On the new translational shape invariant potentials

Recently, several authors have found new translational shape invariant potentials not present in classic classifications like that of Infeld and Hull. For example, Quesne on the one hand and Bougie, Gangopadhyaya and Mallow on the other have provided examples of them, consisting on deformations of the classical ones. We analyze the basic properties of the new examples and observe a compatibility equation which has to be satisfied by them. We study particular cases of such equation and give more examples of new translational shape invariant potentials.Comment: 9 pages, uses iopart10.clo, version

Shear-melting of a hexagonal columnar crystal by proliferation of dislocations

A hexagonal columnar crystal undergoes a shear-melting transition above a critical shear rate or stress. We combine the analysis of the shear-thinning regime below the melting with that of synchrotron X-ray scattering data under shear and propose the melting to be due to a proliferation of dislocations, whose density is determined by both techniques to vary as a power law of the shear rate with a 2/3 exponent, as expected for a creep model of crystalline solids. Moreover, our data suggest the existence under shear of a line hexatic phase, between the columnar crystal and the liquid phase

Charmed hadrons in nuclear medium

We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances.Comment: 4 pages, 5 figures, invited parallel talk in the 5th International Conference on Quarks and Nuclear Physics (QNP09), Beijing, September 21-26, 200

Synthesis, structure and physical properties of a low dimensional compound

The crystal structure of (µ3-oxo)hexakis(cyanoacetato-¿O, O')(cyanoacetato-¿O)diaquatriiron(III) cyanoacetic acid shows the formation of trinuclear complexes in a hydrogen-bond network that bonds all the molecules in a 3D arrangement. For this complex, within whose clusters the whole magnetic interaction takes place, 57Fe Mössbauer spectroscopy shows that the Fe cations are in the S = 5/2 state in the temperature range 2–295 K. The asymmetric broadening of the absorption peaks below 80 K is consistent with strong antiferromagnetic interactions between the metal spins. The magnetization measurements also show the antiferromagnetic character of the spin ensemble and an ST = 1/2 magnetic ground state typical of triangular systems with similar J between Fe-Fe pairs

La reforma agraria agroecológica como camino hacia la sostenibilidad: un estudio de caso en Brasil.

Resumen: El modelo agroexportador actualmente en marcha en Brasil, basado en el agronegocio y los grandes monocultivos para la producción de commodities, tiene intrínsecas limitaciones en alcanzar de manera satisfactoria las múltiples dimensiones de la sostenibilidad planteadas por la agroecología y la soberanía alimentaria. En base a un estudio de caso (un asentamiento campesino agroecológico en la región cañera de Ribeirão Preto, estado de São Paulo), argumentamos que los procesos de transición hacia la sostenibilidad en zonas dominadas por estos grandes monocultivos agroindustriales pueden ser viables a partir de un nuevo modelo de reforma agraria de base agroecológica, que impulse procesos sociales de construcción de alternativas más sostenibles en el campo. Las evidencias obtenidas en la investigación nos permiten plantear que la reforma agraria, y las políticas agroecológicas asociadas, tienen un importante papel de recuperar la agrobiodiversidad y hacer emerger ?memorias campesinas? que de otra forma estarían condenadas al olvido, abriendo las posibilidades para un proceso de recampesinización en contraposición al modelo de desarrollo hegemónico en la región. Concluimos que la perspectiva agroecológica permite una resignificación de la reforma agraria, en la medida que no la restringe a una dimensión solamente económico-productivista, rescatando su naturaleza multidimensionaly rompiendo el histórico divorcio entre la ?cuestión agraria?y la ?cuestión ambiental? en Brasil

Open charm meson in nuclear matter at finite temperature beyond the zero range approximation

The properties of open charm mesons, $D$, $\bar D$, $D_s$ and $\bar D_s$ in nuclear matter at finite temperature are studied within a self-consistent coupled-channel approach. The interaction of the low lying pseudoscalar mesons with the ground state baryons in the charm sector is derived from a $t$-channel vector-exchange model. The in-medium scattering amplitudes are obtained by solving the Lippmann-Schwinger equation at finite temperature including Pauli blocking effects, as well as $D$, $\bar D$, $D_s$ and $\bar D_s$ self-energies taking their mutual influence into account. We find that the in-medium properties of the $D$ meson are affected by the $D_s$-meson self-energy through the intermediate $D_s Y$ loops coupled to $DN$ states. Similarly, dressing the $\bar{D}$ meson in the $\bar{D}Y$ loops has an influence over the properties of the $\bar{D}_s$ meson.Comment: 23 pages, 9 figures, 2 table

Strange and charm mesons at FAIR

We study the properties of strange and charm mesons in hot and dense matter within a self-consistent coupled-channel approach for the experimental conditions of density and temperature expected for the CBM experiment at FAIR/GSI. The in-medium solution at finite temperature accounts for Pauli blocking effects, mean-field binding of all the baryons involved, and meson self-energies. We analyze the behaviour in this hot and dense environment of dynamically-generated baryonic resonances together with the evolution with density and temperature of the strange and open-charm meson spectral functions. We test the spectral functions for strange mesons using energy-weighted sum rules and finally discuss the implications of the properties of charm mesons on the D_{s0}(2317) and the predicted X(3700) scalar resonances.Comment: 12 pages, 9 figures, invited talk at XXXI Mazurian Lakes Conference on Physics: Nuclear Physics and the Road to FAIR, August 30-September 6, 2009, Piaski, Polan

First report of a Late Jurassic lizard-like footprint (Asturias, Spain)

This report describes an isolated footprint preserved as a natural cast (convex hyporelief) from the Lastres Fm. (Late Jurassic) of northern Spain. The track consists of a small isolated pentadactyl ectaxonic right manus footprint. It is very asymmetric, plantigrade, with digits and palm deeply marked on the substrate. Digit IV is the longest, digits II and I are nearly equal in length and only a little shorter than III and IV. The footprint morphology is typical of a lizard – like or “lacertoid” track .The general outline of the footprint, the width to length ratio approximately equal to 1, the marked plantigrady and the substantial similarity in length of digits IV-I are coherent with a Rhynchosauroidea manual print. The global record of Rhynchosauroides ichnogenus shows that this specimen represents the latest occurrence of the ichnogenus. The most probable trackmaker was possibly a rhyncocephalian reptile.Se describe una huella de mano aislada, preservada como contramolde natural (hiporrelieve convexo) de la Formacion Lastres (Jurasico Superior) del N de Espana. La icnita, aislada, pentadactila, ectaxonica y de pequeno tamano, es atribuida a una mano derecha. Es muy asimetrica y plantigrada, con los dedos y la palma profundamente impresos en el sustrato. El dedo IV es el mas largo, mientras que el II y el I son casi iguales en longitud y solamente un poco mas cortos que el III y el IV. La morfologia de la huella es tipica de un lagarto o “lacertoide”. El contorno de la huella, la relacion longitud/anchura en torno a 1, la longitud similar de los dedos I-IV y el hecho de que sea claramente plantigrada son rasgos coherentes con una huella de mano de un Rhynchosauroidea. El registro global de Rhynchosauroides indica que el ejemplar asturiano representa la evidencia mas reciente de este icnogenero. El autor de la huella fue probablemente un reptil rincocefalo