Boundary controllability for a 1D degenerate parabolic equation with a Robin boundary condition

In this paper we prove the null controllability of a one-dimensional degenerate parabolic equation with a weighted Robin boundary condition at the left endpoint, where the potential has a singularity. We use some results from the singular Sturm-Liouville theory to show the well-posedness of our system. We obtain a spectral decomposition of a degenerate parabolic operator with Robin conditions at the endpoints, we use Fourier-Dini expansions and the moment method introduced by Fattorini and Russell to prove the null controllability and to obtain an upper estimate of the cost of controllability. We also get a lower estimate of the cost of controllability by using a representation theorem for analytic functions of exponential type.Comment: arXiv admin note: substantial text overlap with arXiv:2304.00178, arXiv:2302.0119

Design and validation of the soccer tactical knowledge test (STKT)

El propósito de este estudio fue determinar la validez de un test de evaluación del conocimiento táctico en fútbol. Siete expertos revisaron el instrumento y 465 niños/as de entre 8-14 años fueron encuestados. El 100% de acuerdo entre los expertos, la consistencia interna (α=.87), la correlación Testretest (r=.75) y la correlación entre el conocimiento táctico y el criterio externo de entrenadores de fútbol (p<.01), sugirieron que el instrumento era fiable. El contexto deportivo se mostró determinante sobre el nivel de conocimiento táctico (p<.01) apoyando la validez de constructo y concurrente. Estos resultados confirmaron la validez del instrumento para evaluar el conocimiento táctico en fútbol de jóvenes que se inician a los deportes de equipoThe purpose of the present study was to determine the validity of a tactical knowledge assessment test in soccer. Seven experts reviewed the instrument and 465 children aged 8 to 14 years completed the test. The experts’ opinion (100% agreement), internal consistency (α=.87), Test-retest correlation (r=.75), and the correlations between the soccer tactical knowledge and the external criterion of soccer coaches (r=.46, p<.01), showed reasonable evidence for assessing the test reliability. The sport context was determinant on the tactical knowledge (p<.01), supporting construct and concurrent validity. These results verify the validity of this instrument for assessing soccer tactical knowledge in young beginners who are starting to practice team sport

Nota sobre la taxonomía de Microtus (Iberomys) (Arvicolinae, Rodentia) del Pleistoceno superior de la Gruta do Caldeirão (Tomar, Portugal) e interpretación paleoclimática de la asociación de roedores

Gruta do Caldeirão is an archaeological cave site located in Tomar (Portugal, western Iberian Peninsula), which contains an important Late Pleistocene sequence from Middle Paleolithic (Mousterian) to Upper Paleolithic (Solutrean-Magdalenian), including lithic tools, human remains, and other large- and small-vertebrate remains. Our revision and interpretation of the rodent assemblage previously published in the 1990s leads to three important conclusions: 1) the only species of the subgenus Iberomys present in the sequence is the current endemic Iberian vole species Microtus (Iberomys) cabrerae (Cabrera’s vole); 2) the rodent assemblage is dominated through­out by open-forest species, such as the long-tailed field mouse (Apodemus sylvaticus), and species associated with open-humid areas such as the Mediterranean and Lusitanian pine voles (Microtus (Terricola) spp.), with the notable presence of an extinct hamster (Allocricetus bursae) in layer K, and three vole species not currently found in the vicinity of the cave (Microtus arvalis [the common vole], M. Agrestis [the field vole], and Chionomys nivalis [the European snow vole]) also in the assemblage; 3) the bioclimatic model, which is used to reconstruct climatic parameters on the basis of the rodent association, corroborates the proposal that the Solutrean occupation from layers H to Fa took place during a cold period equated to the Last Glacial Maximum (LGM), as indicated by the available radiocarbon dates and supported by the magnetic susceptibility data.Gruta do Caldeirão es un yacimiento arqueológico en cueva situado en Tomar (Portugal, oeste de la península Ibérica), que contiene una importante secuencia perteneciente al Pleistoceno superior, adscrita culturalmente al Paleolítico medio (Musteriense) y Paleolítico superior (Solutrense-Magdaleniense), que incluye industria lítica, restos humanos y restos de grandes y pequeños vertebrados. La revisión e interpretación de la asociación de roedores de la secuencia, previamente publicada en los años 90 del siglo pasado, nos ha permitido remarcar tres importantes conclusiones: 1) la única especie del subgénero Iberomys presente en la secuencia es la espe­cie endémica actual de topillo Microtus (Iberomys) cabrerae (topillo de Cabrera); 2) la asociación de roedores está dominada en toda la secuencia por especies relacionadas con bosques abiertos, como el ratón de campo (Apodemus sylvaticus) y especies relacionadas con espacios abiertos-húmedos como los topillos mediterráneo y lusitánico (Microtus (Terricola) spp.), remarcando la presencia de un hámster extinto (Allocricetus bursae) en el nivel K y tres especies de topillos que no tienen representación actual en la zona circundante a la cavidad (Microtus arvalis - topillo campesino, Microtus agrestis – topillo agreste y Chionomys nivalis - topillo nival); 3) Finalmente, el método del Modelo Bioclimático, aplicado a la asociación de roedores, otorga resultados acordes con que la ocupaciones solutrenses situadas entre los niveles H y Fa están relacionadas con un periodo frío equi­parado con el Último Máximo Glacial (LGM), indicado por las dataciones de radiocarbono y anteriores estudios de susceptibilidad magnética de la secuencia

Synoptic patterns associated with wildfires caused by lightning in Castile and Leon, Spain

The Iberian Peninsula presents the highest number of wildfires in Europe. In the NW of Spain in particular, wildfires are the natural risk with the greatest economic impact in this region. Wildfires caused by lightning are closely related to the triggering of convective phenomena. The prediction of thunderstorms is a very complex task because these weather events have a local character and are highly dependent on mesoscale atmospheric conditions. The development of convective storms is directly linked to the existence of a synoptic environment favoring convection. The aim of this study is to classify the atmospheric patterns that provide favorable environments for the occurrence of wildfires caused by lightning in the region of Castile and Leon, Spain. The database used for the study contains 376 wildfire days from the period 1987–2006. NCEP data reanalysis has been used. The atmospheric fields used to characterise each day were: geopotential heights and temperatures at 500 hPa and 850 hPa, relative humidity and the horizontal wind at 850 hPa. A Principal Component Analysis in T-mode followed by a Cluster Analysis resulted in a classification of wildfire days into five clusters. The characteristics of these clusters were analysed and described, focusing particularly on the study of those wildfire days in which more than one wildfire was detected. In these cases the main feature observed was the intensification of the disturbance typical of the cluster to which the wildfire belongs

Study of 11 September 2004 hailstorm event using radar identification of 2-D systems and 3-D cells

The most important hail event recorded in the region of the Ebro Valley (NE Spain) in 2004 was the 11 September episode. Large hailstones (some of them with a diameter of over 30 mm) caused important damages in agriculture and properties. The hail event affected an area of 3848 ha and was caused by several multicellular systems. The aim of this paper is the analysis of the associated convective structures using the meteorological radar as well as the MM5 mesoscale model, thermodynamic data and a hailpad network. To achieve this end, the new hailstorm analysis tool RHAP (Rainfall events and Hailstorms Analysis Program) has been applied. It identifies tracks and characterises precipitation systems and convective cells, taking into account 2-D and 3-D structures. The event has also been studied with the TITAN software (Thunderstorm Identification, Tracking, Analysis and Nowcasting) in an attempt to compare both methods. Results show that the episode had a strong convective activity with CAPE values over 4000 J/kg and with hail-forming cells characterised by VIL (Vertical Integrated Liguid) exceeding 40 kg/m², VILD (VIL density) over 4 g/m³, HP (Hail Probability) of 100% and SHP (Severe Hail Probability) of over 75%. The hail cells evolved into multicellular systems that lasted between 70 and 90 min. Finally, the comparison of RHAP and TITAN has shown significant correlations between methods

Carbon and oxygen abundances from recombination lines in low-metallicity star-forming galaxies. Implications for chemical evolution

We present deep echelle spectrophotometry of the brightest emission-line knots of the star-forming galaxies He 2-10, Mkn 1271, NGC 3125, NGC 5408, POX 4, SDSS J1253-0312, Tol 1457-262, Tol 1924-416 and the HII region Hubble V in the Local Group dwarf irregular galaxy NGC 6822. The data have been taken with the Very Large Telescope Ultraviolet-Visual Echelle Spectrograph in the 3100-10420 {\AA} range. We determine electron densities and temperatures of the ionized gas from several emission-line intensity ratios for all the objects. We derive the ionic abundances of C$^{2+}$ and/or O$^{2+}$ from faint pure recombination lines (RLs) in several of the objects, permitting to derive their C/H and C/O ratios. We have explored the chemical evolution at low metallicities analysing the C/O vs. O/H, C/O vs. N/O and C/N vs. O/H relations for Galactic and extragalactic HII regions and comparing with results for halo stars and DLAs. We find that HII regions in star-forming dwarf galaxies occupy a different locus in the C/O vs. O/H diagram than those belonging to the inner discs of spiral galaxies, indicating their different chemical evolution histories, and that the bulk of C in the most metal-poor extragalactic HII regions should have the same origin than in halo stars. The comparison between the C/O ratios in HII regions and in stars of the Galactic thick and thin discs seems to give arguments to support the merging scenario for the origin of the Galactic thick disc. Finally, we find an apparent coupling between C and N enrichment at the usual metallicities determined for HII regions and that this coupling breaks in very low-metallicity objects.Comment: 27 pages, 12 figures, Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Genomic Evolution of Two Acinetobacter baumannii Clinical Strains from ST-2 Clones Isolated in 2000 and 2010 (ST-2_clon_2000 and ST-2_clon_2010)

Acinetobacter baumannii is a successful nosocomial pathogen due to its ability to persist in hospital environments by acquiring mobile elements such as transposons, plasmids, and phages. In this study, we compared two genomes of A. baumannii clinical strains isolated in 2000 (ST-2_clon_2000) and 2010 (ST-2_clon_2010) from GenBank project PRJNA308422

Studies of mass transfer coefficients in denitrifying biofilms

Mass transfer coefficients within denitrifying biofilms were determined with an inert compound (LiCl) using two different flow conditions in a membrane flow cell and feeding an easily degradable substrate. The experiments were made until the biofilm reached steady state. The results obtained from the biofilm mass transfer experiments show that the biofilms grown under these two different conditions reach similar values in the steady state. However, the mass transport was higher during biofilm formation, for the biofilm developed under higher upflow velocity.Comissão Europeia, TMR program (project BioToBio); Spanish CICYT (project AMB 98-0288)

Use of a membrane flow cell to measure average mass transfer coefficients in denitrifying biofilms

Average mass transfer coefficients within denitrifying biofilms were determined during biofilm growth with an inert compound (LiCl) in a membrane flow cell at different flow conditions, until the biofilm reached (pseudo-) steady state. Similar values were obtained for the steady-state mass transfer coefficients of LiCl within the different biofilms. However, those coefficients were higher during the transient period of biofilm growth for the biofilm developed under the highest upflow velocity.Xunta de Galicia, project BioToBi