Tomographic Simulations of Accretion Disks in Cataclysmic Variables - Flickering and Wind

Both continuum and emission line flickering are phenomena directly associated with the mass accretion process. In this work we simulate accretion disk Doppler maps including the effects of winds and flickering flares. Synthetic flickering Doppler maps are calculated and the effect of the flickering parameters on the maps is explored. Jets and winds occur in many astrophysical objects where accretion disks are present. Jets are generally absent among the cataclysmic variables (CVs), but there is evidence of mass loss by wind in many objects. CVs are ideal objects to study accretion disks and consequently to study the wind associated with these disks. We also present simulations of accretion disks including the presence of a wind with orbital phase resolution. Synthetic H-alpha line profiles in the optical region are obtained and their corresponding Doppler maps are calculated. The effect of the wind simulation parameters on the wind line profiles is also explored. From this study we verified that optically thick lines and/or emission by diffuse material into the primary Roche lobe are necessary to generate single peaked line profiles, often seen in CVs. The future accounting of these effects is suggested for interpreting Doppler tomography reconstructions.Comment: 9 pages, 9 figure

Emission Line Flickering from the Secondary Star in Cataclysmic Variables? A study of V3885 Sagitarii

Spectrophotometric observations of H-alpha and He I 6678 emission lines of the nova-like Cataclysmic Variable V3885 Sgr are presented and analyzed. The binary orbital period was determined as P = 0.20716071(22) days. Doppler Tomography was performed with both H-alpha and He I lines. Disc radial emissivity profiles were also computed. The tomography mapping of flickering sources was performed using the H-alpha line, from which we concluded that the flickering is not uniformly distributed on the disc. The observed tomogram of the flickering was compared with simulations, suggesting that the most intense flickering source in the H-alpha is not located in the accretion disc. It is proposed that the main line flickering source may be associated with the illuminated secondary star.Comment: 19 pages, 10 figures, 1 table. Accepted to be published on AJ. to donwload high resolution figures: http://www.astro.iag.usp.br/~fabiola/V3885_hires.pd

A tomographic study of the classical nova RR Pic

We present the results of spectrophotometric observations of the old nova RR Pic performed in two spectral ranges, one centered in the Ha line and other covering Hb and Hg spectral lines. From the Hb radial velocity study we found a primary radial semi-amplitude of K1 = 37(1) km/s and a systemic velocity of g = 1.8(2) km/s. With this new values a mass diagram is constructed, constraining the possible mass intervals for the system. The possible orbital inclination range was restricted using the fact that RR Pic presents shallow eclipses. A secondary mass range below the limit of a main sequence star filling its Roche lobe indicate an evolved companion. We also calculated the Ha, Hb, Hg, HeI 6678 and HeII 4686 Doppler tomograms. The most conspicuous differences are found between the HeI and HeII tomograms, the former has a ring shape, while the second is filled at low velocities, suggesting that the low velocity emission is not coming from the accretion disk. Radial emissivity profiles for these lines were also derived.Comment: 8 pages, 8 figures, accepted to appear in PAS

Chemical analysis and evaluation of antioxidant and antimicrobial activities of fruit fractions of Mauritia flexuosa L. f. (Arecaceae)

Background Fruit consumption is currently considered beyond the nutritional aspects because of the important roles in disease prevention and benefits to health. The objective of this study was to characterize the chemical profile and evaluate the antioxidant and antimicrobial properties of different fractions obtained from fruit pulps of Mauritia flexuosa (MFFs). Methods Initially, chloroform, ethyl acetate and ethanol fractions were obtained from the pulps. Quantifications of total phenols and flavonoids were performed using the methods of Folin-Ciocalteu and complexation with aluminum chloride, respectively. Standard samples were used to identify and quantify phenolic acids and flavonoids using high-performance liquid chromatography with a diode-array detector (HPLC-DAD). The antioxidant capacity of the fractions was verified by sequestration of the free radical 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and iron chelating activity. The antimicrobial activity was determined using the microdilution method and the modulating activity was determined using sub-inhibitory concentrations of the fractions in association with antibiotics. Results The chemical analyzes revealed the presence of catechin, caffeic acid, rutin, orientin, quercetin, apigenin, luteolin and kaempferol, where all are present in the ethyl acetate fraction. The fractions exhibited moderate antioxidant and antimicrobial activities against Gram-positive and Candida strains in addition to modulating the activity of conventional antibiotics. The most expressive result was obtained from the association of the chloroform fraction with cefotaxime, which produced a synergistic effect, reducing the minimum inhibitory concentration (MIC) of the antibiotic from 1,024 to 256 μg/mL. Discussion The fractions presented a constitution rich in phenolic compounds, especially flavonoids. The data obtained demonstrated that the fractions presented moderate antioxidant activity by acting both as primary and secondary antioxidants. The fractions presented antimicrobial and antibiotic potentiating activities, being the first record of modulating effect of fractions of this species against the studied microbial strains, but failed in modulating the activity of antifungal drugs, indicating that this plant has the potential to be used in the development of therapeutic alternatives against resistant bacteria. The constitution phenolic the fractions may be responsible for their pharmacological properties in vitro

Antinociceptive and Anti-Inflammatory Effects of Octacosanol from the Leaves of Sabicea grisea var. grisea in Mice

Sabicea species are used in the Amazon for treatment of fever and malaria, which suggests that its chemical constituents may have some effect on pain and inflammation. Phytochemical analysis of the hexane fraction obtained from the crude ethanol extract from Sabicea grisea var. grisea Cham. & Schltdl (Rubiaceae), an endemic plant in Brazil, resulted in the isolation of octacosanol. This study investigated the antinociceptive and anti-inflammatory effects of the octacosanol in different experimental models. The crude ethanolic extract and hexane fraction obtained from the leaves of S. grisea produced an inhibition of acetic acid-induced pain. Moreover, octacosanol isolated from the hexane fraction produced a significant inhibition of pain response elicited by acetic acid. Pre-treatment with yohimbine, an alpha 2-adrenergic receptor antagonist, notably reversed the antinociceptive activity induced by octacosanol in the abdominal constriction test. Furthermore, mice treated with octacosanol did not exhibit any behavioral alteration during the hot plate and rota-rod tests, indicating non-participation of the supraspinal components in the modulation of pain by octacosanol with no motor abnormality. In the formalin test, octacosanol did not inhibit the licking time in first phase (neurogenic pain), but significantly inhibited the licking time in second phase (inflammatory pain) of mice. The anti-inflammatory effect of octacosanol was evaluated using carrageenan-induced pleurisy. The octacosanol significantly reduced the total leukocyte count and neutrophils influx, as well as TNF-α levels in the carrageenan-induced pleurisy. This study revealed that the mechanism responsible for the antinociceptive and anti-inflammatory effects of the octacosanol appears to be partly associated with an inhibition of alpha 2-adrenergic transmission and an inhibition of pathways dependent on pro-inflammatory cytokines. Finally, these results demonstrated that the octacosanol from the leaves of S. grisea possesses antinociceptive and anti-inflammatory activities, which could be of relevance for the pharmacological control of pain and inflammatory processes