Frustration driven structural distortion in VOMoO4

Nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), magnetization measurements and electronic structure calculations in VOMoO4 are presented. It is found that VOMoO4 is a frustrated two-dimensional antiferromagnet on a square lattice with competing exchange interactions along the side J1 and the diagonal J2 of the square. From magnetization measurements J1+J2 is estimated around 155 K, in satisfactory agreement with the values derived from electronic structure calculations. Around 100 K a structural distortion, possibly driven by the frustration, is evidenced. This distortion induces significant modifications in the NMR and EPR spectra which can be accounted for by valence fluctuations. The analysis of the spectra suggests that the size of the domains where the lattice is distorted progressively grows as the temperature approaches the transition to the magnetic ground state at Tc=42 K

Cómo afecta la integración internacional a las exportaciones de los estados brasileños

Este trabajo busca determinar los impactos de la integración internacional en la exportación de los estados brasileños. Utilizamos un modelo gravitacional con variables dummy para los bloques principales de comercio y para cada región brasileña. Variables que capturan la apertura y la competitividad regionales también se incluyen. Estimamos un modelo de pooled cross-section, con datos para 2 países, 27 estados, y años. Controlando para el tamaño y la distancia, el comercio con MERCOSUR y la UE es más intenso que con el resto del mundo. Los estados brasileños que abarcan partes más grandes del comercio interregional total tienden a negociar menos internacionalmente, mientras que lo contrario se sostiene para los que sean más competitivos. Los resultados también indican que las especificidades sectoriales desempeñan un papel en explicar las exportaciones del estado, como en el caso de la agricultura. ____________________________________________This paper assesses the impacts of international integration on the export flows of Brazilian states. We use a gravity model with dummy variables for the main partner blocs and for each pair Brazilian region-partner country, to account for the specificities of particular trade relations. Variables capturing regional openness and competitiveness are also included. We estimate a pooled cross-section model, with data for 2 countries, 27 states, and years. After controlling for size and distance, trade with Mercosur and the EU is more intense than with the rest of the world. States accounting for larger shares of interregional trade tend to trade less internationally, while the opposite holds for those that are more competitive. The results also indicate that sectoral specificities play a role in explaining state’s exports, as in the case of agriculture

Atmospheric nitrogen deposition in a highly human impacted area in northern Italy

Nitrogen can enter the water cycle through atmospheric depositions on ground and water surfaces, leakages from point and diffuse sources (i.e., sewage treatment plants or sewage systems, fertilizer and manure applications), and erosion processes affecting nitrogen rich soils (EEA, 2005). However, integrating all nitrogen forms, processes and scales is still a major challenge for the understanding and the management of the nitrogen cycle

Mesoscopic phase separation in Nax_xCoO2_2 (0.65≤x≤0.750.65\leq x\leq 0.75)

NMR, EPR and magnetization measurements in Na$_x$CoO$_2$ for $0.65\leq x\leq 0.75$ are presented. While the EPR signal arises from Co$^{4+}$ magnetic moments ordering at $T_c\simeq 26$ K, $^{59}$Co NMR signal originates from cobalt nuclei in metallic regions with no long range magnetic order and characterized by a generalized susceptibility typical of strongly correlated metallic systems. This phase separation in metallic and magnetic insulating regions is argued to occur below $T^*(x)$ ($220 - 270$ K). Above $T^*$ an anomalous decrease in the intensity of the EPR signal is observed and associated with the delocalization of the electrons which for $T<T^*$ were localized on Co$^{4+}$ $d_{z^2}$ orbitals. It is pointed out that the in-plane antiferromagnetic coupling $J\ll T^*$ cannot be the driving force for the phase separation.Comment: 14 figure

Recent structural evolution of forni glacier tongue (Ortles-Cevedale Group, Central Italian Alps)

Structural glaciology yields important details about the evolution of glacier dynamics in response to climate change. The maps provided here document the occurrence and evolution of brittle and ductile structures on the tongue of Forni Glacier, Ortles-Cevedale Group, Central Italian Alps, between 2003 and 2014. Through the remote sensing-based analysis of structures, we found evidence of brittle fractures such as crevasses, faults and ring faults, and ductile structures such as ogives at the base of the icefall in the eastern glacier tongue. Although each of the three glacier tongues have evolved differently, a reduction in flow-related dynamics and an increase in the number of collapse structures occurred over the study period. Analysis of the glacier structural evolution based on the numbers and the locations of different structures, suggest a slowdown of glacier flow on the eastern tongue. The recent evolution of the glacier also suggests that the occurrence of a disintegration scenario is likely to worsen over the next decades

Tree-Based Methods for Discovery of Association between Flow Cytometry Data and Clinical Endpoints

We demonstrate the application and comparative interpretations of three tree-based algorithms for the analysis of data arising from flow cytometry: classification and regression trees (CARTs), random forests (RFs), and logic regression (LR). Specifically, we consider the question of what best predicts CD4 T-cell recovery in HIV-1 infected persons starting antiretroviral therapy with CD4 count between 200 and 350 cell/μL. A comparison to a more standard contingency table analysis is provided. While contingency table analysis and RFs provide information on the importance of each potential predictor variable, CART and LR offer additional insight into the combinations of variables that together are predictive of the outcome. In all cases considered, baseline CD3-DR-CD56+CD16+ emerges as an important predictor variable, while the tree-based approaches identify additional variables as potentially informative. Application of tree-based methods to our data suggests that a combination of baseline immune activation states, with emphasis on CD8 T-cell activation, may be a better predictor than any single T-cell/innate cell subset analyzed. Taken together, we show that tree-based methods can be successfully applied to flow cytometry data to better inform and discover associations that may not emerge in the context of a univariate analysis