9,680 research outputs found

    Complex bounds for multimodal maps: bounded combinatorics

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    We proved the so called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus. The complex bounds is the first step to extend the renormalization theory of unimodal maps to multimodal maps.Comment: 20 pages, 3 figure

    Insetos Praga e Benéficos na Cultura do Tungue.

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    bitstream/CPACT-2010/12917/1/documento-276.pd

    Search for associations containing young stars (SACY) VII. New stellar and substellar candidate members in the young associations

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    The young associations offer us one of the best opportunities to study the properties of young stellar and substellar objects and to directly image planets thanks to their proximity (<<200 pc) and age (\approx5-150 Myr). However, many previous works have been limited to identifying the brighter, more active members (\approx1 M_\odot) owing to photometric survey sensitivities limiting the detections of lower mass objects. We search the field of view of 542 previously identified members of the young associations to identify wide or extremely wide (1000-100,000 au in physical separation) companions. We combined 2MASS near-infrared photometry (JJ, HH, KK) with proper motion values (from UCAC4, PPMXL, NOMAD) to identify companions in the field of view of known members. We collated further photometry and spectroscopy from the literature and conducted our own high-resolution spectroscopic observations for a subsample of candidate members. This complementary information allowed us to assess the efficiency of our method. We identified 84 targets (45: 0.2-1.3 M_\odot, 17: 0.08-0.2 M_\odot, 22: <<0.08 M_\odot) in our analysis, ten of which have been identified from spectroscopic analysis in previous young association works. For 33 of these 84, we were able to further assess their membership using a variety of properties (X-ray emission, UV excess, Hα_\alpha, lithium and K I equivalent widths, radial velocities, and CaH indices). We derive a success rate of 76-88% for this technique based on the consistency of these properties. Once confirmed, the targets identified in this work would significantly improve our knowledge of the lower mass end of the young associations. Additionally, these targets would make an ideal new sample for the identification and study of planets around nearby young stars.Comment: 28 pages, 24 figures, accepted in A&

    Search for associations containing young stars (SACY). VI. Is multiplicity universal? Stellar multiplicity in the range 3-1000 au from adaptive-optics observations

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    Context. Young loose nearby associations are unique samples of close (<150 pc), young (approx 5-100 Myr) pre-main sequence (PMS) stars. A significant number of members of these associations have been identified in the SACY collaboration. We can use the proximity and youth of these members to investigate key ingredients in star formation processes, such as multiplicity. Aims. We present the statistics of identified multiple systems from 113 confirmed SACY members. We derive multiplicity frequencies, mass-ratio, and physical separation distributions in a consistent parameter space, and compare our results to other PMS populations and the field. Methods. We have obtained adaptive-optics assisted near-infrared observations with NACO (ESO/VLT) and IRCAL (Lick Observatory) for at least one epoch of all 113 SACY members. We have identified multiple systems using co-moving proper-motion analysis and using contamination estimates. We have explored ranges in projected separation and mass-ratio of a [3-1000 au], and q [0.1-1], respectively. Results. We have identified 31 multiple systems (28 binaries and 3 triples). We derive a multiplicity frequency (MF) of MF_(3-1000au)=28.4 +4.7, -3.9% and a triple frequency (TF) of TF_(3-1000au)=2.8 +2.5, -0.8% in the separation range of 3-1000 au. We do not find any evidence for an increase in the MF with primary mass. The estimated mass-ratio of our statistical sample (with power-law index gamma=-0.04 +/- 0.14) is consistent with a flat distribution (gamma = 0). Conclusions. We show further similarities (but also hints of discrepancies) between SACY and the Taurus region: flat mass-ratio distributions and statistically similar MF and TF values. We also compared the SACY sample to the field (in the separation range of 19-100 au), finding that the two distributions are indistinguishable, suggesting a similar formation mechanism.Comment: 16 Pages, accepted in A&A 28 May 201

    Ovinos prolíficos FecGe: 50% de cordeiros a mais.

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    bitstream/item/143223/1/Folder-FecGE.pd

    Manipueira: its use in obtaining a biofungicide.

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    In the search for an alternative to the intensive use of fungicides in crop production, a soil bacterium was isolated in Guaira, Sao Paulo State (Brazil). This Bacillus gave good control of the fungus Fusarium solani, an important plant disease. In order to apply this bacterium in larger experimental areas, it was necessary to study its production by liquid fermentation on cheap agroindustrial residues. Manipueira (the waste water from cassava flour industry) was the main component of the medium, supplemented by sugarcane molasses. It was inoculated with the Bacillus sp. (isolated from Guaira soil) and incubated under constant agitation and temperatura in 250 ml Erlenmeyer flasks. Bacterial growth, pH and sugar consumption were analyzed over 48 h of fermentation. The results obtained indicated the ability of the residue to support the growth of the strain tested and the importance of scaling up the fermentation process
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