de 28cm de margas incluyendo una fina banda calcítica blanca, intercalada entre calizas de grano fino con proporciones variables de gasterópodos y carofitas. Con el propósito de conocer la riqueza de ostrácodos y las condiciones paleoambientales predominantes durante el depósito de la sucesión lacustre, se han estudiado dos muestras (L1 y L2), situadas respectivamente por encima y por debajo de la banda blanca. En L1 el género más abundante es Limnocythere Brady, mientras que en L2 los géneros mayoritarios son Limnocythere y Cyclocypris Brady y Norman. De acuerdo a la variación de los ostrácodos identificados, el nivel fosilífero se depositó en un medio lacustre que fue más salino y, posiblemente, restringido con el tiemp

SAR Analysis of the ocean surface : aplication to the NW mediterranean marine pollution and dynamic features

The interaction between multiple scales in nature and mainly in turbulent flows produces fractals or multifractal structures. We use multi-fractal analysis to investigate the scales and influence of stratification in different types of surface eddies in the ocean, and specially, near the coastline. We will also show and discuss the structure and residence time in oil spills and slicks in the ocean surface. This method, of multifractal analysis on the intensity SAR signals, as an example will also be applied to experiments of unstable mixing fronts driven by Rayleigh-Taylor Instabilities. These hydrodynamic instabilities are a fundamental buoyancy or acceleration driven mixing process since they are the main causes of mixing and regulate for example the overturning process. A turbulent model is used in order to study the self-similar mixing process. The results are parameterized in terms of the Atwood number, which in terms of initial condition evaluation seems more convenient than using reduced gravity or buoyancy flux. The advance of the mixing front can be compared to several laboratory and field measurements, showing the effects of the initial perturbations and the two-dimensionality and boundary conditions of a model that combines 3 and 2 dimensional effects. The multi-fractal analysis reflects the flow conditions and allows us to understand further the mixing processes.Postprint (published version

Estudio numérico-experimental de la contaminación en aguas costeras

[ES] En este trabajo se presentan resultados numéricos y experimentales de la dispersión de contaminantes y trazadores en el litoral Mediterráneo. Se han utilizado dos modelos hidrodinámicos para simular la circulación horizontal producida por viento y oleaje en la plataforma y la zona de rompientes, respectivamente. Un modelo 3D de dispersión en "el campo cercano" suministra las condiciones iniciales al modelo 2D de dispersión local en el "campo lejano". Se presentan dos casos de estudio: la dispersión de trazadores en la zona de rompientes (Delta del Ebro) desde el punto de vista numérico y experimental; y la simulación de la dispersión de contaminantes urbanos -bacterias- provenientes del principal emisario submarino de Barcelona, mediante la aplicación de una secuencia de modelos numéricos. La comparación entre los experimentos y los resultados numéricos en la zona de rompientes es buena, mientras que las predicciones de contaminación en litoral cercano al emisario manifestaron la importancia de modelar con precisión los efectos de flotabilidad en el penacho o pluma. Además, se han simulado varias configuraciones de descarga, comprobándose que solo el nuevo emisario permite un grado de dilución acorde con la normativa vigente.El presente trabajo fue realizado como parte de los proyectos de investigación del LIM-UPC en Contaminación costera e Hidrodinámica de la Zona de Rompientes, financiados por el Direcc. Gral. de Medí Ambient de la Generalitat de Catalunya el primero, y conjuntamente por la Dirección Técnica Programa de Clima Marítimo (Ente Público Puertos del Estado -MOPTMA) y el Ministerio de E. y C. (DGICYT) el segundo. Los autores agradecen la colaboración de J.P. Sierra, J. Sospedra, J. Gomez y al personal involucrado en las mediciones de campo. También se agradece al Dr. G. Jirka sus comentarios sobre la dispersión en campo cercano y la disponibilidad del modelo CORMIX, y a EMSSA por la atención en suministrar datos de la planta y emisarios del Besos.Rodríguez, A.; Sánchez-Arcilla Conejo, A.; Bahía, E.; Redondo Apraiz, JM.; Collado, F. (1995). Estudio numérico-experimental de la contaminación en aguas costeras. Ingeniería del Agua. 2(2):53-62. https://doi.org/10.4995/ia.1995.2677SWORD536222Battjes, J. (1975). Modeling of turbulence in the surf zone, Proc. Sympo. on Modeling Techniques, ASCE, 1050-1061.Bravo, J. (1985). Analisis y Evaluación de la Calidad Microbiológica de las Aguas Costeras, Tesis Doctoral, Univ. Aut. de Barcelona, 257 pg.Carreras P. y Menendez A. (1990). Mathematical modelling of pollutant dispersion, Ecological modelling, Elsevier, 52, 29-40.Crickmore M.J. (1972). Tracer tests of eddy diffusion in field and model, Jour. Hyd. Div., ASCE, Vol. 98, no. HY10, 1737-1752.Deguchi I., Sawaragi T. y Ono M. (1992). Longshore current and lateral mixing in the surf zone. Proc. Int.Conf.Coast. Eng., ASCE, 2642-2654.Dean R. y Dalrymple, R. (1984). Water wave mechanics. Prentice-Hall, N. Jersey.Fredsoe J. (1984). The turbulent boundary layer in wave-current motion, Jour. Hyd. Eng., ASCE, Vol. 110, no. 8, 1103-1120.Harris T., Jordan J. McMurray W., Verwey C. y Anderson F. (1963). Mixing in the surf zone, Int.Jour. Air Wat. Poll., Vol. 7, 649-667.Holly F.M. y Usseglio-Polatera J.M. (1984). Dispersion Simulation in Two-Dimensional Tidal Flow, Jour. Hyd. Eng., ASCE, Vol. 110, no. 7(Julio), 905-926.Horikawa K., Lin M. y Sasaki T. (1978). Mixing of heated water discharged in the surf zone, Proc. Int.Conf.Coast.Eng., ASCE, 2563-2583.Jirka, G. (1991). CORMIX: Cornell Mixing Zone Expert System, I.C.E. Short Course on Hydraulics of Sea Outfalls, University of Honk Kong, Diciembre 1991.Mancini, J. (1978). Numerical estimates of coliform mortality rates under various conditions, Journal of water pollution control fed., Noviembre, 2477-2484.Mead C., y Cooper A. (1992). Three-dimensional numerical modelling of coastal hydrodynamics and pollutant dispersal, Proc. 2nd. Int. Conf. Hyd. and Env. Mod. of Coast., Est. and River Waters, Vol. 1, Ashgate Pub., 31-41.Mujeriego, R. (1989). Estudio del saneamiento de las zonas costeras de Cambrils y Vilaseca-Salou, Inf.Sec.Ing.Eng.Amb.}, DEHMA, ETSECCPB, UPC, Barcelona, Septiembre, 152 pg.Nadaoka K. y Hirose F. (1986). Modelling of diffusion coefficient in the surf zone based on physical process of wave breaking, Proc. 33rd Japan Conference Coastal Engineering, 26-30, (en japonés).Ozmidov, R. (1990). Diffusion of contaminants in the ocean, Oceanographie Sciences Library, Vol. 4, Kluwer Academic Publishers, Londres.Redondo J., Rodriguez A., Bahia E., Falqués A., Gracia V., Sánchez-Arcilla A. y Stive M.J.F. (1994). Image Analysis of Surf-Zone Hydrodynamics, Proc. Coastal Dynamics 94, ASCE, pp 350-365.Rodriguez A., Sánchez-Arcilla A., Collado F., Gracia V. y Coussirat M.G. (1994). Waves and currents at the Ebro Delta Surf Zone: measured and modelled Proc. Int.Conf.Coast.Eng., ASCE, (en prensa).Sánchez-Arcilla A.; Collado F., Lemos C. y Rivero F. (1990), Another quasi-3D model for surf-zone flows, ICCE, ASCE, pp 316-329.Sánchez-Arcilla A., Collado F., y Rodriguez A. (1992). Vertically varying velocity field in Q3D nearshore circulation, Proc. Int.Conf.Coast.Eng., ASCE, 2811-2838.Sierra J.P., Rodriguez A., Bahia E. y Sánchez-Arcilla A. (1994). Dispersió de contaminants en regions costaneres. Informe de recerca RR-LIM/ADC-94-1, Barcelona.Svendsen, I. (1987). Analysis of surf zone turbulence, Jour. Geophysical Research, 92 (C5), 5115-5124.Zeider R. (1976). Coastal Dispersion of Pollutants, Jour. Waterw. Harb. Coast. Eng., ASCE, Vol. 102, no. WW2 (May), 235-254

Evaluation of bioactive sphingolipids in 4-HPR-resistant leukemia cells

<p>Abstract</p> <p>Background</p> <p><it>N</it>-(4-hydroxyphenyl)retinamide (4-HPR, fenretinide) is a synthetic retinoid with potent pro-apoptotic activity against several types of cancer, but little is known regarding mechanisms leading to chemoresistance. Ceramide and, more recently, other sphingolipid species (e.g., dihydroceramide and dihydrosphingosine) have been implicated in 4-HPR-mediated tumor cell death. Because sphingolipid metabolism has been reported to be altered in drug-resistant tumor cells, we studied the implication of sphingolipids in acquired resistance to 4-HPR based on an acute lymphoblastic leukemia model.</p> <p>Methods</p> <p>CCRF-CEM cell lines resistant to 4-HPR were obtained by gradual selection. Endogenous sphingolipid profiles and in situ enzymatic activities were determined by LC/MS, and resistance to 4-HPR or to alternative treatments was measured using the XTT viability assay and annexin V-FITC/propidium iodide labeling.</p> <p>Results</p> <p>No major crossresistance was observed against other antitumoral compounds (i.e. paclitaxel, cisplatin, doxorubicin hydrochloride) or agents (i.e. ultra violet C, hydrogen peroxide) also described as sphingolipid modulators. CCRF-CEM cell lines resistant to 4-HPR exhibited a distinctive endogenous sphingolipid profile that correlated with inhibition of dihydroceramide desaturase. Cells maintained acquired resistance to 4-HPR after the removal of 4-HPR though the sphingolipid profile returned to control levels. On the other hand, combined treatment with sphingosine kinase inhibitors (unnatural (dihydro)sphingosines ((dh)Sph)) and glucosylceramide synthase inhibitor (PPMP) in the presence or absence of 4-HPR increased cellular (dh)Sph (but not ceramide) levels and were highly toxic for both parental and resistant cells.</p> <p>Conclusions</p> <p>In the leukemia model, acquired resistance to 4-HPR is selective and persists in the absence of sphingolipid profile alteration. Therapeutically, the data demonstrate that alternative sphingolipid-modulating antitumoral strategies are suitable for both 4-HPR-resistant and sensitive leukemia cells. Thus, whereas sphingolipids may not be critical for maintaining resistance to 4-HPR, manipulation of cytotoxic sphingolipids should be considered a viable approach for overcoming resistance.</p

Proteomics and the search for welfare and stress biomarkers in animal production in the one-health context

Stress and welfare are important factors in animal production in the context of growing production optimization and scrutiny by the general public. In a context in which animal and human health are intertwined aspects of the one-health concept it is of utmost importance to define the markers of stress and welfare. These are important tools for producers, retailers, regulatory agents and ultimately consumers to effectively monitor and assess the welfare state of production animals. Proteomics is the science that studies the proteins existing in a given tissue or fluid. In this review we address this topic by showing clear examples where proteomics has been used to study stress-induced changes at various levels. We adopt a multi-species (cattle, swine, small ruminants, poultry, fish and shellfish) approach under the effect of various stress inducers (handling, transport, management, nutritional, thermal and exposure to pollutants) clearly demonstrating how proteomics and systems biology are key elements to the study of stress and welfare in farm animals and powerful tools for animal welfare, health and productivity

Decline in age at menarche among Spanish women born from 1925 to 1962

<p>Abstract</p> <p>Background</p> <p>While the timing of reproductive events varies across populations, a downward trend in age at menarche has nevertheless been reported in most of the developed world over the past century. Given the impact of change in age at menarche on health conditions, this study sought to examine secular trends in age at menarche among women living in Navarre (Northern Spain) who participated in a population-based breast cancer screening programme.</p> <p>Methods</p> <p>The study was based on 110545 women born from 1925 to 1962. Trends were tested using a linear regression model, in which year of birth was entered continuously as the predictor and age at menarche (years) as the response variable, using size of town and region of birth as covariates.</p> <p>Results</p> <p>Among women born in Navarre between 1925 and 1962, age at menarche declined steadily from an average of 13.72 years in the 1925-1929 birth-cohorts to 12.83 years in the 1958-1962 birth-cohorts. Controlling for size of town or city of birth, age at menarche declined by an average of 0.132 years every 5 years over the period 1925-1962. This decline was greater in women born in rural versus urban settings. Trends were also different among regions of birth.</p> <p>Conclusion</p> <p>We report a population-based study showing a downward trend in age of onset of menarche among Spanish women born in the period 1925-1962, something that is more pronounced among women born in rural settings and varies geographically.</p

El Museo Naval de Donostia y la conservación del patrimonio flotante del ámbito pesquero. Marco conceptual-tipológico y embarcaciones recuperadas.

Barcos de pesca recuperados por el Museo Naval de San Sebastián: fundamentos, tipo de barcos, evolución...Untzi Museoa-Museo Naval de San Sebastian'ek berreskuratutako arraintza itsasontziak: oinarriak, ontzi motak, eboluzioa...Bateaux de pêche recuperés par l'Untzi Museoa-Museo Naval de San Sebastián: les types de bateaux, l'evolution des formes et des structures...Fishing boats recovered by the Untzi Museoa-Museo Naval de San Sebastián: basic concepts, boats types, evolution of desing..