937 resultados para Early-late estimator


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Des preuves archéopalynologiques directes appuient maintenant l’hypothèse d’une lente adaptation horticole durant la néolithisation amérindienne de la région de Montréal. Les sites archéologiques Hector-Trudel (BhFl-1a) de Pointe-du-Buisson et Séminaire de Saint-Sulpice (BjFj-18) dans le Vieux-Montréal ont été retenus pour élaborer une méthodologie archéopalynologique d’étude des sols archéologiques. Cela a permis de caractériser l’impact de la présence humaine sur l'environnement végétal des sites et d’identifier des indices de culture et de gestion de plantes allogènes et indigènes. Un complexe horticole de production à petite échelle de maïs (Zea mays), de tournesol (Helianthus annuus) et de petit tabac (Nicotiana rustica) et une forme de gestion des arbustes à petits fruits sont identifiés au site Hector-Trudel durant le Sylvicole moyen tardif (500 à 1000 A.D.). Ces cultigènes sont aussi identifiés au site du Séminaire pour la fin du Sylvicole supérieur ancien (1200 à 1300 A.D.), dans des proportions toutefois plus importantes, et une activité de gestion forestière au profit des arbres à noix et du tilleul d’Amérique (Tilia americana), reflet des pratiques d’entretien des champs cultivés, témoignent d’une évolution dans les comportements

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This study considers the strength of the Northern Hemisphere Holton-Tan effect (HTE) in terms of the phase alignment of the quasi-biennial oscillation (QBO) with respect to the annual cycle. Using the ERA-40 Reanalysis, it is found that the early winter (Nov–Dec) and late winter (Feb–Mar) relation between QBO phase and the strength of the stratospheric polar vortex is optimized for subsets of the 44-year record that are chosen on the basis of the seasonality of QBO phase transitions at the 30 hPa level. The timing of phase transitions serves as a proxy for changes in the vertical structure of the QBO over the whole depth of the tropical stratosphere. The statistical significance of the Nov–Dec (Feb–Mar) HTE is greatest when 30 hPa QBO phase transitions occur 9–14 (4–9) months prior to the January of the NH winter in question. This suggests that there exists for both early and late winter a vertical structure of tropical stratospheric winds that is most effective at influencing the interannual variability of the polar vortex, and that an early (late) winter HTE is associated with an early (late) progression of QBO phase towards that structure. It is also shown that the seasonality of QBO phase transitions at 30 hPa varies on a decadal timescale, with transitions during the first half of the calendar year being relatively more common during the first half of the tropical radiosonde wind record. Combining these two results suggests that decadal changes in HTE strength could result from the changing seasonality of QBO phase transitions. Citation: Anstey, J. A., and T. G. Shepherd (2008), Response of the northern stratospheric polar vortex to the seasonal alignment of QBO phase transitions, Geophys. Res. Lett., 35, L22810, doi:10.1029/2008GL035721.

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We report 6 K-Ar ages and paleomagnetic data from 28 sites collected in Jurassic, Lower Cretaceous and Paleocene rocks of the Santa Marta massif, to test previous hypothesis of rotations and translations of this massif, whose rock assemblage differs from other basement-cored ranges adjacent to the Guyana margin. Three magnetic components were identified in this study. A first component has a direction parallel to the present magnetic field and was uncovered in all units (D 352, I = 25.6, k = 57.35, a95 = 5.3, N = 12). A second component was isolated in Cretaceous limestone and Jurassic volcaniclastic rocks (D = 8.8, I = 8.3, k = 24.71, a95 = 13.7, N = 6), and it was interpreted as of Early Cretaceous age. In Jurassic sites with this component, Early Cretaceous K-Ar ages obtained from this and previous studies are interpreted as reset ages. The third component was uncovered in eight sites of Jurassic volcaniclastic rocks, and its direction indicates negative shallow to moderate inclinations and northeastward declinations. K-Ar ages in these sites are of Early (196.5 +/- 4.9 Ma) to early Late Jurassic age (156.6 +/- 8.9 Ma). Due to local structural complexity and too few Cretaceous outcrops to perform a reliable unconformity test, we only used two sites with (1) K-Ar ages, (2) less structural complexity, and (3) reliable structural data for Jurassic and Cretaceous rocks. The mean direction of the Jurassic component is (D = 20.4, I = -18.2, k = 46.9, a95 = 5.1, n = 18 specimens from two sites). These paleomagnetic data support previous models of northward along-margin translations of Grenvillian-cored massifs. Additionally, clockwise vertical-axis rotation of this massif, with respect to the stable craton, is also documented; the sense of rotation is similar to that proposed for the Perija Range and other ranges of the southern Caribbean margin. More data is needed to confirm the magnitudes of rotations and translations. (C) 2009 Elsevier Ltd. All rights reserved.

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Pós-graduação em Bases Gerais da Cirurgia - FMB

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Pós-graduação em Genética e Melhoramento Animal - FCAV

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Purpose: To estimate the metabolic activity of rectal cancers at 6 and 12 weeks after completion of chemoradiation therapy (CRT) by 2-[fluorine-18] fluoro-2-deoxy-D-glucose-labeled positron emission tomography/computed tomography ([18 FDG] PET/CT) imaging and correlate with response to CRT. Methods and Materials: Patients with cT2-4N0-2M0 distal rectal adenocarcinoma treated with long-course neoadjuvant CRT (54 Gy, 5-fluouracil-based) were prospectively studied (ClinicalTrials. org identifier NCT00254683). All patients underwent 3 PET/CT studies (at baseline and 6 and 12 weeks fromCRT completion). Clinical assessment was at 12 weeks. Maximal standard uptakevalue (SUVmax) of the primary tumor wasmeasured and recorded at eachPET/CTstudy after 1 h (early) and3 h (late) from 18 FDGinjection. Patientswith an increase in early SUVmax between 6 and 12 weeks were considered " bad" responders and the others as "good" responders. Results: Ninety-one patients were included; 46 patients (51%) were "bad" responders, whereas 45 (49%) patients were " good" responders. " Bad" responders were less likely to develop complete clinical response (6.5% vs. 37.8%, respectively; PZ. 001), less likely to develop significant histological tumor regression (complete or near-complete pathological response; 16% vs. 45%, respectively; PZ. 008) and exhibited greater final tumor dimension (4.3cmvs. 3.3cm; PZ. 03). Decrease between early (1 h) and late (3 h) SUVmax at 6-week PET/CTwas a significant predictor of " good" response (accuracy of 67%). Conclusions: Patients who developed an increase in SUVmax after 6 weeks were less likely to develop significant tumor downstaging. Early-late SUVmax variation at 6-week PET/CT may help identify these patients and allow tailored selection of CRT-surgery intervals for individual patients. (C) 2012 Elsevier Inc.

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Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute flavored solutions accompanied by IG high-fat infusion (+ sessions) or water (− sessions). Each session included an “Early” flavor for 8 min followed by a “Late” flavor for 8 min. Learned preferences were then assessed in two-bottle tests (no IG infusion) between Early(+) vs. Early(−), Late(+) vs. Late(−), Early(+) vs. Late(+), and Early(−) vs. Late(−). Rats only preferred Late(+), not Early(+), relative to their respective (−) flavors. In a second experiment rats trained with a higher fat concentration learned to prefer Early(+) but more strongly preferred Late(+). Learned preferences were evident when rats were tested deprived or recently satiated. Unlike with glucose, ingested fat appears to produce a slower-onset rewarding signal, detected later in a meal or after its termination, becoming more strongly associated with flavors towards the end of the meal. This potentially contributes to enhanced liking for dessert foods, which persists even when satiated.

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Rats learn to prefer flavors associated with postingestive effects of nutrients. The physiological signals underlying this postingestive reward are unknown. We have previously shown that rats readily learn to prefer a flavor that was consumed early in a multi-flavored meal when glucose is infused intragastrically (IG), suggesting rapid postingestive reward onset. The present experiments investigate the timing of postingestive fat reward, by providing distinctive flavors in the first and second halves of meals accompanied by IG fat infusion. Learning stronger preference for the earlier or later flavor would indicate when the rewarding postingestive effects are sensed. Rats consumed sweetened, calorically-dilute flavored solutions accompanied by IG high-fat infusion (+ sessions) or water (- sessions). Each session included an "Early" flavor for 8min followed by a "Late" flavor for 8min. Learned preferences were then assessed in two-bottle tests (no IG infusion) between Early(+) vs. Early(-), Late(+) vs. Late(-), Early(+) vs. Late(+), and Early(-) vs. Late(-). Rats only preferred Late(+), not Early(+), relative to their respective (-) flavors. In a second experiment rats trained with a higher fat concentration learned to prefer Early(+) but more strongly preferred Late(+). Learned preferences were evident when rats were tested deprived or recently satiated. Unlike with glucose, ingested fat appears to produce a slower-onset rewarding signal, detected later in a meal or after its termination, becoming more strongly associated with flavors towards the end of the meal. This potentially contributes to enhanced liking for dessert foods, which persists even when satiated.

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BACKGROUND To evaluate toxicity and outcome of intensity modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) to the positive lymph nodes in patients with loco-regional advanced cervical cancer (LRACC). METHODS The study population comprised ten patients with 18FDG-PET\CT positive lymph nodes (LNs), who underwent chemoradiation with IMRT and SIB. A dose of 50.4 Gy, in daily fractions of 1.8 Gy, was delivered to primary tumor and draining LNs. Primary tumor received an additional external beam boost to a total dose of 55.8 Gy. A SIB of 62 Gy, in daily fractions of 2 Gy, was delivered to the 18FDG-PET\CT positive LNs. Finally, a high dose rate brachytherapy (HDRB) boost (15 - 18 Gy) was administered to the primary tumor. The primary goal of this study was to evaluate acute and early late toxicity and loco-regional control. RESULTS The median number of irradiated LNs per patient was 3 (range: 1-6) with a median middle nodal SIB-volume of 26.10 cm3 (range, 11.9-82.50 cm3). Median follow-up was 20 months (range, 12 to 30 months). Acute and late grade 3 toxicity was observed in 1 patient. Three of the patients developed a recurrence, one in the form of a local tumor relapse, one had a paraaortic LN metastasis outside the treated volume and the last one developed a distant metastasis. CONCLUSION IMRT with SIB in the region of 18FDG-PET positive lymph nodes appears to be an effective therapy with acceptable toxicity and might be useful in the treatment of patients with locally advanced cervical cancer.

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This paper describes the present-day vegetation, stratigraphy and developmental history of the mire of Egelsee-Moor (Salzburg, Austria; 45°45′N, 13°8.5′E, 700 m a.s.l., 15 ha in area) since the early Late Glacial on the basis of 4 transects with 14 trial borings across the peatland. We present a vegetation map of the mire, a longitudinal section through the peat body based on six cores showing the peat types, overview macrofossil diagrams of six cores showing the local mire development and two pollen diagrams covering the Late Glacial and Holocene. The chronology of the diagrams depends on biostratigraphic dating for the Late Glacial and early Holocene and radiocarbon dating for the remaining Holocene. The northern part of the mire originated through terrestrialisation of nutrient-rich, mostly inundated fen and the southern part through paludification of wet soils. The very small lake of today was a reservoir until recently for providing water-power for timber rafting (‘Holztrift’). The mire vegetation today is a complex of forested parts (mainly planted Pinus sylvestris and Thuja occidentalis, but also spontaneous Picea abies, Betula pubescens and Frangula alnus), reed-lands (Phragmites) and litter meadows (Molinietum, Schoenetum, etc.). The central part has hummock-hollow complexes with regionally rare species of transitional mires (Drosera anglica, D. intermedia, Lycopodiella inundata, Scorpidium scorpioides, Sphagnum platyphyllum, S. subnitens). The results indicate that some of the mid-Holocene sediments may have been removed by the timber-rafting practices, and that water extraction from the hydrological catchment since 1967 has resulted in a partial shift of transitional mire to ombrotrophic bog. The latter potentially endangers the regionally rare species and was used as an argument to stop further water extraction.

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Benthic foraminiferal assemblages are a widespread tool to understand changes in organic matter flux and bottom-water oxygenation and their relation to paleoceanographic changes in the Upper Cretaceous oceans. In this study, assemblage data (diversity, total number, and number per species and gram) from Deep Sea Drilling Project (DSDP) Site 390 (Blake Nose, western North Atlantic) were processed for the lower Maastrichtian (Globotruncana falsostuarti - Gansserina gansseri Planktic Foraminiferal Zone). These data document significant changes in nutrient flux to the sea floor as well as bottom-water oxygenation during this time interval. Parallel to the observed changes in the benthic foraminiferal assemblages the number of inoceramid shells decreases, reflecting also a significant increase in bottom-water oxygenation. We speculate, that these data could reflect the onset of a shift from warmer low-latitude to cooler high-latitude deep-water sources. This speculation will predate the major reorganization of the oceanic circulation resulting in a circulation mode similar to today at the Early/Late Maastrichtian boundary by ~1 Ma and therefore improves our understanding of Late Cretaceous paleoceanography.

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Sites 545 and 547 collectively penetrated 629 m of mid-Cretaceous strata (upper Aptian to upper Cenomanian) off central Morocco during Leg 79 of the Deep Sea Drilling Project. Site 545, at the base of the steep Mazagan Escarpment, records a virtually complete succession of hemipelagic sediments of early late Aptian to middle Cenomanian age. Minor faunal recycling occurred throughout much of the upper Aptian to middle Albian part of the sequence (Cores 55 through 41), reflecting bottom currents along the Mazagan Escarpment. This may be related to the strong upwelling regime and high surface water productivity over Site 545 during the latest Aptian through middle Albian. The upwelling system ceased rather abruptly in this area in late middle Albian time. Recycling of older strata by bottom currents also ceased in the late middle Albian and resulted in a slower average accumulation rate in the upper Albian to middle Cenomanian section of Site 545 (Cores 40 through 28). However, intervals of pebbly claystone conglomerates in Cores 40 and 34 record sporadic instability in the slope adjacent to Site 545. Site 547, located only about 15 km seaward, is situated in a small sub-basin adjacent to the basement block drilled by Site 544. It contains an expanded upper Albian to upper Cenomanian sequence as a result of the numerous conglomeratic intervals throughout much of the section. In contrast to Site 545, the conglomerates were not derived from older strata cropping out on the Mazagan Escarpment; rather, they originated penecontemporaneously from a local unstable slope. A detailed biostratigraphic framework based on planktonic foraminifers is established for the mid-Cretaceous sections of Sites 545 and 547 and a new composite zonal scheme is proposed for the early late Aptian through early late Cenomanian interval. Fifty-five species are recognized and illustrated

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Middle Eocene to Late Oligocene sediments from near the crest (Site 689B, water depth 2080 m) and flank (water depth 2914 m) of the Maud Rise (62°S) have been investigated by coarse fraction analysis and have revealed the following: (1) The middle Eocene (50-40 Ma) was a period of pure carbonate sedimentation, with good preservation of carbonate microfossils. No opal > 40 µm is present. (2) In the late Eocene (40-36.5 Ma) opal fossils (mainly radiolaria, and some diatoms > 40 µm) appeared for the first time. Three maxima in opal sedimentation (Eocene/Oligocene boundary, middle early Oligocene and early/late Oligocene boundary) are separated by increases in carbonate sedimentation. The dissolution of carbonate fossils is strong in the opal-rich layers. Opal sedimentation is attributed to cooling and probably more vigorous atmospheric circulation and increased upwelling. (3) Carbonate dissolution increased with water depth in the Oligocene, whereas in the middle Eocene excellent carbonate preservation in the deeper Site 690B and stronger dissolution in the shallower Site 689B is attributed to different bottom-water characteristics. The middle Eocene bottom water probably was formed by strong evaporation at low latitudes, whereas by the earliest Oligocene formation of Antarctic Bottom Water (AABW) had set in. (4) Current influence, not on top but on the flank of the Maud Rise, could be recorded by means of larger grain sizes of benthonic and planktonic microfossils. (5) Ice-rafted debris was not found. Quartz and other minerals are very rare and not larger than 125 µm and may have been supplied by ice as well as by wind or by deep currents. Mica contents were up to 10 times higher in the middle Eocene on the flank compared to on the crest of the Maud Rise, indicating deep current supply.

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A global compilation of deep-sea isotopic records suggests that Maastrichtian ocean-climate evolution was technically driven. During the early Maastrichtian the Atlantic intermediate-deep ocean was isolated from the Pacific, Indian, and Southern Oceans; deep water formed in the high-latitude North Atlantic and North Pacific. At the early/late Maastrichtian boundary a major reorganization of oceanic circulation patterns occurred, resulting in the development of a thermohaline circulation system similar to that of the modern oceans. A combination of isotopic and plate kinematic data suggests that this event was triggered by the final breaching of tectonic sills in the South Atlantic and the initiation of north-south flow of intermediate and deep water in the Atlantic. The onset of Laramide tectonism during the mid Maastrichtian led to the concurrent draining of major epicontinental seaways. Together, these events caused cooling, increased latitudinal temperature gradients, increased ventilation of the deep ocean, and affected a range of marine biota.