Dynamics of the Pionium with the Density Matrix Formalism

The evolution of pionium, the $\pi^+ \pi^-$ hydrogen-like atom, while passing through matter is solved within the density matrix formalism in the first Born approximation. We compare the influence on the pionium break-up probability between the standard probabilistic calculations and the more precise picture of the density matrix formalism accounting for interference effects. We focus our general result in the particular conditions of the DIRAC experiment at CERN.Comment: 14 pages, 2 figures, submitted to J. Phys. B: At. Mol. Phy

Drought affects the performance of native oak seedlings more strongly than competition with invasive crested wattle seedlings

Two of the most important processes threatening vulnerable plant species are competitive displacement by invasive alien species and water stress due to global warming. Quercus lusitanica, an oak shrub species with remarkable conservation interest, could be threatened by the expansion of the invasive alien tree Paraserianthes lophantha. However, it is unclear how competition would interact with predicted reductions in water availability due to global climate change. We set up a full factorial experiment to examine the direct interspecific competition between P. lophantha and Q. lusitanica seedlings under control and water-limited conditions. • We measured seed biomass, germination, seedling emergence, leaf relative growth rate, biomass, root/shoot ratio, predawn shoot water potential and mortality to assess the individual and combined effects of water stress and interspecific competition on both species. • Our results indicate that, at seedling stage, both species experience competitive effects and responses. However, water stress exhibited a stronger overall effect than competition. Although both species responded strongly to water stress, the invasive P. lophantha exhibited significantly less drought stress than the native Q. lusitanica based on predawn shoot water potential measurements. • The findings of this study suggest that the competition with invasive P. lophantha in the short term must not be dismissed, but that the long-term conservation of the native shrub Q. lusitanica could be compromised by increased drought as a result of global change. Our work sheds light on the combined effects of biological invasions and climate change that can negatively affect vulnerable plant species

Carney triad. Report of one case

Indexación: Scopus.Carney described a disorder characterized by the presence of several uncommon tumors which were pulmonary chondromas, gastric sarcomas and extra-adrenal paragangliomas. We report a 14 year-old girl in whom multiple gastric tumors were discovered during a study of an iron deficiency anemia and was subjected to a partial gastrectomy. At 25 years of age, she developed several pulmonary chondromas and at 33 years, a mediastinal tumor with features of an extra-adrenal paraganglioma was found. At 35 years of age, a total gastrectomy was performed to remove a gastrointestinal stromal tumor with excision of peritoneal and lymph node metastasis. One year later, the patient died due to liver failure secondary to liver metastases.http://ref.scielo.org/4jhgg

El nuevo nuevo viejo oeste. Un paisaje sin lugar

El oeste es un mito tradicionalmente estadounidense que tiene entre sus rasgos distintivos la identificación con un determinado paisaje, elemento central en la definición de su significado. Sin embargo, el paisaje del oeste, como construcción cultural, se ha ido transformando a lo largo del siglo XX, asociándose a diferentes territorios, reales e imaginados. El artículo realiza un recorrido por algunas de sus principales reinterpretaciones, desde las primeras formalizaciones ofrecidas por la literatura y las artes de finales del siglo XIX hasta los actuales imaginarios reproducidos por el cine y la televisión. El oeste americano se muestra como un instrumento que sintetiza una determinada interpretación del territorio, la cultura y la sociedad norteamericana, configurando un modo particular de mirar y dotar de sentido a la realidad con la capacidad de adaptarse a diferentes contextos espaciales y temporales.If a modern myth is intimately connected with a territory, it is the American West. Transmitted by cinema, television, literature or advertising, the American West has transcended its status as a true American cultural reference, which was created at the same time as the historical reality on which it is based would disappear, to become a global topic that can not only be linked to a specific model of a society, but to a certain landscape as well. However, the western myth has not remained unchanged throughout the twentieth century, but it has been adapted to different historical contexts, which have allowed it revives at significant moments in American history not only as a mere fictional entertainment but also as a cultural reference that has been able to change the tangible (territorial) and intangible (social) reality. This paper aims to introduce and frame a widely known concept in the American context, the “New American West”, that raised from the revision of the original myth, focusing on its interpretation of territories and places. Starting from the shaping of the myth in the fictional westerns, the paper shows the original sources from which its landscape was defined and the characteristics that it represents. For this purpose, some significant stages in American Western history, coinciding with the times in which some huge alterations of the western territory were taken place, are analyzed, showing the new western-landscape representations and their narratives. This research seeks to establish an elemental basis from which the revival of the interest on the western myth and its landscape, both in USA and Europe, can be better understood, but it also reflects on landscape as a powerful tool to help us understand and change our environment

Stability assessment of a tailings storage facility using a non-local constitutive model accounting for anisotropic strain-softening

Recent failures of upstream-raised tailings storage facilities (TSF) raised con-cerns on the future use of these dams. While being cost-effective, they entail higher risks than conventional dams, as stability largely relies on the strength of tailings, which are loose and normally-consolidated materials that may exhibit strain-softening during un-drained loading. Current design practice involves limit equilibrium analyses adopting a fully-softened shear strength; while being conservative, this practice neglects the work input required to start the softening process that leads to progressive failure. This paper describes the calibration and application of the NGI-ADPSoft constitutive model to evaluate the potential of static liquefaction of an upstream-raised TSF and provides an indirect measure of resilience. The constitutive model incorporates undrained shear strength anisotropy and a mesh-independent anisotropic post-peak strain softening. The calibration is performed using laboratory testing, including anisotropically-consolidated triaxial compression tests and direct simple shear tests. The peak and residual undrained shear strengths are validated by statistical interpretation of the available CPTu data. It is shown that this numerical exercise is useful to verify the robustness of the TSF design.Comment: NGI-ADPSoft, Plaxis 2D, Strain-softening, Tailings, Static Liquefactio

Characterization and Engineering Properties of Dry and Ponded Class-F Fly Ash

Characterization studies conducted on Class-F fly-ash specimens gathered from different producers in the southeastern United States confirm general trends reported for fly ash worldwide. Additional tests and detailed analyses explain the spread in specific gravity (interparticle porosity cenospheres), highlight the tendency to segregation and layering, and show marked ferromagnetism. Furthermore, data show that early diagenetic cementation—within days after wetting—hinders densification and produces a fabric that is prone to collapse. New procedures are specifically developed to diagnose and characterize early diagenesis, including (1) pH measurements as an indicator of diagenetic potential, (2) test protocols to assess early diagenesis using oedometer tests and shear-wave velocity, and (3) procedures to determine realizable unit weights as reference values for the analyses of contractive or dilative tendencies and instability. In the absence of early diagenetic cementation, dilative fly-ash behavior is expected in the upper ≈20  m under monotonic shear loading. Flow instability may follow the failure of the containment structure if the ponded ash is saturated and has experienced hindered densification

Direct calculation of the probability of pionium ionization in the target

We performed the first direct calculation of the probability of pionium (pi+pi- atom) ionization in the target. The dependence of the probability of pionium ionization in the target as a function of the pionium lifetime is established. These calculations are of interest of the DIRAC experiment at CERN, which aims to measure the pionium lifetime with high precision.Comment: 11 pages, 4 figures; submitted to "Physics of Atomic Nuclei" ("Yadernaya Fizika"

Estimation of the hydraulic parameters of unsaturated samples by electrical resistivity tomography

In situ and laboratory experiments have shown that electrical resistivity tomography (ERT) is an effective tool to image transient phenomena in soils. However, its application in quantifying soil hydraulic parameters has been limited. In this study, experiments of water inflow in unsaturated soil samples were conducted in an oedometer equipped to perform three-dimensional electrical measurements. Reconstructions of the electrical conductivity at different times confirmed the usefulness of ERT for monitoring the evolution of water content. The tomographic reconstructions were subsequently used in conjunction with a finite-element simulation to infer the water retention curve and the unsaturated hydraulic conductivity. The parameters estimated with ERT agree satisfactorily with those determined using established techniques, hence the proposed approach shows good potential for relatively fast characterisations. Similar experiments could be carried out on site to study the hydraulic behaviour of the entire soil deposi

ALERT Doctoral School 2012: advanced experimental techniques in geomechanics

The twenty-second session of the European Graduate School 2012 (called usually ALERT Doctoral School) entitled Advanced experimental techniques in geomechanics is organized by Cino Viggiani, Steve Hall and Enrique Romero.Postprint (published version