Phase transition in a super superspin glass

We here confirm the occurrence of spin glass phase transition and extract estimates of associated critical exponents of a highly monodisperse and densely compacted system of bare maghemite nanoparticles. This system has earlier been found to behave like an archetypal spin glass, with e.g. a sharp transition from paramagnetic to non-equilibrium behavior, suggesting that this system undergoes a spin-glass phase transition at a relatively high temperature, $T_g$ $\sim$ 140 K.Comment: 4 pages, 3 figure

Lifestyle Influence on the Content of Copper, Zinc and Rubidium in Wild Mushrooms

The concentration of 18 trace elements in several species of fungi (arranged in three groups: ectomycorrhizae, saprobes, and epiphytes) has been determined. The measurements were made using the methodology of X-ray fluorescence. Higher contents of Cu and Rb (with statistical support) have been found in the ectomycorrhizal species. The Zn content reached higher concentrations in the saprophytic species. According to the normality test and the search for outliers, the species Clitocybe maxima and Suillus bellini accumulate large amounts of Cu and Rb, respectively, so that both can be named as “outliers.” The leftwards displacement of the density curves and their nonnormality are attributed to the presence of these two species, which exhibit hyperaccumulation skills for Cu and Rb, respectively. Regarding Zn absorption, no particular species were classified as outlier; therefore it can be assumed that the observed differences between the different groups of fungi are due to differences in their nutritional physiology

EVIDENCES OF THE EARLY CRETACEOUS VOLCANISM IN THE YAVI FORMATION NEAR THE ATACO (TOLIMA) COLOMBIA AND ITS GEODYNAMICS IMPLICATIONS

  Proximal volcanism deposits are reported by the first time inter-bedded in Early Cretaceous age sedimentites at the Upper Magdalena Valley. Lapilli tuff, ignimbrites and coarse ash tuff were found outcropping along the road Ataco-Coyaima (Tolima Department) at the upper part of the Yaví Formation. The volcanic rocks fall in the subalcaline and toleitic fields. It is speculate if that volcanism could have connection with contemporary magmatic activity at the Quebradagrande Complex, Oriente basin in Ecuador and Cundinamarca sub-basin in Colombia.   Key words: Volcanism, Yaví Formation, Early Cretaceous, Geodinamic  Por primera vez se reportan productos de volcanismo proximal en depósitos de edad Cretácica Temprana del Valle Superior del Magdalena. Tobas riodacíticas, ignimbritas y tobas de lapilli fueron identificadas en la parte superior de la Formación Yaví entre Ataco y Coyaima (Departamento del Tolima). Las rocas volcánicas se ubican en los campos subalcalino y toleítico. Se especula sobre las relaciones que este volcanismo podría tener con fenómenos magmáticos contemporáneos en el Complejo Quebradagrande, cuenca de Oriente en Ecuador y subcuenca de Cundinamarca en Colombia.   Palabras clave: Volcanismo, Formación Yaví, Cretácico Temprano, Geodinámico   &nbsp

Geoquímica de las rocas del stock Chinchiná - Santa Rosa

 In this study, appears the first analytical results of major elements, trace and rare earth of the protomilonitas of the Stock Chinchiná-Santa Rosa, it is in the Western flank of the Central belt, between the faults Silvia-Pijao, eastwards and Cauca-Almaguer, on the west. The geochemistry characterization in the rocks that they formed in the Stock indicates that this one belongs to the subalkaline series with character toleítico and they are clasified like gabbros and madaly as metagabbro that change according to the grade of deformation between the cataclasites and the milonites. Tectonic discrimination diagrams, allowed to establish that the generation of intrusive body in an dominion distensive of dorsal oceanic type N-MORB; the identification of this environment will allow to set this body in a geotectonic position, forming a part of a complex ophiolitic.En este estudio, se presentan los primeros resultados analíticos de elementos mayores, traza y tierras raras de las rocas que conforman el Stock Chinchiná-Santa Rosa, localizado en el flanco Occidental de la Cordillera Central, entre las fallas Silvia-Pijao, al este y Cauca-Almaguer, al oeste. Los datos geoquímicos de este cuerpo indican que pertenece a la serie subalcalina con carácter toleítico, geoquímicamente se clasifican como gabros y modalmente como metagabros con un grado de deformación que varía de cataclasita a milonita. Los diagramas de discriminación tectónica, permiten establecer que la generación del cuerpo intrusivo ocurrió en un dominio distensivo de dorsal oceánica tipo N-MORB; la identificación de este ambiente permite posicionar geotectónicamente a este cuerpo, como parte de un complejo ofiolítico.   &nbsp

A model of Mira's cometary head/tail entering the Local Bubble

We model the cometary structure around Mira as the interaction of an AGB wind from Mira A, and a streaming environment. Our simulations introduce the following new element: we assume that after 200 kyr of evolution in a dense environment Mira entered the Local Bubble (low density coronal gas). As Mira enters the bubble, the head of the comet expands quite rapidly, while the tail remains well collimated for a 100 kyr timescale. The result is a broad-head/narrow-tail structure that resembles the observed morphology of Mira's comet. The simulations were carried out with our new adaptive grid code WALICXE, which is described in detail.Comment: 12 pages, 8 figures (4 in color). Accepted for publication in The Astrophysical Journa

Proteome analysis during a new chondrogenesis model from mesenchymal stem cells of human umbilical cord stroma

Comunicaciones a congreso

Radiation-damage produced in BaHfO₃ irradiated with thermal and fast-neutrons

Samples of BaHfO₃ were irradiated with fast and thermal neutrons to produce ^181Hf. Attenuations of the gamma-gamma perturbed angular correlations in ^181Ta were observed, and they may have been caused by the interaction between defects (produced during or after neutron irradiation) and oxygen vacancies. Several defect structures were detected. For one of the structures, an excitation energy of 12 meV was measured, which was attributed to an electron state below the conduction band. The values of the dielectric constant and of the effective electron mass were also deduced

Phase transitions of hadronic to quark matter at finite T and \mu_B

The phase transition of hadronic to quark matter and the boundaries of the mixed hadron-quark coexistence phase are studied within the two Equation of State (EoS) model. The relativistic effective mean field approach with constant and density dependent meson-nucleon couplings is used to describe hadronic matter, and the MIT Bag model is adopted to describe quark matter. The boundaries of the mixed phase for different Bag constants are obtained solving the Gibbs equations. We notice that the dependence on the Bag parameter of the critical temperatures (at zero chemical potential) can be well reproduced by a fermion ultrarelativistic quark gas model, without contribution from the hadron part. At variance the critical chemical potentials (at zero temperature) are very sensitive to the EoS of the hadron sector. Hence the study of the hadronic EoS is much more relevant for the determination of the transition to the quark-gluon-plasma at finite baryon density and low-T. Moreover in the low temperature and finite chemical potential region no solutions of the Gibbs conditions are existing for small Bag constant values, B < (135 MeV)^4. Isospin effects in asymmetric matter appear relevant in the high chemical potential regions at lower temperatures, of interest for the inner core properties of neutron stars and for heavy ion collisions at intermediate energies.Comment: 24 pages and 16 figures (revtex4

P-T OF THE ACTINOLITIC SCHIST OF THE CAJAMARCA COMPLEX TO THE SOUTHEAST THE MONTEBELLO, ANTIOQUIA

&nbsp; La historia de evolución presión y temperatura (P-T) para los esquistos actinolíticos en el sector suroccidental del municipio de Montebello, departamento de Antioquia, revelan un peak de temperaturas entre 320 a 475 ºC y presiones de 2 a 6 kilobares, con base en las relaciones texturales y termobarométricas de los minerales metamórficos. Los datos de (P-T-t) definen una posible trayectoria antihoraria y en el campo de las facies de los esquistos verdes. El protolito de estas rocas corresponde a basaltos generados en zonas de dorsal oceánica confirmado, además, por la fase mineral ígnea. &nbsp; Palabras claves: Termobarometría, esquistos actinolíticos, Complejo Cajamarca &nbsp;&nbsp; &nbsp;&nbsp; The P-T conditions were determinated in actinolitics schist of the basament of the Colombian Central Cordillera, in the southeast sector of Montebello, (Antioquia), the estimation of the pressure and temperature conditions was from 320 to 475 °C and 2 to 6 kbar; according to the textural and thermobarometric relations of the metamorphic minerals. A reconstruction in space and time of these P-T-t paths allows an estimate counterclockwise evolution in the greenschist facies field. The protolith of these rocks indicates them to be derived from oceanic floor basalts, in adition, for the igneous mineral phase. &nbsp; Key words : Thermobarometry, actinolitic schist, Cajamarca Complex &nbsp

Estudio de los efectos de algunos psicotropos en el test "Open Field"

Por medio del test "opcn-field" se ha analizado el comportamiento de ratas tratadas con diversos psicotropos ncurolépt icos. antidcpresivos, tranquilizntes, barbitú ricos, psicoana l~pt icos) y asociaciones, entre las que figura la de un IMAO (nialamida) y 5-hidroxitriptofano, precusor de la serotonina cerebral. De los resultados obtenidos se deduce que los neurolépticos dieron lugar a una marcada reducción de la motilidad, en tanto que el clordiacepóxido y el fenobarbilal produjeron el efecto con· trario, probablemente como expresión de un efecto ansiolítico notable. La asociación de nialamida y 5-hidroxitriptofano dió lugar a una reducción muy significativa de la deambulación de las ratas tratadas, sugiriéndose una participación de la serotonina en los circuitos moduladores de la actividad de las ratas. Este descenso de movilidad fue hallado, asimtsmo, con la imipramina, r~lacio nándose también, este fenómeno, con una posible intensificación de sistemas serotoninérgicos. En cuanto a la intervención de los psicotropos sobre las estereotipias y las emisiones de bolos fecales, no se han encontrado resultados capaces de informar con eficacia, sobre la utilidad de estos dos parámetros como medida para la "emotividad"