15,906 research outputs found

    Modeling the input history of programs for improved instruction-memory performance

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    When a program is loaded into memory for execution, the relative position of its basic blocks is crucial, since loading basic blocks that are unlikely to be executed first places them high in the instruction-memory hierarchy only to be dislodged as the execution goes on. In this paper we study the use of Bayesian networks as models of the input history of a program. The main point is the creation of a probabilistic model that persists as the program is run on different inputs and at each new input refines its own parameters in order to reflect the program's input history more accurately. As the model is thus tuned, it causes basic blocks to be reordered so that, upon arrival of the next input for execution, loading the basic blocks into memory automatically takes into account the input history of the program. We report on extensive experiments, whose results demonstrate the efficacy of the overall approach in progressively lowering the execution times of a program on identical inputs placed randomly in a sequence of varied inputs. We provide results on selected SPEC CINT2000 programs and also evaluate our approach as compared to the gcc level-3 optimization and to Pettis-Hansen reordering

    Ensaios preliminares e cooperativos de fungicidas - resultados obtidos no Centro Nacional de Pesquisa de Trigo no perĂ­odo 1988-1991.

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    bitstream/item/119426/1/FOL-05091.pdfTítulo da capa: Controle químico de doenças do trigo: resultados de 1988 a 1991

    High coercivity induced by mechanical milling in cobalt ferrite powders

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    In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500oC. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The XPD analysis by the Williamson-Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples

    The Nature of the Optical Light in Seyfert 2 Galaxies with Polarized Continuum

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    We investigate the nature of the optical continuum and stellar population in the central kpc of the Seyfert 2s Mrk 348, Mrk 573, NGC 1358 and Mrk 1210 using long-slit spectra obtained along the radio or extended emission axis. These galaxies are known to have polarized continuum-including polarized broad lines in Mrk 348 and Mrk 1210--and previous studies indicate featureless continuum (FC) contributions in the 20-50% range at 5500 A. Nevertheless, our measurements of the equivalent widths of absorption lines and continuum ratios as a function of distance from the nuclei show no dilution of the lines nor bluening of the spectrum, as expected if a blue FC was present at the nucleus in the above proportions. We investigate one possibility to account for this effect: that the stellar population at the nucleus is the same as that from the surrounding bulge and dominates the nuclear light. A spectral analysis confirms that this hypothesis works for Mrk 348, NGC 1358 and Mrk 1210, for which we find stellar contributions at the nucleus larger than 90% at all wavelengths. We find that a larger stellar population contribution to the nuclear spectra can play the role of the ``second FC'' source inferred from previous studies. Stellar population synthesis shows that the nuclear regions of Mrk 348 and Mrk 1210 have important contributions of young to intermediate age stars (0--100 Myr), not present in templates of elliptical galaxies. In the case of Mrk 1210, this is further confirmed by the detection of a ``Wolf-Rayet feature'' in the nuclear emission-line spectrum.Comment: ApJ, accepted. Uses aaspp4.sty. [22 pages

    Costs Associated with Malaria in Pregnancy in the Brazilian Amazon, a Low Endemic Area Where Plasmodium vivax Predominates.

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    BACKGROUND: Information on costs associated with malaria in pregnancy (MiP) in low transmission areas where Plasmodium vivax predominates is so far missing. This study estimates health system and patient costs of MiP in the Brazilian Amazon. METHODS/PRINCIPAL FINDINGS: Between January 2011 and March 2012 patient costs for the treatment of MiP were collected through an exit survey at a tertiary referral hospital and at a primary health care centre in the Manaus metropolitan area, Amazonas state. Pregnant and post-partum women diagnosed with malaria were interviewed after an outpatient consultation or at discharge after admission. Seventy-three interviews were included in the analysis. Ninety-six percent of episodes were due to P. vivax and 4% to Plasmodium falciparum. In 2010, the total median costs from the patient perspective were estimated at US 45.91andUS45.91 and US 216.29 for an outpatient consultation and an admission, respectively. When multiple P. vivax infections during the same pregnancy were considered, patient costs increased up to US 335.85,representingthecostsofanadmissionplusanoutpatientconsultation.Providerdirectandoverheadcostdatawereobtainedfromseveralsources.Theprovidercostassociatedwithanoutpatientcase,whichincludesseveralconsultationsatthetertiaryhospitalwasUS335.85, representing the costs of an admission plus an outpatient consultation. Provider direct and overhead cost data were obtained from several sources. The provider cost associated with an outpatient case, which includes several consultations at the tertiary hospital was US 103.51 for a P. vivax malaria episode and US 83.59foraP.falciparummalariaepisode.Thecostofaninpatientdayandaverageadmissionof3dayswasUS83.59 for a P. falciparum malaria episode. The cost of an inpatient day and average admission of 3 days was US 118.51 and US 355.53,respectively.TotalprovidercostsforthediagnosisandtreatmentofallmalariacasesreportedinpregnantwomeninManausin2010(N=364)wereUS355.53, respectively. Total provider costs for the diagnosis and treatment of all malaria cases reported in pregnant women in Manaus in 2010 (N = 364) were US 17,038.50, of which 92.4% (US$ 15,741.14) due to P. vivax infection. CONCLUSION: Despite being an area of low risk malaria transmission, MiP is responsible for a significant economic burden in Manaus. Especially when multiple infections are considered, costs associated with P. vivax are higher than costs associated with P. falciparum. The information generated may help health policy decisions for the current control and future elimination of malaria in the area
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