Parallel implementation for large and sparse eigenproblems

This paper analyses and evaluates the computational aspects of an efficient parallel implementation for the eigenproblem. This parallel implementation allows to solve the eigenproblem of symmetric, sparse and very large matrices. Mathematically, the algorithm is supported by the Lanczos and Divide and Conquer methods. The Lanczos method transforms the eigenproblem of a symmetric matrix into an eigenproblem of a tridiagonal matrix which is easier to be solved. The Divide and Conquer method provides the solution for the eigenproblem of a large tridiagonal matrix by decomposing it in a set of smaller subproblems. The method has been implemented for a distributed memory multiprocessor system with the PVM parallel interface. A Cray T3E system with up to 32 nodes has been used to evaluate the performance of our parallel implementation. Due to the super-lineal speed-up values obtained for all the studied matrices, a detailed analysis of the experimental results is carried out. It will be shown that the management of the memory hierarchy plays an important role in the performance of the parallel implementation

Predictive modelling of magnesium concentration in grapevine petioles as a basis for liming recommendations in vineyard acid soils

Soil acidification is a natural process which can either be accelerated by the activity of plants, animals and humans, but can be controlled through appropriate soil management. The main aim of this work was to develop a predictive modelling of magnesium concentration in grapevine petioles for liming amendment recommendation in vineyard acid soils. One liming material, dolomite, has been added to the soil at three doses: 0.9, 1.8 and 2.7 t CaCO3 ha-1. Magnesium exchangeable content in soil surface and concentrations of this nutrient in petioles of leaf samples were investigated during three years. Exchangeable magnesium in soil tended to increase with increasing dolomite application rate. These increases were significant among all the doses and the control, except for the dose of 0.9. However, only between the highest dose and the control significant differences in magnesium concentration in petioles could be detected. In addition, one linear model has been proposed to make liming recommendations in vineyard acid soils based on petiole magnesium concentrations.

Chirality in Bare and Passivated Gold Nanoclusters

Chiral structures have been found as the lowest-energy isomers of bare (Au$_{28}$ and Au$_{55}) and thiol-passivated (Au$_{28}(SCH$_{3})$_{16}$and Au$_{38}(SCH_{3})_{24}) gold nanoclusters. The degree of chirality existing in the chiral clusters was calculated using the Hausdorff chirality measure. We found that the index of chirality is higher in the passivated clusters and decreases with the cluster size. These results are consistent with the observed chiroptical activity recently reported for glutahione-passivated gold nanoclusters, and provide theoretical support for the existence of chirality in these novel compounds.Comment: 5 pages, 1 figure. Submitted to PR

Application of Sugar Foam to Vineyard Acid Soils under Mediterranean Conditions

Calcium (Ca) deficiency and aluminium (Al) toxicity are considered major chemical constraints that limitvine growth in vineyard acid soils under Mediterranean conditions. The main aim of this work was toevaluate the effects of three doses of sugar foam (900, 1 800 and 2 700 kg CaCO3/ha) on five soil properties(pH in water, Ca, Mg, K and Al exchangeable contents) and Ca concentrations in petioles and canes of onewine grape variety. Research was conducted over three seasons (2006 to 2008) in a random block design atLeón (Spain). The results for plants and soils were subjected to general lineal model analysis. As a result, onelinear model, validated through a cross-validation procedure, has been proposed to predict exchangeablecalcium levels in vineyard acid soils at véraison. Based on the results for the soils, the higher doses of sugarfoam (1 800 and 2 700 kg CaCO3/ha) were the most effective doses in decreasing Al exchangeable andincreasing Ca exchangeable contents. In addition, liming increased Ca content in petioles and decreasedCa content in canes, but in both cases these differences were not significant

Adaptive optimization for OpenCL programs on embedded heterogeneous systems

Heterogeneous multi-core architectures consisting of CPUs and GPUs are commonplace in today’s embedded systems. These architectures offer potential for energy efficient computing if the application task is mapped to the right core. Realizing such potential is challenging due to the complex and evolving nature of hardware and applications. This paper presents an automatic approach to map OpenCL kernels onto heterogeneous multi-cores for a given optimization criterion – whether it is faster runtime, lower energy consumption or a trade-off between them. This is achieved by developing a machine learning based approach to predict which processor to use to run the OpenCL kernel and the host program, and at what frequency the processor should operate. Instead of hand-tuning a model for each optimization metric, we use machine learning to develop a unified framework that first automatically learns the optimization heuristic for each metric off-line, then uses the learned knowledge to schedule OpenCL kernels at runtime based on code and runtime information of the program. We apply our approach to a set of representative OpenCL benchmarks and evaluate it on an ARM big.LITTLE mobile platform. Our approach achieves over 93% of the performance delivered by a perfect predictor.We obtain, on average, 1.2x, 1.6x, and 1.8x improvement respectively for runtime, energy consumption and the energy delay product when compared to a comparative heterogeneous-aware OpenCL task mapping scheme

Searching for G: A New evaluation of SPM-LS dimensionality

There has been increased interest in assessing the quality and usefulness of short versions of the Raven’s Progressive Matrices. A recent proposal, composed of the last twelve matrices of the Standard Progressive Matrices (SPM-LS), has been depicted as a valid measure of g. Nonetheless, the results provided in the initial validation questioned the assumption of essential unidimensionality for SPM-LS scores. We tested this hypothesis through two di erent statistical techniques. Firstly, we applied exploratory graph analysis to assess SPM-LS dimensionality. Secondly, exploratory bi-factor modelling was employed to understand the extent that potential specific factors represent significant sources of variance after a general factor has been considered. Results evidenced that if modelled appropriately, SPM-LS scores are essentially unidimensional, and that constitute a reliable measure of g. However, an additional specific factor was systematically identified for the last six items of the test. The implications of such findings for future work on the SPM-LS are discusse

Acción farmacológica del 2-para-amino-benzol en bovinos y equinos.

El objetivo de esta investigación realizada por la Facultad de Medicina Veterinaria y Zootecnia de la Universidad del Tolima, Laboratorios Synthesis, Eduardo García León y Maximiliano Delgado es contribuír en el área de la reproducción como un aporte de la técnica en el mejoramiento de la calidad del material espermático en reproductores equinos y bovinos dedicados a la producción de semen, tanto para inseminación rtificial como para monta directa. El ensayo propuesto se realizó en un tiempo de 75 días y con la posología de 50 mg/K de peso vivo para equinos. Una vez terminado el proceso experimental se encontró un mejoramiento de la actividad de la libido y de la calidad del material espermático, respecto a la obtenida en análisis previos a la investigación. Los efectos de este tratamiento se manifestaron de manera nítida tanto desde el punto de vista del envecimiento como del efecto sobre las gónadasEquinos-Caballo - caballo

Prescripciones de diuréticos de asa potencialmente inapropiadas en ancianos

ResumenObjetivoIdentificar la prescripción potencialmente inadecuada de diuréticos de asa como monoterapia de primera línea en hipertensión arterial de pacientes mayores de 65 años en Colombia.MétodosEstudio cuasiexperimental, prospectivo, antes y después, sin grupo control, mediante una intervención educativa dirigida a prescriptores de pacientes mayores de 65 años con diagnóstico de hipertensión arterial en manejo con furosemida en monoterapia, afiliados al régimen pago del Sistema de Salud de Colombia entre el 1°. de enero y el 30 de agosto de 2014. Luego de la identificación de los pacientes de una base de datos poblacional de dispensación de medicamentos y de la intervención se midió el cambio en la formulación.ResultadosDe un total de 453.017 sujetos en tratamiento antihipertensivo se identificaron 160 pacientes con diagnóstico de hipertensión arterial tratados con furosemida en monoterapia, con una edad media de 82,7±9,1 años. Se realizaron 76 actividades educativas sobre los médicos y se consiguió modificar la terapia en 67 pacientes (41,8% de los intervenidos), donde el 6,8% suspendió el diurético, pero inició un nuevo antihipertensivo, 13,1% agregó un antihipertensivo y 21,8% lo suspendió definitivamente. Ser anciano entre 65 y 74 años se asoció con mayor probabilidad de éxito en la intervención (OR: 2,2; IC95%:1,010-4,860; p<0,001).ConclusionesUna pequeña proporción de pacientes mayores de 65 años son tratados con furosemida en monoterapia antihipertensiva, pero las estrategias educativas y de seguimiento de las prescripciones pueden reducir su uso inapropiado. Es importante desarrollar herramientas que incentiven al médico a evitar prescripciones menos eficaces y seguras.AbstractMotivationTo identify the potentially inappropriate prescription of loop diuretics as a first-line monotherapy in arterial hypertension of patients over 65 years old in Colombia.MethodsQuasiexperimental, prospective, before and after study, without a control group, by means of an educational intervention aimed at prescriptors of patients over 65 years old with the diagnosis of arterial hypertension managed with furosemide in monotherapy, affiliated to the Colombian Health System between January 1st and August 30th 2014. After identifying the patients in a population database of medication dispensation and after the intervention, changes in the formulation were measured.ResultsOut of a total of 453,017 individuals taking antihypertensives, 160 patients were identified with arterial hypertension being treated with furosemide in monotherapy, with an average age of 82.7±9.1 years. 76 educational activities were carried out with physicians and therapy could be modified in 67 patients (47.8% of intervention participants), where 6.8% discontinued the diuretic, but initiated a new antihypertensive, 13.1% added an antihypertensive and 21.8% definitely suspended the treatment. Being between 65 and 74 years old was associated to a higher probability of success of the intervention (OR: 2.2; CI 95%: 1.010-4.860; p<0.001).ConclusionsA small proportion of patients over 65 years of age were treated with furosemide as antihypertensive monotherapy, but educational strategies and monitorisation of prescriptions may reduce their inappropriate use. It is important to develop tools to motivate the physician to avoid less efficient and safe prescriptions

Characterizing of steel used in the construction of civil works in Almería

Se realizaron varios ensayos sobre las barras de acero utilizadas en la construcción de obra civil en Almería, durante el período comprendido entre 18/1/2000 y 7/05/2001, con el fin de caracterizar, mecánicamente, los diferentes tipos de aceros (soldables: B400S, B500S y soldable dúctil: B400SD) y, de esta fonua, determinar si existe alguna razón técnica para un incremento del consumo del acero soldable dúctil. Para ello, se ensayaron a tracción todas las muestras que llegaron al laboratorio, siguiendo las normas UNE 7474-1: 1992 y UNE 7474-2:1992. Los resultados indican que el acero B400SD cumple, sólo, en un 86 % los límites especificados en la norma UNE 36065:1999 -EX, frente al 95 y 94 % de los aceros B400S y B500S. Además, el acero soldable dúctil muestra unos valores medios inferiores al B400S. Este hecho discrepa de lo que se podría esperar según la norma que lo regulaVarious tests have be en conducted on the steel bars used in the construction of civil works in Almería (Spain) during the period 18 ]anuary 2000-7 May 2001, with the aim of mechanically characterizing the different types of steel (weldable: B400S, B500S and ductile weldable: B400SD) to determine whether there is a technical reason for the increase in the use of ductile weldable steel. For this, we have used a hydraulic machine to break by traction all the test samples that arrived to the laboratory, following the specifications of the UNE 7474-1:1992 and the UNE 7474-2:1992. The results indicate that only in 86 % of the cases does the steel B400SD satisfy the limits specified by the UNE 36065:1999-EX, as opposed to 95 and 94 % of the B400S and B500S steels. In addition, the ductile weldable steel registered mean values lower than those of B400S. This finding disagrees with expectations set by the specifications

Identifying potential Plasmodium vivax sporozoite stage vaccine candidates : An analysis of genetic diversity and natural selection

Parasite antigen genetic diversity represents a great obstacle when designing a vaccine against malaria caused by Plasmodium vivax. Selecting vaccine candidate antigens has been focused on those fulfilling a role in invasion and which are conserved, thus avoiding specific-allele immune responses. Most antigens described to date belong to the blood stage, thereby blocking parasite development within red blood cells, whilst studying antigens from other stages has been quite restricted. Antigens from different parasite stages are required for developing a completely effective vaccine; thus, pre-erythrocyte stage antigens able to block the first line of infection becoming established should also be taken into account. However, few antigens from this stage have been studied to date. Several P. falciparum sporozoite antigens are involved in invasion. Since 77% of genes are orthologous amongst Plasmodium parasites, P. vivax sporozoite antigen orthologs to those of P. falciparum might be present in its genome. Although these genes might have high genetic diversity, conserved functionally-relevant regions (ideal for vaccine development) could be predicted by comparing genetic diversity patterns and evolutionary rates. This study was thus aimed at searching for putative P. vivax sporozoite genes so as to analyse their genetic diversity for determining their potential as vaccine candidates. Several DNA sequence polymorphism estimators were computed at each locus. The evolutionary force (drift, selection and recombination) drawing the genetic diversity pattern observed was also determined by using tests based on polymorphism frequency spectrum as well as the type of intra- and inter-species substitutions. Likewise, recombination was assessed both indirectly and directly. The results showed that sporozoite genes were more conserved than merozoite genes evaluated to date. Putative domains implied in cell traversal, gliding motility and hepatocyte interaction had a negative selection signal, being conserved amongst different species in the genus. PvP52, PvP36, PvSPATR, PvPLP1, PvMCP1, PvTLP, PvCelTOS, and PvMB2 antigens or functionally restricted regions within them would thus seem promising vaccine candidates and could be used when designing a pre-erythrocyte and/or multi-stage vaccine against P. vivax to avoid allele-specific immune responses that could reduce vaccine efficacy. © 2018 Garzón-Ospina, Buitrago, Ramos and Patarroyo