13 resultados para around Svalbard

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Sunken parcels of macroalgae and wood provide important oases of organic enrichment at the deep-sea floor, yet sediment community structure and succession around these habitat islands are poorly evaluated. We experimentally implanted 100-kg kelp falls and 200 kg wood falls at 1670 m depth in the Santa Cruz Basin to investigate (1) macrofaunal succession and (2) species overlap with nearby whale-fall and cold-seep communities over time scales of 0.25-5.5 yr. The abundance of infaunal macrobenthos was highly elevated after 0.25 and 0.5 yr near kelp parcels with decreased macrofaunal diversity and evenness within 0.5 m of the falls. Apparently opportunistic species (e.g., two new species of cumaceans) and sulfide tolerant microbial grazers (dorvilleid polychaetes) abounded after 0.25-0.5 yr. At wood falls, opportunistic cumaceans become abundant after 0.5 yr, but sulfide tolerant species only became abundant after 1.8-5.5 yr, in accordance with the much slower buildup of porewater sulfides at wood parcels compared with kelp falls. Species diversity decreased significantly over time in sediments adjacent to the wood parcels, most likely due to stress resulting from intense organic loading of nearby sediments (up to 20-30% organic carbon). Dorvilleid and ampharetid polychaetes were among the top-ranked fauna at wood parcels after 3.0-5.5 yr. Sediments around kelp and wood parcels provided low-intensity reducing conditions that sustain a limited chemoautrotrophically-based fauna. As a result, macrobenthic species overlap among kelp, wood, and other chemosynthetic habitats in the deep NE Pacific are primarily restricted to apparently sulfide tolerant species such as dorvilleid polychaetes, opportunistic cumaceans, and juvenile stages of chemosymbiont containing vesicomyid bivalves. We conclude that organically enriched sediments around wood falls may provide important habitat islands for the persistence and evolution of species dependent on organic- and sulfide-rich conditions at the deep-sea floor and contribute to beta and gamma diversity in deep-sea ecosystems. (C) 2010 Elsevier Ltd. All rights reserved.

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Sediments from Admiralty Bay, Antarctica were collected during the austral summers of 2002/2003 and 2003/2004 in order to assess the distribution and concentration of sewage indicators originating from Comandante Ferraz Brazilian Antarctic Station. Fecal sterols (coprostanol + epicoprostanol) and linear alkylbenzenes (LABs) ranged from <0.01 to 0.95 mu g g(-1) and <1.0 to 23 ng g(-1) dry weight, respectively. In general, the higher concentrations were found only locally in the vicinity of Ferraz station at Martel Inlet. Baseline values for fecal sterols and coprostanone were calculated as 0.19 and 0.40 mu g g(-1), respectively. According to fecal sterols concentrations, sewage contribution to Martel Inlet has increased more than twice since 1997, as result of the increase in the number of researchers at the station especially during the last decade. A low correlation was found between total LABs and fecal steroids, which could be attributed to the contribution of the natural sources of steroids. (C) 2010 Elsevier B.V. All rights reserved.

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Background Mental and physical disorders are associated with total disability, but their effects on days with partial disability (i.e. the ability to perform some, but not full-role, functioning in daily life) are not well understood. Aims To estimate individual (i.e. the consequences for an individual with a disorder) and societal effects (i.e. the avoidable partial disability in the society due to disorders) of mental and physical disorders on days with partial disability around the world. Method Respondents from 26 nationally representative samples (n=61 259, age 18+) were interviewed regarding mental and physical disorders, and day-to-day functioning. The Composite International Diagnostic Interview, version 3.0 (CIDI 3.0) was used to assess mental disorders; partial disability (expressed in full day equivalents) was assessed with the World Health Organization Disability Assessment Schedule in the CIDI 3.0. Results Respondents with disorders reported about 1.58 additional disability days per month compared with respondents without disorders. At the individual level, mental disorders (especially post-traumatic stress disorder, depression and bipolar disorder) yielded a higher number of days with disability than physical disorders. At the societal level, the population attributable risk proportion due to physical and mental disorders was 49% and 15% respectively. Conclusions Mental and physical disorders have a considerable impact on partial disability, at both the individual and at the societal level. Physical disorders yielded higher effects on partial disability than mental disorders.

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Background. The aim of this paper was to clarify if previously established prognostic factors explain the different mortality, rates observed in ICU septic patients around the world. Methods. This is a sub-study from the PROGRESS study, which was an international, prospective, observational registry of ICU patients with severe sepsis. For this study we included 10930 patients from 24 countries that enrolled more than 100 patients in the PROGRESS. The effect of potential prognostic factors on in-hospital mortality was examined using univariate and multivariate logistic regression. The complete set of data was available for 7022 patients, who were considered in the multivariate analysis. Countries were classified according to country, income, development status, and in-hospital mortality terciles. The relationship between countries' characteristics and hospital mortality mortality was evaluated using linear regression. Results. Mean in-hospital mortality was 49.2%. Severe sepsis in-hospital mortality varied widely in different countries, ranging from 30.6% in New Zealand to 80.4% in Algeria. Classification as developed or developing country was not associated with in-hospital mortality (P=0.16), nor were levels of gross national product per capita (P=0.15). Patients in the group of countries with higher in-hospital mortality, had a crude OR for in-hospital death of 2.8 (95% CI 2.5-3.1) in comparison to those in the lower risk group. After adjustments were made for all other independent variables, the OR changed to 2.9 (95% CI 2.5-3.3). Conclusion. Severe sepsis mortality varies widely, in different countries. All known markers of disease severity and prognosis do not fully, explain the international differences in mortality,. Country, income does not explain this disparity, either. Further studies should be developed to verify if other organizational or structural factors account for disparities in patient care and outcomes. (Minerva Anestesiol 2012;78:1215-25)

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Local structure around Fe ions on Pb(Fe1/2Nb1/2)O-3 ceramics was probed by x-ray absorption spectroscopy in order to settle the controversies about its structure. It is observed that the shell structure around Fe atoms exhibits a monoclinic local symmetry at 130 and 230 K, tetragonal local symmetry at room temperature, and cubic local symmetry at 410 K. Independently of the coordination, temperature, or symmetry, Fe-O mean bond-length does not vary significantly. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4709490]

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Objective: To describe the healing of marginal defects below or above 1 mm of dimension around submerged implants in a dog model. Material and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Two recipient sites were prepared and the marginal 5mm were widened to such an extent to obtain, after implant installation, a marginal gap of 0.5mm at the mesial site (small defect) and of 1.25mm at the distal site (large defect). Titanium healing caps were affixed to the implants and the flaps were sutured allowing a fully submerged healing. The experimental procedures were subsequently performed in the left side of the mandible. The timing of the experiments and sacrifices were planned in such a way to obtain biopsies representing the healing after 5, 10, 20 and 30 days. Ground sections were prepared and histomorphometrically analyzed. Results: The filling of the defect with newly formed bone was incomplete after 1 month of healing in all specimens. Bone formation occurred from the base and the lateral walls of the defects. A larger volume of new bone was formed in the large compared with the small defects. Most of the new bone at the large defect was formed between the 10- and the 20-day period of healing. After 1 month of healing, the outline of the newly formed bone was, however, located at a similar distance from the implant surface (about 0.4mm) at both defect types. Only minor newly formed bone in contact with the implant, starting from the base of the defects, was seen at the large defects (about 0.8mm) while a larger amount was detected at the small defects (about 2.2 mm). Conclusion: Marginal defects around titanium implants appeared to regenerate in 20-30 days by means of a distance osteogenesis. The bone fill of the defects was, however, incomplete after 1 month.

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Background: Accelerating bone healing around dental implants can reduce the long-term period between the insertion of implants and functional rehabilitation. Objective: This in vivo study evaluated the effect of a constant electromagnetic field (CEF) on bone healing around dental implants in dogs. Materials and methods: Eight dental implants were placed immediately after extraction of the first premolar and molar teeth on the mandible of two male dogs and divided into experimental (CEF) and control groups. A CEF at magnetic intensity of 0.8 mT with a pulse width of 25 mu s and frequency of 1.5 MHz was applied on the implants for 20 min per day for 2 weeks. Result and conclusion: After qualitative histological analysis, a small quantity of newly formed bone was observed in the gap between the implant surface and alveolar bone in both groups.

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We present a direct measurement of the low-energy Li-8(p, alpha)He-5 cross section, using a radioactive Li-8 beam impinging on a thick target. With four beam energies, we cover the energy range between E-c.m. = 0.2 and 2.1 MeV. An R-matrix analysis of the data is performed and suggests the existence of two broad overlapping resonances (5/2(+) at E-c.m. = 1.69 MeV and 7/2(+) at E-c.m. = 1.76 MeV). At low energies our data are sensitive to the properties of a subthreshold state (E-x = 16.67 MeV) and of two resonances above threshold. These resonances were observed in previous experiments. The R-matrix fit confirms spin assignments, and provides partial widths. We propose a new Li-8(p, alpha)He-5 reaction rate and briefly discuss its influence in nuclear astrophysics. DOI: 10.1103/PhysRevC.86.064321

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Aims. We report the discovery of CoRoT-16b, a low density hot jupiter that orbits a faint G5V star (mV = 15.63) in 5.3523 +/- 0.0002 days with slight eccentricity. A fit of the data with no a priori assumptions on the orbit leads to an eccentricity of 0.33 +/- 0.1. We discuss this value and also derive the mass and radius of the planet. Methods. We analyse the photometric transit curve of CoRoT-16 given by the CoRoT satellite, and radial velocity data from the HARPS and HIRES spectrometers. A combined analysis using a Markov chain Monte Carlo algorithm is used to get the system parameters. Results. CoRoT-16b is a 0.535 -0.083/+0.085 M-J, 1.17 -0.14/+0.16 R-J hot Jupiter with a density of 0.44 -0.14/+0.21 g cm(-3). Despite its short orbital distance (0.0618 +/- 0.0015 AU) and the age of the parent star (6.73 +/- 2.8 Gyr), the planet orbit exhibits significantly non-zero eccentricity. This is very uncommon for this type of objects as tidal effects tend to circularise the orbit. This value is discussed taking into account the characteristics of the star and the observation accuracy.

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Objective: To verify if mini-implant mobility is affected by the presence of periodontopathogens, frequently associated with peri-implantitis. Materials and Methods: The surfaces of 31 mini-implants used for skeletal anchorage in orthodontic patients were evaluated. Polymerase chain reaction was used for identification of the presence of DNA from three different periodontopathogens (P. intermedia [Pi], A. actinomycetemcomitans [Aa], and P. gingivalis [Pg]) in 16 mini-implants without mobility (control group) and 15 mini-implants with mobility (experimental group). Results: The results showed that Pi was present in 100% of the samples, from both groups: Aa was found in 31.3% of the control group and in 13.3% of the experimental group. Pg was detected in 37.4% of the control group and in 33.3% of the experimental group. The Fisher exact test and the odds ratio (OR) values for Aa and Pg (OR = 0.34; 95% confidence interval [CI]: 0.05-2.10 and OR = 0.61; 95% Cl: 0.13-2.79, respectively) showed no significant association (P > .05) between the periodontopathogens studied and the mobility of the mini-implants. Conclusions: It can be concluded that the presence of Aa, Pi, and Pg around mini-implants is not associated with mobility. (Angle Orthod. 2012;82:591-595.)

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Be stars possess gaseous circumstellar disks that modify in many ways the spectrum of the central B star. Furthermore, they exhibit variability at several timescales and for a large number of observables. Putting the pieces together of this dynamical behavior is not an easy task and requires a detailed understanding of the physical processes that control the temporal evolution of the observables. There is an increasing body of evidence that suggests that Be disks are well described by standard alpha-disk theory. This paper is the first of a series that aims at studying the possibility of inferring several disk and stellar parameters through the follow-up of various observables. Here we study the temporal evolution of the disk density for different dynamical scenarios, including the disk buildup as a result of a long and steady mass injection from the star, the disk dissipation that occurs after mass injection is turned off, as well as scenarios in which active periods are followed by periods of quiescence. For those scenarios, we investigate the temporal evolution of continuum photometric observables using a three-dimensional non-LTE radiative transfer code. We show that light curves for different wavelengths are specific of a mass loss history, inclination angle, and alpha viscosity parameter. The diagnostic potential of those light curves is also discussed.

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CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 ( LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observations, however, were performed mainly by the 10-m Keck telescope in January 2010. The companion CoRoT-21b is a Jupiter-like planet of 2.26 +/- 0.33 Jupiter masses and 1.30 +/- 0.14 Jupiter radii in an circular orbit of semi-major axis 0.0417 +/- 0.0011 AU and an orbital period of 2.72474 +/- 0.00014 days. The planetary bulk density is ( 1.36 +/- 0.48) x 10(3) kg m(-3), very similar to the bulk density of Jupiter, and follows an M-1/3 - R relation like Jupiter. The F8IV star is a sub-giant star of 1.29 +/- 0.09 solar masses and 1.95 +/- 0.2 solar radii. The star and the planet exchange extreme tidal forces that will lead to orbital decay and extreme spin-up of the stellar rotation within 800 Myr if the stellar dissipation is Q(*)/k2(*) <= 107.

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We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (≈1.5-2.5 M ☉) conducted to date and includes the planet hosts β Pic and Fomalhaut. We obtained follow-up astrometry of all candidate companions within 400 AU projected separation for stars in uncrowded fields and identified new low-mass companions to HD 1160 and HIP 79797. We have found that the previously known young brown dwarf companion to HIP 79797 is itself a tight (3 AU) binary, composed of brown dwarfs with masses 58$^{+21}_{-20}$ M Jup and 55$^{+20}_{-19}$ M Jup, making this system one of the rare substellar binaries in orbit around a star. Considering the contrast limits of our NICI data and the fact that we did not detect any planets, we use high-fidelity Monte Carlo simulations to show that fewer than 20% of 2 M ☉ stars can have giant planets greater than 4 M Jup between 59 and 460 AU at 95% confidence, and fewer than 10% of these stars can have a planet more massive than 10 M Jup between 38 and 650 AU. Overall, we find that large-separation giant planets are not common around B and A stars: fewer than 10% of B and A stars can have an analog to the HR 8799 b (7 M Jup, 68 AU) planet at 95% confidence. We also describe a new Bayesian technique for determining the ages of field B and A stars from photometry and theoretical isochrones. Our method produces more plausible ages for high-mass stars than previous age-dating techniques, which tend to underestimate stellar ages and their uncertainties.