974 resultados para Strenght in the lower members


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Cystadenomas are a rare, painless, and slow-growing benign epithelial tumor of the salivary gland. This article describes the case of a papillary cystadenoma in the lower lip of a 46-year-old man. The lesion was removed using a carbon dioxide laser, and there were no signs of recurrence 1 year postoperatively.

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In the first decades of the 20th century, aerological observations were for the first time performed in tropical regions. One of the most prominent endeavours in this respect was ARTHUR BERSON’s aerological expedition to East Africa. Although the main target was the East African monsoon circulation, the expedition provided also other insights that profoundly changed meteorology and climatology. BERSON observed that the tropical tropopause was much higher and colder than that over midlatitudes. Moreover, westerly winds were observed in the lower stratosphere, apparently contradicting the high-altitude equatorial easterly winds that were known since the Krakatoa eruption (‘‘Krakatoa easterlies’’). The puzzle was only resolved five decades later with the discovery of the Quasi-Biennial Oscillation (QBO). In this paper we briefly summarize the expedition of BERSON and review the results in a historical context and in the light of the current research. In the second part of the paper we re-visit BERSON’s early aerological observations, which we have digitized. We compare the observed wind profiles with corresponding profiles extracted from the ‘‘Twentieth Century Reanalysis’’, which provides global three-dimensional weather information back to 1871 based on an assimilation of sea-level and surface pressure data. The comparison shows a good agreement at the coast but less good agreement further inland, at the shore of Lake Victoria, where the circulation is more complex. These results demonstrate that BERSON’s observations are still valuable today as input to current reanalysis systems or for their validation.

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A common finding in time psychophysics is that temporal acuity is much better for auditory than for visual stimuli. The present study aimed to examine modality-specific differences in duration discrimination within the conceptual framework of the Distinct Timing Hypothesis. This theoretical account proposes that durations in the lower milliseconds range are processed automatically while longer durations are processed by a cognitive mechanism. A sample of 46 participants performed two auditory and visual duration discrimination tasks with extremely brief (50-ms standard duration) and longer (1000-ms standard duration) intervals. Better discrimination performance for auditory compared to visual intervals could be established for extremely brief and longer intervals. However, when performance on duration discrimination of longer intervals in the 1-s range was controlled for modality-specific input from the sensory-automatic timing mechanism, the visual-auditory difference disappeared completely as indicated by virtually identical Weber fractions for both sensory modalities. These findings support the idea of a sensory-automatic mechanism underlying the observed visual-auditory differences in duration discrimination of extremely brief intervals in the millisecond range and longer intervals in the 1-s range. Our data are consistent with the notion of a gradual transition from a purely modality-specific, sensory-automatic to a more cognitive, amodal timing mechanism. Within this transition zone, both mechanisms appear to operate simultaneously but the influence of the sensory-automatic timing mechanism is expected to continuously decrease with increasing interval duration.

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Deep Sea Drilling Project Site 563, located on the west flank of the northern Mid-Atlantic Ridge, recovered a long Miocene section from which magnetostratigraphic and isotopic stratigraphy are available. Quantitative analyses of calcareous nannofossil assemblages have been performed in the Lower and Middle Miocene sediments from Site 563. The abundance patterns of the identified species allow us to determine several bioevents for this time interval. The recognized biohorizons, related to the available magnetostratigraphy, provide new data on the biostratigraphic value of many species and on the synchroneity of the events over a wide geographic area. Relations with the oxygen isotope stratigraphy are also reported. Sphenolith distribution is examined in particular detail due to their biostratigraphic importance in the Early Miocene. In particular the recently described species Sphenolithus procerus, Sphenolithus tintinnabulum and Sphenolithus multispinatus can be useful to subdivide the Lower Miocene zones NN2 and NN3. A large variety of Reticulofenestra pseudoumbilicus has been identified within zones NN6 and NN7.

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The drift of 52 icebergs tagged with GPS buoys in the Weddell Sea since 1999 has been investigated with respect to prevalent drift tracks, sea ice/iceberg interaction, and freshwater fluxes. Buoys were deployed on small- to medium-sized icebergs (edge lengths ? 5 km) in the southwestern and eastern Weddell Sea. The basin-scale iceberg drift of this size class was established. In the western Weddell Sea, icebergs followed a northward course with little deviation and mean daily drift rates up to 9.5 ± 7.3 km/d. To the west of 40°W the drift of iceberg and sea ice was coherent. In the highly consolidated perennial sea ice cover of 95% the sea ice exerted a steering influence on the icebergs and was thus responsible for the coherence of the drift tracks. The northward drift of buoys to the east of 40°W was interrupted by large deviations due to the passage of low-pressure systems. Mean daily drift rates in this area were 11.5 ± 7.2 km/d. A lower threshold of 86% sea ice concentration for coherent sea ice/iceberg movement was determined by examining the sea ice concentration derived from Special Sensor Microwave Imager (SSM/I) and Advanced Microwave Scanning Radiometer for EOS (AMSR-E) satellite data. The length scale of coherent movement was estimated to be at least 200 km, about half the value found for the Arctic Ocean but twice as large as previously suggested. The freshwater fluxes estimated from three iceberg export scenarios deduced from the iceberg drift pattern were highly variable. Assuming a transit time in the Weddell Sea of 1 year, the iceberg meltwater input of 31 Gt which is about a third of the basal meltwater input from the Filchner Ronne Ice Shelf but spreads across the entire Weddell Sea. Iceberg meltwater export of 14.2 × 103 m3 s?1, if all icebergs are exported, is in the lower range of freshwater export by sea ice.

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We report, numerically and in graphical form, meaured tritium concentrations from five hydrographic stations in the North Atlantic. Fairly homogeneous concentrations are observed in a surface layer typically 400 m deep. In the thermocline, concentrations decrease steadily down to the sigma-theta = 27.3 density horizon, and are more variable further down. The tritium in the lower part of the thermocline originates from the Subarctic Intermediate Water and the Mediterranean Water. There is a relative tritium maximum associated with the Mediterranean Water on the easternmost station of the section. In the deep water (sigma-theta > 27.8), concentrations east of the Midatlantic Ridge are close to the limit of detection down to 2500m, and undetectable further down, while west of the ridge tritium is found throughout the water column. The deep water tritium is associated with the deep-water advective cores of Arctic origin. The present tritium data can serve as northern boundary values in attempts to use tritium in studies of the North Atlantic main thermocline dynamics. The present data together with data from the literature point to a general division of the North Atlantic main thermocline into two layers separated by an isopycnal surface near sigma-theta = 27.3.

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A micropaleontological study of planktonic assemblages on the partially laminated sapropel S5 (late Pleistocene, marine isotope stage (MIS) 5e) was performed in two piston cores from Urania Basin area (eastern Mediterranean, west of Crete): UM94PC16 and UM94PC31 recovered during a PALEOFLUX Project Cruise. The abundance of Florisphaera profunda indicates the development of a deep chlorophyll maximum (DCM) before the anoxic condition at bottom were established, whereas patterns of upper photic zone coccoliths suggest extreme oligotrophy in surface water. The short appearance of Globorotalia scitula and the presence of Globigerinoides ruber in the lower part of sapropel testify to a thermal stratification, also recorded by changes in primary producers. During G. scitula occurrence, diatoms, mainly represented by Pseudosolenia calcar-avis, appear and bloom because of their capability in using nutrients from DCM. Scanning electron microscope analyses performed on selected intervals from UM94PC16 show that the sapropel is organized in microlaminae mostly composed by siliceous microfossils. In particular, sapropel S5 could be related to an enhanced nutrient availability in the lower-middle part of the photic zone, stratified conditions, and a higher continental input.

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Phytoplankton of a surface strongly desalinated water lens was investigated on the basis of materials collected during Cruise 57 of R/V Akademik Mstislav Keldysh in September 2007. The lens with salinity <18 psu had area of ca. 19000 sq. km and was located in the northwestern part of the Kara Sea near the eastern coast of Novaya Zemlya. It was a specific biotope that had been isolated from surrounding waters for more than three months. In the investigated area 66 algae species were identified. The maximal species diversity was found in the upper layers of the desalinated lens, where species number was 1.5 to 3 times higher than in other parts of the water column. Phytoplankton abundance in the upper layers of the lens was 1.5 to 4.5 times higher than in its lower part and generally higher than below the picnocline. Diatoms were the most abundant group in the upper layers of the lens, while flagellates dominated in the subpicnocline part of the water column. Maximal values of phytoplankton biomass were observed everywhere in the upper layers of the lens, where they were 1.2 to 3.7 times higher than in the lower part of the lens and 1.3 to 7.2 times higher than in the layer below the picnocline. Dinoflagellates generally gave the most contribution to total phytoplankton biomass. Phytoplankton of the desalinated surface lens in the northwestern part of the Kara Sea by its composition and quantitative parameters had the nearest resemblance to a phytocenosis that we observed two weeks later at a shallow desalinated shelf closely adjacent to the Ob estuary.

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The calcareous nannofossil assemblages of Ocean Drilling Program Hole 963D from the central Mediterranean Sea have been investigated to document oceanographic changes in surface waters. The studied site is located in an area sensitive to large-scale atmospheric and climatic systems and to high- and low-latitude climate connection. It is characterized by a high sedimentation rate (the achieved mean sampling resolution is <70 years) that allowed the Sicily Channel environmental changes to be examined in great detail over the last 12 ka BP. We focused on the species Florisphaera profunda that lives in the lower photic zone. Its distribution pattern shows repeated abundance fluctuations of about 10-15%. Such variations could be related to different primary production levels, given that the study of the distribution of this species on the Sicily Channel seafloor demonstrates the significant correlation to productivity changes as provided by satellite imagery. Productivity variations were quantitatively estimated and were interpreted on the basis of the relocation of the nutricline within the photic zone, led by the dynamics of the summer thermocline. Productivity changes were compared with oceanographic, atmospheric, and cosmogenic nuclide proxies. The good match with Holocene master records, as with ice-rafted detritus in the subpolar North Atlantic, and the near-1500-year periodicity suggest that the Sicily Channel environment responded to worldwide climate anomalies. Enhanced Northern Hemisphere atmospheric circulation, which has been reported as one of the most important forcing mechanisms for Holocene coolings in previous Mediterranean studies, had a remarkable impact on the water column dynamics of the Sicily Channel.

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1. Late glacial and postglacial sediments from three former lakes in the Lake Garda area (Southern Alps) were investigated. 2. The pollen diagram from Bondone (1550 m) shows an older phase rich in NAP. A younger one corresponds with the Younger Dryas time according to two radiocarbon determinations. In the Preboreal no climatic deterioration could be found. 3. At first plants, which are nowadays typical for snow-ground, pioneer and dwarf shrub associations, immigrated into the surroundings of Bondone. In Alleröd times larch and pine appeared as the first trees. At the beginning of the Preboreal dense forest existed in that region. During the Alleröd timber line was at about 1500 m. 4. In the pollen diagrams from Saltarino (194 m) and Fiavè (654 m) an oldest period rich in NAP is followed by two stadial and two interstadial phases. Tree birches and larches immigrated during the oldest interstadial phase. 5. In the case of Saltarino and Fiavè only a preliminary dating could be made. A correlation seems to be possible with diagrams published by Zoller as well as with the diagram of Bondone. Discrepances in dating, which arise then, are discussed. According to the two possibilities of dating the youngest stadial is synchronous either with the so-called Piottino stadial or the Younger Dryas time. Consequently the oldest interstadial phase of Saltarino corresponds either with the Bölling or with a pre-Bölling interstadial. The last possibility seems to be more probable. 6. In the southern part of the Lake Garda area reforestation was preceded by a long shrub phase mainly with Juniperus. At about 650 m there was a period with Pinus mugo and only with a small amount of Juniperus before reforestation. A phase with Betula nana well known from areas north of the Alps could nowhere be found. 7. In the area under study larch appeared as the first tree. Lateron it has been the most important constituent of the forests near timber line. Birch, which plays an important role as a pioneer tree in Denmark - for instance at the transition of the pollen zones III/IV - as well as in Southern Germany during Bölling time, was of less importance at the southern border of the Alps. In that area the spreading of Pinus occurred very early causing dense forests. 8. During the last stadial phase (probably Younger Dryas time) dense forests with Pinus and Larix existed at 650 m. In the lower part of the Lake Garda area, however, both thermophilous trees as Quercus and herbs frequently occurred. This leads to the conclusion that during this time tree growth was limited by dryness in lower altitudes of the border of the Southern Alps. Pinus and Juniperus, however, do not show higher values in this period, a fact which cannot yet be explained. 9. A list of plants, which were found in the sediments, is compiled. Helodium lanatum, Dictamnus albus, Mercurialis cf. ovata, Buxus, Cerinthe cf. minor, Onosma, Anthericum and Asphodelus albus are findings, which are of special interest for the history of the flora of that region.

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Based on discrete samples, we report new high-resolution records of the ~185 kyr Iceland Basin (IB) geomagnetic excursion from Ocean Drilling Project (ODP) Site 1063 on the Bermuda Rise (sedimentation rate 32 cm/kyr) and from ODP Site 983 in the far North Atlantic (sedimentation rate 18 cm/kyr). Two records from Holes 1063A and 1063B are very consistent, and provide the highest resolution of the detailed field behaviour during the IB excursion obtained so far. Inclination records from Holes 983B and 983C in the far North Atlantic are also very consistent, whereas declination anomalies deviate more notably. The pseudo-Thellier (PT) technique was applied along with more conventional palaeointensity proxies (NRM/ARM and NRM/kappa) to recover relative palaeointensity (RPI) estimates from Hole 1063A and Hole 983B. As expected, these proxies indicate that the field intensity generally dropped at both sites during the IB excursion, but also that the history of RPI from the two sites is different. VGPs from Site 1063 indicate that the field at this location experienced some stop-and-go behaviour between patches of intense vertical flux over North America and the tip of South America, areas which coincide fairly well with patches of preferred transitional VGP clustering from reversals and zones of high seismic velocity in the lower mantle. Changes in RPI at this location were generally gradual, possibly due to the proximity of these flux patches, and the first period of VGP-clustering over North America was accompanied by a conspicuous increase in RPI. VGPs from Site 983 track along a different path, and the associated RPI changes are very abrupt and completely synchronous with the onset and termination of the excursion. The differing VGP paths from Sites 1063 and 983 indicate that the global field structure during the IB excursion was not dominated by a single dipole.

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Within the generally oligotroph Arctic marine environment river outlets are favoured by many planktonic and benthic organisms due to their high input of organic carbon. The retention of pelagic larvae within nursery grounds and/or the ability to return to their parental grounds prior to settlement is one important factor for the persistence of benthic communities in such river influenced areas. The southern Kara Sea is strongly controlled by high freshwater inputs from the Ob and Yenisei Rivers, which create a pronounced bi-layered pycnocline with a warm fresh/brackish water layer on top and a cold high saline marine layer below. The dispersal of five meroplanktonic species and settled juveniles (the brittle star Ophiocten sericeum, and the polychaetes Micronephtys minuta, Nereimyra aphroditoides, Phyllodoce groenlandica and Prionospio cirrifera) in relation to the adult distribution patterns was investigated. For all apart from P. cirrifera the highest densities of larvae were found in the upper brackish water layer. To assess size-at-settlement, the body sizes of larvae and newly settled juveniles were estimated and compared. Dispersal patterns ranged from virtually no adaption to river run-off as in the common, stenohaline O. sericeum and M. minuta (7 ind./m**3, 459 µm) to local retention as in N. aphroditoides (7 ind./m**3, 541 µm) and P. groenlandica (0.5 ind./m**3, 1121 µm) retained by horizontal eddies created by the outflow. Adults of P. cirrifera, which were exclusively restricted to the estuary of the Yenisei River, showed a well adapted reproductive behaviour to ensure a high retention potential of their progenies. The larvae (1.5 ind./m**3, 1513 µm) were only present in the lower water layers, most probably taking advantage of the prevailing near bottom counter current retaining them within their hatching areas.

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Dinoflagellate cysts were recovered throughout the Paleogene succession of Hole 647A, which contains an almost complete deep-water record of early Eocene through early late Oligocene sedimentation in the Labrador Sea. Dinoflagellate cyst biostratigraphy is in general accord with that provided by other microfossil groups and is consistent with a lower Eocene age, as determined by nannofossils, for basal sediments in Hole 647A. These sediments overlie oceanic crust of Chron 24 age. Dinocyst assemblages indicate outer neritic to oceanic conditions throughout, although the persistent occurrence of Wetzeliellaceae specimens in the lower Eocene suggests a greater influence from shelf environments during this time. Lower Eocene dinocyst assemblages are similar to coeval assemblages from the Rockall Plateau, but those from the middle to upper Eocene have mixed affinities and may be related to the intensification of the proto-Gulf Stream from middle Eocene time. Oligocene dinocyst assemblages suggest the influence of both arctic and North Atlantic wate rmasses at this site. The presence of protoperidineacean species in the upper Eocene and Oligocene may indicate increased availability of nutrients, perhaps related to increased upwelling or the effects of water-mass mixing. Productive samples are dominated by dinocysts and acritarchs, while sporomorphs are represented mainly by bisaccate pollen. Preservational differences within samples may reflect mixing of penecontemporaneous dinocyst populations during the Eocene, and all samples examined may have a considerable allochthonous component. Variability in relative abundance of many species during the Eocene may be related to fluctuating water-mass properties. A total 175 dinocyst and acritarch taxa were recorded from 53 productive samples from the Paleogene. Only one Paleogene sample was barren of palynomorphs. Of three Miocene samples processed, all were barren.

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In the collective monograph results of geological and geophysical studies in the Tadjura Rift carried out by conventional outboard instruments and from deep/sea manned submersibles "Pisces" in winter 1983-1984 are reported. Main features of rift tectonics, geology, petrology, and geochemistry of basalts from the rift are under consideration. An emphasis is made on lithology, stratigraphy, and geochemistry of bottom sediments. Roles of terrigenous, edafogenic, biogenic, and hydrothermal components in formation of bottom sediments from the rift zone are shown.

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After death of benthic and planktic foraminifera their tests intensive dissolve in sediments of the upper sublittoral zone (depth 30-60 m) in the highest productivity area of surface water in the northern Peruvian region. Dissolution of fine pelitic ooze is more intensive than of sandy sediments. Rate of dissolution is lower in the lower sublittoral zone (60-200 m) than in the upper part of the zone. Within the upper bathyal zone (300-500 m) dissolution decreases and results to accumulation of carbonate test in this zone. Benthic tests are more abundant than planktic ones. Very poor species composition and a peculiar set of species are characteristic of foraminiferal assemblages found in the sublittoral and upper bathyal zones along the Peruvian coast.