Solving Lattice QCD systems of equations using mixed precision solvers on GPUs

Modern graphics hardware is designed for highly parallel numerical tasks and promises significant cost and performance benefits for many scientific applications. One such application is lattice quantum chromodyamics (lattice QCD), where the main computational challenge is to efficiently solve the discretized Dirac equation in the presence of an SU(3) gauge field. Using NVIDIA's CUDA platform we have implemented a Wilson-Dirac sparse matrix-vector product that performs at up to 40 Gflops, 135 Gflops and 212 Gflops for double, single and half precision respectively on NVIDIA's GeForce GTX 280 GPU. We have developed a new mixed precision approach for Krylov solvers using reliable updates which allows for full double precision accuracy while using only single or half precision arithmetic for the bulk of the computation. The resulting BiCGstab and CG solvers run in excess of 100 Gflops and, in terms of iterations until convergence, perform better than the usual defect-correction approach for mixed precision.Comment: 30 pages, 7 figure

Atherogenic lipid profile of Brazilian near-term newborns

Cardiovascular disease is the primary cause of death in Brazil. Recent studies have shown that low birth weight and preterm birth are linked to a higher prevalence of cardiovascular disease. The aim of the present study was to compare the levels of lipids and apolipoproteins and atherogenic indexes between term and near-term newborn infants. A sample of umbilical cord blood was obtained from 135 newborns (66 males) divided into two groups: 25 near-term neonates (35-36.6 weeks of gestational age) and 110 term neonates (37-42 weeks of gestational age). The total cholesterol concentrations were higher in the near-term neonates than in the term group (94.04 ± 8.02 vs 70.42 ± 1.63 mg/dl, P < 0.01), due to an increase in the LDL-cholesterol fraction in the near-term group (57.76 ± 6.39 vs 34.38 ± 1.29 mg/dl, P < 0.001). The atherogenic indexes (total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol and apolipoprotein B/apolipoprotein A-I) were higher in the near-term group (P < 0.001, P < 0.001, and P < 0.05, respectively). The gestational age of the newborns was inversely correlated with total cholesterol and LDL-cholesterol, and also with the total cholesterol/HDL-cholesterol and LDL-cholesterol/HDL-cholesterol indexes. These findings demonstrate that the lipid profile is worse in the group of near-term neonates compared with the term group. Future studies are needed to determine if this atherogenic profile in near-term neonates can affect body metabolism, increasing the risk for cardiovascular diseases in adult life.75576

The Causal Interpretation of Dust and Radiation Fluids Non-Singular Quantum Cosmologies

We apply the causal interpretation of quantum mechanics to homogeneous and isotropic quantum cosmology where the sources of the gravitational field are either dust or radiation perfect fluids. We find non-singular quantum trajectories which tends to the classical one when the scale factor becomes much larger then the Planck length. In this situation, the quantum potential becomes negligible. There are no horizons. As radiation is a good approximation for the matter content of the early universe, this result suggests that the universe can be eternal due to quantum effects.Comment: 10 pages, LaTeX, 5 figures in postscript, requires eps

La ciencia andaluza a golpe de ratón

El Sistema de Información Científica de Andalucía (SICA) es una ventana al conocimiento que se produce en nuestra comunidad autónoma. En 2010 ha comenzado el diseño de SICA2 que situará a esta plataforma en la vanguardia de la sistematización y la difusión de la investigació

Stevia rebaudiana Bertoni cultivated in Portugal: a prospective study of its antioxidant potential in different conservation conditions

Studies with well-established cultivation conditions are of utmost importance in order to standardize the plants production and, therefore, its chemical composition. However, the conservation conditions may influence some of the bioactive compounds present in those plants. Stevia rebaudiana Bertoni samples cultivated in the north-eastern of Portugal, were exposed to different conservation conditions (oven-dried at 30 °C, for six days, or kept fresh by freezing (-20 °C) in the same period), and then studied for their antioxidant potential (including antioxidant compounds such as reducing sugars, tocopherols and phenolic compounds, free radical scavenging activity (DPPH) and reducing power (RP)). Oven-dried samples gave the highest antioxidant activity (DPPH EC50 = 22.87 µg/mL and RP EC50 = 28.79 µg/mL) and the highest total phenolic compounds concentration. The most abundant phenolic compounds in both samples were two caffeic acid derivatives, 5-O-caffeoylquinic acid (chlorogenic acid) and 3,5-O-dicaffeoylquinic acid. Otherwise, the highest values of total tocopherols and total sugars were registered in frozen fresh samples. This study gives clues to choose the most appropriate methodology to preserve primary or secondary metabolites of S. rebaudiana, involved in its antioxidant activity.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programe PT2020 for financial support to CIMO (UID/AGR/00690/2013), LSRE (Project UID/EQU/50020/2013) and L. Barros (SFRH/BPD/107855/2015) grant

Impact of food eviction on the nutritional status and adequacy of nutritional intake on children with food allergy

[resumo][abstract

Relation of fibrocartilaginous embolism and acute and non-compressive nucleus pulposus extrusion with imaging tests - case report

ABSTRACT Fibrocartilaginous embolism (FCEM) and acute, non-compressive nucleus pulposus extrusion (ANNPE) are non-compressive myelopathies that are difficult to differentiate. The definitive diagnosis is obtained only with histology, but the presumptive diagnosis is made through clinical signs and imaging tests. The aim of this study is to report the imaging tests performed for the diagnosis of a neurological clinical case and discuss the best diagnostic method. After attending the patient, complementary tests were requested. Radiography results showed no change. The computed tomography diagnostic impression indicated distal protrusion between C6-C7, T11-T12, T13-L1 followed by mild spinal cord compression defined by the presence of a ventral hyperattenuating region. Magnetic resonance (RMI), showed a slight T2W hypersignal, well delimited in the gray matter, lateralized to the right, over the cranial third of C7. Concluding that the magnetic resonance is the method that brought more information for the diagnosis, in which the others were not described medullary alterations pertinent to FCEM and ANNPE. With their fair prognosis, the absence of histological diagnosis of these diseases may be a limiting factor in this study and, in relation to the RMI alterations being very similar between FCEM and ANNPE it is not possible to diagnose fully accurately

Assessment of the nitrogen fertilization effect on bioactive compounds of frozen fresh and dried samples of Stevia rebaudiana Bertoni

The present study aims to assess the effect of different nitrogen (N) rates on the chemical composition and antioxidant properties of stevia frozen fresh and dried leaves, and to define the best growing conditions to maximize the levels of bioactive compounds. In general, processing affects more significantly the tocopherol and sugar contents than N fertilization. The most abundant sugars were xylose, arabinose + fructose and sucrose, presenting dried samples with higher contents than frozen fresh ones, while the latter better retained tocopherols than dry samples. Regarding phenolic compounds, greater levels were found in dried samples and in those fertilized with 25 kg N ha −1 . Leaves from plants fertilized with 25 and 50 kg N ha −1 also evidenced higher antioxidant activity, which seemed to be influenced by the phenolic composition. In general, N fertilization provides an improvement in the chemical composition and bioactive potential of stevia leaves.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and to L. Barros contract. The authors are also grateful to the Interreg España-Portugal for financial support through the project 0377_Iberphenol_6_E. The GIP-USAL is financially supported by the Spanish Government through the project AGL2015-64522-C2-2-R.info:eu-repo/semantics/publishedVersio