A Sensitivity Analysis for Quality Measures of Quantitative Association Rules

There exist several fitness function proposals based on a combination of weighted objectives to optimize the discovery of association rules. Nevertheless, some differences in the measures used to assess the quality of association rules could be obtained according to the values of such weights. Therefore, in such proposals it is very important the user’s decision in order to specify the weights or coefficients of the optimized objectives. Thus, this work presents an analysis on the sensitivity of several quality measures when the weights included in the fitness function of the existing QARGA algorithm are modified. Finally, a comparative analysis of the results obtained according to the weights setup is provided.MICYT TIN2011-28956-C02-00Junta de Andalucía P11-TIC-752

Intrinsic Localized Modes Observed in the High Temperature Vibrational Spectrum of NaI

Inelastic neutron measurements of the high-temperature lattice excitations in NaI show that in thermal equilibrium at 555 K an intrinsic mode, localized in three dimensions, occurs at a single frequency near the center of the spectral phonon gap, polarized along [111]. At higher temperatures the intrinsic localized mode gains intensity. Higher energy inelastic neutron and x-ray scattering measurements on a room-temperature NaI crystal indicate that the creation energy of the ground state of the intrinsic localized mode is 299 meV.Comment: 17 pages, 5 figures Revised version; final versio

Influence of Magnetism on Phonons in CaFe2As2 Via Inelastic X-ray Scattering

In the iron pnictides, the strong sensitivity of the iron magnetic moment to the arsenic position suggests a significant relationship between phonons and magnetism. We measured the phonon dispersion of several branches in the high temperature tetragonal phase of CaFe2As2 using inelastic x-ray scattering on single-crystal samples. These measurements were compared to ab initio calculations of the phonons. Spin polarized calculations imposing the antiferromagnetic order present in the low temperature orthorhombic phase dramatically improve agreement between theory and experiment. This is discussed in terms of the strong antiferromagnetic correlations that are known to persist in the tetragonal phase.Comment: 4 pages, 3 figures; added additional information and references about spin fluctuation

Observation of a continuous phase transition in a shape-memory alloy

Elastic neutron-scattering, inelastic x-ray scattering, specific-heat, and pressure-dependent electrical transport measurements have been made on single crystals of AuZn and Au_{0.52}Zn_{0.48} above and below their martensitic transition temperatures (T_M=64K and 45K, respectively). In each composition, elastic neutron scattering detects new commensurate Bragg peaks (modulation) appearing at Q = (1.33,0.67,0) at temperatures corresponding to each sample's T_M. Although the new Bragg peaks appear in a discontinuous manner in the Au_{0.52}Zn_{0.48} sample, they appear in a continuous manner in AuZn. Surprising us, the temperature dependence of the AuZn Bragg peak intensity and the specific-heat jump near the transition temperature are in favorable accord with a mean-field approximation. A Landau-theory-based fit to the pressure dependence of the transition temperature suggests the presence of a critical endpoint in the AuZn phase diagram located at T_M*=2.7K and p*=3.1GPa, with a quantum saturation temperature \theta_s=48.3 +/- 3.7K.Comment: 6 figure

The Relationship between Expression of p70s6k with Radiotherapy Response in Cervical Cancer

There are many important prognostic factors in advanced stage cervical cancer primary treated with radiotherapy. Besides clinical factors, many biomarkers have been studied in relation with radiotherapy response. The p70s6k is a biomarker which plays a significant role in cell proliferation. Increased levels of p70s6k are also associated with drug resistance in cancer. In the present study, the relationship between the expression level of p70s6k before treatment and the radiotherapy response in cervical cancer was determined. Immunohistochemical staining of p70s6k, MIB-1, and p53 was conducted in microscopic slide from 21 cancer tissue biopsies before treatment with radiotherapy. After the treatment had completed early radiotherapy response was observed by pelvic control method. The results showed that p70s6k is partly highly expressed (61.9%, 13/21) and partly low expressed (38.1%, 8/21) in the cancer cells. They also show that there is no statistically significant differences on AgNOR mean, MIB-1, and p53 indices in the different degrees of p70s6k expression (p≥0.05). Higher expression levels of p70s6k is more strongly associated with good radiotherapy response compared to lower ones (p=0.05). In conclusion, the level of p70s6k expression before treatment has an association with radiotherapy response

Active Creation of Instrinsically Localized Vibrations in Uranium Using X-Ray and Neutron Scattering

In real materials, nonlinear forces cause the frequencies of vibrating atoms to depend on amplitude. As a consequence, a large-amplitude fluctuation on the scale of the atom spacing can develop a frequency that does not resonate with the normal modes, causing energy to become trapped in an intrinsically localized mode (ILM)--also called 'discrete breather' or 'lattice soliton'. As temperature is increased, entropy is expected to stabilize increased concentrations of these random hotspots. This mechanism, which spontaneously concentrates energy, has been observed in analogous systems on a larger scale, but direct sightings at the atomic scale have proved difficult. Two challenges have hampered progress: (1) the need to separate ILMs from modes associated with crystal imperfections, and (2) complications that arise at high temperatures, including feature broadening and multiphonon processes. Here we solve both of these problems by actively creating ILMs at low temperatures in {alpha}-uranium using high-energy inelastic x-ray and neutron scattering. The ILM creation excitation occurs at energies ten times higher than conventional lattice excitations, cleanly separating it from modes associated with crystal imperfections. The discovery of this excitation not only proves the existence of ILMs in uranium but also opens up a new route for finding ILMs in other materials and, in the process, a new area for spectroscopy