Evolution of elastic thin films with curvature regularization via minimizing movements

The evolution equation with curvature regularization that models the motion of a two-dimensional thin film by evaporation-condensation on a rigid substrate is considered. The film is strained due to the mismatch between the crystalline lattices of the two materials. Here, short time existence, uniqueness and regularity of the solution are established using De Giorgi’s minimizing movements to exploit the $L^{2}$ -gradient flow structure of the equation. This seems to be the first analytical result for the evaporation-condensation case in the presence of elasticity.     

New diterpenoids from Calceolaria polifolia

Four new and seven known diterpenes have been isolated from the dichloromethane extract of the aerial parts of Calceolaria polifolia. The structures of the new compounds were established by spectroscopic evidence.     

Crystalline and Isoperimetric Square Configurations

We present crystallization results for planar atomic interactions governed by two- and three-body terms with the resulting periodicity being that of the square lattice. The emergence of a (square) Wulff shape for ground states is established by showing the optimality of ground-state configurations in terms of a discrete isoperimetric inequality. Furthermore, an n^3/4 law for the deviation from the asymptotic Wulff shape is established with an explicit constant for the leading term. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

$$N^{3/4}$$ N 3 / 4 Law in the Cubic Lattice

Journal of Statistical Physics - We investigate the Edge-Isoperimetric Problem (EIP) for sets with n elements of the cubic lattice by emphasizing its relation with the emergence of the Wulff shape...     

Determination of antioxidant properties of 26 Chilean honeys and a mathematical association study with their volatile profile

Radical scavenging activity (RSA), antioxidant content (TEAC), total phenolic compounds content (TPCC) and volatile profile (VOCs) were measured in 26 honeys obtained from the Valparaiso Region (Chile). Persea americana honey was the most interesting sample according to these evaluated parameters. A Projection to Latent Structures (PLS) based algorithm was used to model the possible relationship between antioxidant activity, total phenolic compounds content and volatile profile. Concerning the volatile profile, only nine volatile compounds, of a total of fifty, showed dependence on antioxidant activity and total phenolic compounds content.     

Synchrotron study of oxygen depletion in a Bi‐2212 whisker annealed at 363 K

Direct evidence is reported of structural and electronic effects induced on a single Bi₂Sr₂CaCu₂O_8+δ (Bi‐2212) whisker during a progressive annealing process. The crystal was investigated by micro X‐ray diffraction (µ‐XRD), micro X‐ray fluorescence and electrical characterization at the European Synchrotron Radiation Facility, during a series of three in situ thermal processes at 363 K. Each step increased the sample resistivity and decreased its critical temperature, up to a semiconducting behaviour. These data correlate with µ‐XRD analysis, which shows an increase of the c‐axis parameter from 30.56 Å to 30.75 Å, indicating an oxygen depletion mechanism. Mild temperature annealing could be an effective process to modulate the intrinsic Josephson junctions' characteristics in Bi‐2212 whiskers.     

Rare earth element patterns in lake sediments as studied by neutron activation analysis

Using instrumental neutron activation analysis, the vertical distribution of La, Ce, Nd, Sm, Eu, Tb, Yb and Lu was determined in 3 well dated sedimentary cores collected from Laguna Mar Chiquita, Argentina. Validation of the methodology was done using the Soil 7 (IAEA) reference material. The REE contents vary according to core location and lithological units, depending on the proportion of fluvial terrigenous components in the lake sediments. Lithologies with higher proportion of terrigenous components show higher REE concentrations, suggesting that the dominant REE carrier phase might be a detrital mineral. There is a consistent value of about 1.2 for (La/Yb)_N and (LREE/HREE)_N ratios for all sediments at the three sites, indicating a slight LREE enrichment in relation to the average shale NASC. Ce/Ce* values are close to 1.0, meaning that Ce behaves similarly to other light REE's.     

Diterpenoids from Calceolaria alba

Chemical examination of the petrol ether (60-80) extract of the aerial parts of Calceolaria alba R. et Pav., collected in Santa Juana, VIII Region, Chile, resulted in the isolation of 3 new diterpenoids. Their structures have been elucidated by a study of their physical and spectral data; in particular using 2 NMR spectroscopy (DEPT, 1H-1H, COSY, NOESY, HMQC and HMBC).     

Neutron investigations of the magnetic properties of Fe<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>S under pressure up to 4.2 GPa

Fe _x Mn_1?x S belongs to the group of strong electron correlations compounds MnO. We present here experimental results for the antiferromagnetic iron–manganese sulfide system, based on X-ray and neutron diffraction studies. The neutron diffraction investigations were carried out at ambient conditions and at hydrostatic pressures up to 4.2 GPa in the temperature range from 65 to 300 K. Our results indicate that the Néel temperature of α-MnS increases up to room temperature by applying chemical (x _Fe) or weak hydrostatic pressure P. In Fe_0.27Mn_0.73S, the Néel temperature increases from 205(2) K (P = 0 GPa) to 280(2) K (P = 4.2 GPa) and the magnetization at 100 K decreases by a factor of 2.5 when the hydrostatic pressure increases from 0 to 4.2 GPa.     

Multielemental determination by instrumental neutron activation analysis and recent sedimentation rates using 210 Pb dating method at Laguna del Plata, Cordoba, Argentina

Laguna del Plata (Cordoba, Argentina) is a small saline lake connectedto Laguna Mar Chiquita. Its level fluctuations have changed notably throughthe centuries with both high level (HLP) and low level (LLP) periods. Theradionuclides 226 Ra and 210 Pb were analyzed in a core to determine datesand sedimentation rates. The elements As, Ba, Br, Co, Cr, Cs, Fe, Hf, Na,Rb, Sb, Sc, Se, Ta, Th, U, Zn, Zr and rare earth Ce, Eu, La, Lu, Nd, Sm, Tband Yb were determined by instrumental neutron activation analysis. Statisticalanalysis of elemental concentrations (cluster analysis) reflects the associationof the samples along the core according to the provenance of the sedimentsand if they had been deposited during HLP or LLP.