H2 distribution during 2-phase Molecular Cloud Formation

We performed high-resolution, 3D MHD simulations and we compared to observations of translucent molecular clouds. We show that the observed populations of rotational levels of H2 can arise as a consequence of the multi-phase structure of the ISM.Comment: 2 pages, 1 figure. Due to appear in the proceedings of the 6th Zermatt ISM Symposium: "Conditions and Impact of Star Formation: From Lab to Space

Minimal AdS-Lorentz supergravity in three-dimensions

The $\mathcal{N}=1$ AdS-Lorentz superalgebra is studied and its relationship to semigroup expansion developed. Using this mathematical tool, the invariant tensors and Casimir operators are found. In terms of these invariants, a three-dimensionnal Chern--Simons supergravity action with AdS-Lorentz symmetry is constructed. The Killing spinors for a BTZ black-hole like solution of the theory are discussed.Comment: 18 pages, matches published versio

Factores Psicológicos Asociados a la Maternidad Adolescente en Menores de 15 años.

The present research analyzes psychological variables associated with Adolescentmotherhood; comparing young mothers under 15 years old, with mothers between 20 and 34 years old, and adolescents non mothers neither pregnant in a comparative descriptive transversal study. The adult mothers didn’t show significant higher levels of perceived social support than adolescent mothers under 15 years old (p=0.46), neither a significant higher intelectual level than adolescent mothers under 15 years old (p=0.23). Besides, it didn’t show a higher total self-steem level than adolescent mothers under 15 years old (p=0.5). Nevertheless, the adolescent mothers had a significant higher level of social self-steem than the adult mothers (p=0.036). The adolescents nonmothers, didn’t show a higher level of perceived social support, than the adolescents mothers (p=0.45) and in the sub-scale, perceived social support from others; the adolescent mothers had higher levels of perceived social support than the non pregnant adolescents (p=0.002). On the other hand, the adolescents no mothers showed a significant higher intelectual level than the adolescens mothers (p=0.017). The adolescent mothers didn’t show a higher level of depressive symptomatology than the adolescents non mothers. On the contrary, the adolescent non mothers showed significant higher levels of depressive symptomatology (p=0.032). The adolescent nonmothers didn’t had a significant higher level of self-steem than the adolescent mothers (p= 0.12). However, a weak significant differences was found in school self-steem (p=0.07) and in general self-steem (p= 0.09), the adolescents mothers having higher average than the adolescent non mothers. The findings invite us to think about cognitive development, particulary on the IQ and the personal narrative. The interaction of both factors leave the adolescents and their sons and daughters in a risky situation and vulnerability, important to consider it in future research and interventionsLa presente investigación analiza variables psicológicas asociadas a la maternidad de mujeres adolescentes menores de 15 años, comparándolas con madres entre 20 y 34 años y adolescentes no madres ni embarazadas, en un estudio de tipo transversal descriptivo comparativo. Las madres adultas no presentan niveles de apoyo social percibido significativamente mayores que las madres adolescentes menores de 15 años (p=0.46), así como tampoco un nivel intelectual significativamente mayor que las madres adolescentes menores de 15 años (p= 0.23). Además, no se observó un nivel de autoestima total significativamente mayor que las madres adolescentes menores de 15 años (p= 0.5). No obstante, las adolescentes madres evidencian significativamentemayor nivel de autoestima social que las madres adultas (p=0,036).Lasadolescentes no madres no presentaban un nivel de apoyo social  significativamente mayor que las adolescentes madres (p=0.49). Sin embargo, en la subescala amigos las adolescentes no madres presentaban significativamente mayor nivel de apoyo social percibido que las adolescentes madres (p=0,045) y en la subescala apoyo social percibido otros, las embarazadas adolescentes mostraron significativamente más apoyo social que las adolescentes no embarazadas (p=0,002). Por otra parte, las adolescentesno madres exhibieron un nivel intelectual significativamente mayor quelas adolescentes madres (p=0.017). Las adolescentes madres no evidenciaron un nivel de sintomatología depresiva significativamente mayor que las adolescentes no madres. Por el contrario estas últimas fueron las que mostraron, significativamente, un mayor nivel de sintomatología depresiva (p=0.032). Las adolescentes no madres no presentaron un nivel de autoestima significativamente mayor que las adolescentes madres (p= 0.12). Sin embargo, se observó diferencias débilmente significativas en las subescalas escolar (p=0,07) y general (p=0,099) a favor del grupo de madres adolescentes en relación al grupo de adolescentes no madres. Los resultados obtenidosinvitan a reflexionar acerca del rol del desarrollo cognitivo, en particular el coeficiente intelectual y la fábula personal. La conjugación de estos factores deja a las  menores y a su hijos/as en una situación de riesgo y vulnerabilidad, necesaria de atender en futuras investigaciones e intervenciones

Biomass partitioning and gas exchange parameters in different Musa cultivars as influenced by natural shade

Poster presented at Tropentag 2011 Development on the Margin. Bonn (Germany), 3-7 Oct 2011

The response of Musa cultivar root systems to a tree shade gradient

Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011

Two spatially separated phases in semiconducting Rb0.8_{0.8}Fe1.5_{1.5}S2_2

We report neutron scattering and transport measurements on semiconducting Rb$_{0.8}$Fe$_{1.5}$S$_2$, a compound isostructural and isoelectronic to the well-studied $A_{0.8}$Fe$_{y}$Se$_2 (A=$ K, Rb, Cs, Tl/K) superconducting systems. Both resistivity and DC susceptibility measurements reveal a magnetic phase transition at $T=275$ K. Neutron diffraction studies show that the 275 K transition originates from a phase with rhombic iron vacancy order which exhibits an in-plane stripe antiferromagnetic ordering below 275 K. In addition, interdigitated mesoscopically with the rhombic phase is an ubiquitous phase with $\sqrt{5}\times\sqrt{5}$ iron vacancy order. This phase has a magnetic transition at $T_N=425$ K and an iron vacancy order-disorder transition at $T_{S}=600$ K. These two different structural phases are closely similar to those observed in the isomorphous Se materials. Based on the close similarities of the in-plane antiferromagnetic structures, moments sizes, and ordering temperatures in semiconducting Rb$_{0.8}$Fe$_{1.5}$S$_2$ and K$_{0.81}$Fe$_{1.58}$Se$_2$, we argue that the in-plane antiferromagnetic order arises from strong coupling between local moments. Superconductivity, previously observed in the $A_{0.8}$Fe$_{y}$Se$_{2-z}$S$_z$ system, is absent in Rb$_{0.8}$Fe$_{1.5}$S$_2$, which has a semiconducting ground state. The implied relationship between stripe/block antiferromagnetism and superconductivity in these materials as well as a strategy for further investigation is discussed in this paper.Comment: 7 pages, 5 figure

Universal magnetic and structural behaviors in the iron arsenides

Commonalities among the order parameters of the ubiquitous antiferromagnetism present in the parent compounds of the iron arsenide high temperature superconductors are explored. Additionally, comparison is made between the well established two-dimensional Heisenberg-Ising magnet, K$_2$NiF$_4$ and iron arsenide systems residing at a critical point whose structural and magnetic phase transitions coincide. In particular, analysis is presented regarding two distinct classes of phase transition behavior reflected in the development of antiferromagnetic and structural order in the three main classes of iron arsenide superconductors. Two distinct universality classes are mirrored in their magnetic phase transitions which empirically are determined by the proximity of the coupled structural and magnetic phase transitions in these materials.Comment: 6 pages, 4 figure