Automatic Differentiation Tools in Optimization Software

We discuss the role of automatic differentiation tools in optimization software. We emphasize issues that are important to large-scale optimization and that have proved useful in the installation of nonlinear solvers in the NEOS Server. Our discussion centers on the computation of the gradient and Hessian matrix for partially separable functions and shows that the gradient and Hessian matrix can be computed with guaranteed bounds in time and memory requirementsComment: 11 page

Computing Heavy Elements

Reliable calculations of the structure of heavy elements are crucial to address fundamental science questions such as the origin of the elements in the universe. Applications relevant for energy production, medicine, or national security also rely on theoretical predictions of basic properties of atomic nuclei. Heavy elements are best described within the nuclear density functional theory (DFT) and its various extensions. While relatively mature, DFT has never been implemented in its full power, as it relies on a very large number (~ 10^9-10^12) of expensive calculations (~ day). The advent of leadership-class computers, as well as dedicated large-scale collaborative efforts such as the SciDAC 2 UNEDF project, have dramatically changed the field. This article gives an overview of the various computational challenges related to the nuclear DFT, as well as some of the recent achievements.Comment: Proceeding of the Invited Talk given at the SciDAC 2011 conference, Jul. 10-15, 2011, Denver, C

Morphological and Molecular Characteristics of <i>Sarcocystis aucheniae</i> Isolated from Meat of Guanaco (<i>Lama guanicoe</i>)

Background: Sarcocystosis in South American camelids (SAC) is an important parasitic disease which results in economical loss due to carcass condemnation. Meat products from camelids are significant source of animal protein in several American countries. Sarcocystis spp. producing macroscopical cysts in these animals have been nominated as S. aucheniae, S. tilopodi, and S. guanicoecanis. The aim of the present study was to characterize morphologically and molecularly Sarcocystis spp. producing macroscopical cysts in guanacos (Lama guanicoe). Methods: Samples of macroscopical cysts were dissected from guanaco muscles slaughtered in Santa Cruz province, Argentina. The samples were processed by transmission electron microscopy, polymerase chain reaction (PCR), cloning and sequencing studies. Results: Cyst wall villar protrusions were irregular with a “tree” or “cauliflower-like” shape which measured 3-4.5 µm height by 2.5-3.5 µm width. A consensus 18S rRNA full gene sequence of 1875 bp was obtained and showed the highest identity (≥ 99 %) with sequences of S. aucheniae reported in GenBank. The ultra structure of the cyst wall from macroscopical cysts and 18S rRNA gene obtained from guanacos were identical and consistent with the descriptions of S. aucheniae. Conclusion: This study confirms that guanacos are infected by the same Sarcocystis spp. affecting other SAC, named S. aucheniae, and reinforce the suggestion that nomination of new species should contain morphological and molecular data to reach validity. In future, this data could be useful to obtain proper identifications in post-mortem inspection and helpful to improve meat safety.Facultad de Ciencias Veterinaria

Morphological and Molecular Characteristics of <i>Sarcocystis aucheniae</i> Isolated from Meat of Guanaco (<i>Lama guanicoe</i>)

Background: Sarcocystosis in South American camelids (SAC) is an important parasitic disease which results in economical loss due to carcass condemnation. Meat products from camelids are significant source of animal protein in several American countries. Sarcocystis spp. producing macroscopical cysts in these animals have been nominated as S. aucheniae, S. tilopodi, and S. guanicoecanis. The aim of the present study was to characterize morphologically and molecularly Sarcocystis spp. producing macroscopical cysts in guanacos (Lama guanicoe). Methods: Samples of macroscopical cysts were dissected from guanaco muscles slaughtered in Santa Cruz province, Argentina. The samples were processed by transmission electron microscopy, polymerase chain reaction (PCR), cloning and sequencing studies. Results: Cyst wall villar protrusions were irregular with a “tree” or “cauliflower-like” shape which measured 3-4.5 µm height by 2.5-3.5 µm width. A consensus 18S rRNA full gene sequence of 1875 bp was obtained and showed the highest identity (≥ 99 %) with sequences of S. aucheniae reported in GenBank. The ultra structure of the cyst wall from macroscopical cysts and 18S rRNA gene obtained from guanacos were identical and consistent with the descriptions of S. aucheniae. Conclusion: This study confirms that guanacos are infected by the same Sarcocystis spp. affecting other SAC, named S. aucheniae, and reinforce the suggestion that nomination of new species should contain morphological and molecular data to reach validity. In future, this data could be useful to obtain proper identifications in post-mortem inspection and helpful to improve meat safety.Facultad de Ciencias Veterinaria

Spanish validation of the revised depression attitude questionnaire (R-daq)

Purpose: The aim of the study was to develop and validate a Spanish version of the Revised Depression Attitude Questionnaire (R-DAQ). Methods: The R-DAQ was used as a baseline for the study. It was translated and tested to ensure the instrument was appropriate for the target population. 537 Ecuadorian healthcare professionals completed the revised Spanish version of the R-DAQ (SR-DAQ). Statistical and exploratory factor analyses were performed to examine construct validity, internal consistency, readability and floor and ceiling effects. Results: Three factors were obtained: “Professional confidence in depression care”; “Therapeutic optimism about depression”; and “Generalist perspective about depression occurrence, recognition, and management”. The internal consistency of the SR-DAQ was determined by means of Cronbach’s α coefficient, with values ranging between 0.61–0.8. The correlations with the English version reflected adequate validity. The model explained 39% of the variance. Subsequent analysis with a sample restricted to those who had received training in depression produced a model that explained 42% of the variance. Conclusion: The SR-DAQ meets the psychometric requirements for measuring depression attitude in a Spanish-speaking population and shows adequate internal consistency and validity

Hydrogen bonding in infinite hydrogen fluoride and hydrogen chloride chains

Hydrogen bonding in infinite HF and HCl bent (zigzag) chains is studied using the ab initio coupled-cluster singles and doubles (CCSD) correlation method. The correlation contribution to the binding energy is decomposed in terms of nonadditive many-body interactions between the monomers in the chains, the so-called energy increments. Van der Waals constants for the two-body dispersion interaction between distant monomers in the infinite chains are extracted from this decomposition. They allow a partitioning of the correlation contribution to the binding energy into short- and long-range terms. This finding affords a significant reduction in the computational effort of ab initio calculations for solids as only the short-range part requires a sophisticated treatment whereas the long-range part can be summed immediately to infinite distances.Comment: 9 pages, 4 figures, 3 tables, RevTeX4, corrected typo