Mean field study of structural changes in Pt isotopes with the Gogny interaction

The evolution of the nuclear shapes along the triaxial landscape is studied in the Pt isotopic chain using the selfconsistent Hartree-Fock-Bogoliubov approximation based on the Gogny interaction. In addition to the parametrization D1S, the new incarnations D1N and D1M of this force are also included in our analysis to asses to which extent the predictions are independent of details of the effective interaction. The considered range of neutron numbers 88<N<26 includes prolate, triaxial, oblate and spherical ground state shapes and serves for a detailed comparison of the predictions obtained with the new sets D1N and D1M against the ones provided by the standard parametrization Gogny-D1S in a region of the nuclear landscape for which experimental and theoretical fingerprints of shape transitions have been found. Structural evolution along the Pt chain is discussed in terms of the deformation dependence of single particle energies.Comment: 18 pages, 10 figures. Accepted for publication in Phys. Rev.

Quadrupole-octupole coupling and the onset of octupole deformation in actinides

The evolution of quadrupole and octupole collectivity and their coupling is investigated in a series of even-even isotopes of the actinide Ra, Th, U, Pu, Cm, and Cf with neutron number in the interval $130\leqslant N\leqslant 150$. The Hartree-Fock-Bogoliubov approximation, based on the parametrization D1M of the Gogny energy density functional, is employed to generate potential energy surfaces depending upon the axially-symmetric quadrupole and octupole shape degrees of freedom. The mean-field energy surface is then mapped onto the expectation value of the $sdf$ interacting-boson-model Hamiltonian in the boson condensate state as to determine the strength parameters of the boson Hamiltonian. Spectroscopic properties related to the octupole degree of freedom are produced by diagonalizing the mapped Hamiltonian. Calculated low-energy negative-parity spectra, $B(E3;3^{-}_{1}\to 0^{+}_{1})$ reduced transition rates, and effective octupole deformation suggest that the transition from nearly spherical to stable octupole-deformed, and to octupole vibrational states occurs systematically in the actinide region.Comment: 12 pages, 12 figure

Octupole correlations in light actinides from the interacting boson model based on the Gogny energy density functional

The quadrupole-octupole coupling and the related spectroscopic properties have been studied for the even-even light actinides $^{218-238}$Ra and $^{220-240}$Th. The Hartree-Fock-Bogoliubov approximation, based on the Gogny-D1M energy density functional, has been employed as a microscopic input, i.e., to obtain (axially symmetric) mean-field potential energy surfaces as functions of the quadrupole and octupole deformation parameters. The mean-field potential energy surfaces have been mapped onto the corresponding bosonic potential energy surfaces using the expectation value of the $sdf$ Interacting Boson Model (IBM) Hamiltonian in the boson condensate state. The strength parameters of the $sdf$-IBM Hamiltonian have been determined via this mapping procedure. The diagonalization of the mapped IBM Hamiltonian provides energies for positive- and negative-parity states as well as wave functions which are employed to obtain transitional strengths. The results of the calculations compare well with available data from Coulomb excitation experiments and point towards a pronounced octupole collectivity around $^{224}$Ra and $^{226}$Th.Comment: 15 pages, 10 figures, 1 tabl

La medicina y la enfermedad en Alfonso Reyes

En este ensayo se analizan los síntomas, las enfermedades y las terapias que sufrió el escritor mexicano Alfonso Reyes, reconocido como uno de los escritores más importantes de habla hispana. Se revisa su biografía, que muestra la evolución de sus síntomas cardiovasculares y se documentan las patologías principales que tuvo a lo largo de su vida. Algunas de las enfermedades que sufrió Alfonso Reyes influyeron en su creación literaria, y su condición de enfermo constante lo llevó a reflexiones nada casuales, siendo un ejemplar paciente. Abstract: In this essay, the symptoms, diseases and therapies that the Mexican writer Alfonso Reyes suffered are analyzed. In addition, his biography is reviewed, which shows the evolution of his cardiovascular symptoms and the main diseases and surgeries that he had throughout his life. The diseases suffered by Alfonso Reyes influenced his literary creation and, because of his constant diseases, he made very non-casual l reflections. He was also an exemplary patient

Imatinib therapy of chronic myeloid leukemia restores the expression levels of key genes for DNA damage and cell-cycle progression

[EN] Background Chronic myeloid leukemia (CML) is a malignant clonal disorder of the hematopoietic system caused by the expression of the BCR/ABL fusion oncogene. It is well known that CML cells are genetically unstable. However, the mechanisms by which these cells acquire genetic alterations are poorly understood. Imatinib mesylate is the standard therapy for newly diagnosed CML patients. Imatinib mesylate targets the oncogenic kinase activity of BCR-ABL. Objective To study the gene expression profile of bone marrow hematopoietic cells in the same patients with CML before and 1 month after imatinib therapy. Methods Samples from patients with CML were analyzed using Affymetrix GeneChip Expression Arrays. Results A total of 594 differentially expressed genes, most of which (393 genes) were downregulated, as a result of imatinib therapy were observed. Conclusion The blockade of oncoprotein Bcr-Abl by imatinib could cause a decrease in the expression of key DNA repair genes and substantially modify the expression profile of the bone marrow cells in the first days of therapy

Measuring color differences in gonioapparent materials used in the automotive industry

This paper illustrates how to design a visual experiment to measure color differences in gonioapparent materials and how to assess the merits of different advanced color-difference formulas trying to predict the results of such experiment. Successful color-difference formulas are necessary for industrial quality control and artificial color-vision applications. A color- difference formula must be accurate under a wide variety of experimental conditions including the use of challenging materials like, for example, gonioapparent samples. Improving the experimental design in a previous paper [Melgosaet al., Optics Express 22, 3458-3467 (2014)], we have tested 11 advanced color-difference formulas from visual assessments performed by a panel of 11 observers with normal colorvision using a set of 56 nearly achromatic colorpairs of automotive gonioapparent samples. Best predictions of our experimental results were found for the AUDI2000 color-difference formula, followed by color-difference formulas based on the color appearance model CIECAM02. Parameters in the original weighting function for lightness in the AUDI2000 formula were optimized obtaining small improvements. However, a power function from results provided by the AUDI2000 formula considerably improved results, producing values close to the inter-observer variability in our visual experiment. Additional research is required to obtain a modified AUDI2000 color-difference formula significantly better than the current one.This research was supported by the Ministry of Economy and Competitiveness of Spain, research projects FIS2013-40661-P and DPI2011-30090-C02, with European Research Development Fund (ERDF), as well as by the National Science Foundation of China (grant number 61178053)

The Zoning of Semi-Enclosed Bodies of Water According to the Sediment Pollution: The Bay of Algeciras as a Case Example

This paper reports a study of the occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in a bay characterised by a chronic persistent impact. A total of 55 sediment samples were taken at different depths up to 111 m in two sampling campaigns. Chemical analyses were carried out by gas chromatography-mass spectroscopy. The results indicate that: (1) significant spatial variations exist, (2) levels of PAHs are related more strongly to the spatial distribution of sediments than to mineralogy/granulometry, (3) the sediments are slightly-to-moderately contaminated by PAHs, and (4) these PAHs derive from pyrolytic and petrogenic sources. Through use of an innovative data classification system (proposed according to depth and spatial location of sampling points), and using factorial and cluster techniques, five zones have been differentiated depending on the contamination level and source

Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR