Criação de jacaré.

Apresentação; Origem; Reprodução; Espécies; Alimentação; Filhotes; Características; Instalação; Ninho; Utilidade.bitstream/item/98420/1/CPAF-AP-1989-Criacao-jacare.pdfApostila

Mesozoic spreading kinematics: consequences for Cenozoic Central and Western Mediterranean subduction

The highly complex tectonics of Central and Western Mediterranean subduction are well documented, but there is significant debate about the responsible dynamics. The motions of the main plates, Africa including Adria, Europe and Iberia, imposed initial and boundary conditions on the evolution of subduction that are often not considered. To quantitatively evaluate these conditions, we make a set of reconstructions from Mesozoic opening through Cenozoic closing of the Alpine Tethys, using main-plate kinematic data from several authors. Geologic and tectonic information are only added to constrain the location of the break-up boundary and a single plate-margin rearrangement at the end of the opening phase. Otherwise, the plates remain undeformed. This rigid-plate approach illustrates the context in which surface deformation and subduction occurred and provides estimates (with uncertainties) of the amount of material that should be accounted for in orogens or documented seismically in the mantle. Full tectonic reconstructions should satisfy such constraints. Opening led to alternating domains of predominantly oceanic lithosphere formed by normal spreading and domains dominated by transform motion, floored mainly by extended continental lithosphere. The transform domain structures provide logical decoupling zones to allow Penninic, Ligurian and Pyrenean basins to start subducting independently. The complex buoyancy in the transform domain linking Ligurian and Penninic basins, and obliquity between directions of opening and closing may account for a number of the oceanic basins and continental slivers often invoked to explain Alpine geology. The significant proportion of continental lithosphere in the Alboran would have favoured delamination of mantle lithosphere over subduction. The almost completely subducted Penninic slab obstructed subduction of the Ligurian domain in the direction of Africa-Europe convergence, possibly forcing the rollback of the Appeninic/Calabrian trenc

Low-power 6-bit 1-GS/s two-channel pipeline ADC with open-loop amplification using amplifiers with local-feedback

IEEE International Symposium on Circuits and Systems, pp. 2258 – 2261, Seattle, EUAA low-power 1.2 V 6-bit 1-GS/s time-interleaved pipeline ADC designed in 130 nm CMOS is described. It is based on a new 2-channel 1.5-bit MDAC that performs openloop residue amplification using a shared amplifier employing local-feedback. Time mismatches between channels are highly attenuated, simply by using two passive front-end Sample-and-Hold circuits, with dedicated switch-linearization control circuits, driven by a single clock phase. Simulated results of the ADC achieve 5.35-bit ENOB, with 20 mW and without requiring any gain control/calibration scheme

Thorotrast Related Hepatic Malignancies. Two Case Reports

Os A.A apresentam dois casos clínicos de tumores hepáticos associados ao torotraste, dois colangiocarcinomas, observados numa enfermaria de Medicina Interna de um hospital de Lisboa. É feito um comentário sobre o efeito nefasto das radiações ionizantes em geral sobre o organismo humano, particularizando os efeitos do torotraste. Comenta-se, ainda, o prolongado tempo de latência que existiu nestes dois casos, bem como o facto de, provavelmente, estarmos perante os últimos casos de tumores induzidos pelo torotraste

Multivariate statistical appraisal of regional susceptibility to induced seismicity: application to the Permian Basin, SW United States

Induced earthquake sequences are typically interpreted through causal triggering mechanisms. However, studies of causality rarely consider large regions and why some regions experiencing similar anthropogenic activities remain largely aseismic. Therefore, it can be difficult to forecast seismic hazard at a regional scale. In contrast, multivariate statistical methods allow us to find the combinations of factors that correlate best with seismicity, which can help form the basis of hypotheses that can be subsequently tested with physical models. Whilst strong correlations do not necessarily equate to causality, such a statistical approach is particularly important for large regions with newly emergent seismicity comprising multiple distinct clusters and multi-faceted industrial operations. Recent induced seismicity in the Permian Basin provides an excellent test-bed for multivariate statistical analyses because the main causal industrial and geological factors driving earthquakes in the region remain highly debated. Here, we use logistic regression to retrospectively predict the spatial variation of seismicity across the western Permian Basin. We reproduce the broad distribution of seismicity using a combination of both industrial and geological factors. Our model shows that the proximity to neotectonic faults west of the Delaware Basin is the most important factor that contributes to induced seismicity. The second-most important factor is salt-water disposal at shallow depths, with hydraulic fracturing playing a less dominant role. The higher tectonic stressing, together with a poor correlation between seismicity and large-volume deep salt-water disposal wells indicates a very different mechanism of induced seismicity compared to that in Oklahoma

Cold Regime Interannual Variability of Primary and Secondary Producer Community Composition in the Southeastern Bering Sea

Variability of hydrographic conditions and primary and secondary productivity between cold and warm climatic regimes in the Bering Sea has been the subject of much study in recent years, while interannual variability within a single regime and across multiple trophic levels has been less well-documented. Measurements from an instrumented mooring on the southeastern shelf of the Bering Sea were analyzed for the spring-to-summer transitions within the cold regime years of 2009–2012 to investigate the interannual variability of hydrographic conditions, primary producer biomass, and acoustically-derived secondary producer and consumer abundance and community structure. Hydrographic conditions in 2012 were significantly different than in 2009, 2010, and 2011, driven largely by increased ice extent and thickness, later ice retreat, and earlier stratification of the water column. Primary producer biomass was more tightly coupled to hydrographic conditions in 2012 than in 2009 or 2011, and shallow and mid-column phytoplankton blooms tended to occur independent of one another. There was a high degree of variability in the relationships between different classes of secondary producers and hydrographic conditions, evidence of significant intra-consumer interactions, and trade-offs between different consumer size classes in each year. Phytoplankton blooms stimulated different populations of secondary producers in each year, and summer consumer populations appeared to determine dominant populations in the subsequent spring. Overall, primary producers and secondary producers were more tightly coupled to each other and to hydrographic conditions in the coldest year compared to the warmer years. The highly variable nature of the interactions between the atmospherically-driven hydrographic environment, primary and secondary producers, and within food webs underscores the need to revisit how climatic regimes within the Bering Sea are defined and predicted to function given changing climate scenarios

Thermochemical interpretation of one-dimensional seismic reference models for the upper mantle: Evidence for bias due to heterogeneity

A 1-D reference model for the mantle that is physically meaningful would be invaluable both in geodynamic modelling and for an accurate interpretation of 3-D seismic tomography. However, previous studies have shown that it is difficult to reconcile the simplest possible 1-D physical model—1300°C adiabatic pyrolite—with seismic observations. We therefore generate a set of alternative 1-D thermal and chemical mantle models, down to 900 km depth, and compare their properties with seismic data. We use several different body and surface wave data sets that provide complementary constraints on mantle structure. To assess the agreement between our models and seismic data, we take into account the large uncertainties in both the elastic/anelastic parameters of the constituent minerals, and the thermodynamic procedures for calculating seismic velocities. These uncertainties translate into substantial differences in seismic structure. However, in spite of such differences, subtle trends remain. We find that models which attain (1) higher velocity gradients between 250 and 350 km; (2) higher velocity gradients in the lower transition zone; and (3) higher average velocities immediately beneath the 660-discontinuity, than 1300°C adiabatic pyrolite—either via a temporary shift to lower temperatures, and/or a change to a seismically faster chemical composition—provide a significantly better fit to the seismic data than adiabatic pyrolite. This is compatible with recent thermochemical dynamic models by Tackley et al. in which average thermal structure is smooth and monotonous, but average chemical structure deviates substantially from pyrolite above, in, and below the transition zone. Our results suggest that 1-D seismic reference models are being systematically biased by a complex 3-D chemical structure. This bias should be taken into account when attempting quantitative interpretation of seismic anomalies, since those very anomalies contribute to the 1-D average signa

Mantle wedge temperatures and their potential relation to volcanic arc location

The mechanisms underpinning the formation of a focused volcanic arc above subduction zones are debated. Suggestions include controls by: (i) where the subducting plate releases water, lowering the solidus in the overlying mantle wedge; (ii) the location where the mantle wedge melts to the highest degree; and (iii) a limit on melt formation and migration imposed by the cool shallow corner of the wedge. Here, we evaluate these three proposed mechanisms using a set of kinematically-driven 2D thermo-mechanical mantle-wedge models in which subduction velocity, slab dip and age, overriding-plate thickness and the depth of decoupling between the two plates are systematically varied. All mechanisms predict, on the basis of model geometry, that the arc-trench distance, D, decreases strongly with increasing dip, consistent with the negative D-dip correlations found in global subduction data. Model trends of sub-arc slab depth, H, with dip are positive if H is wedge-temperature controlled and overriding-plate thickness does not exceed the decoupling depth by more than 50 km, and negative if H is slab-temperature controlled. Observed global H-dip trends are overall positive. With increasing overriding plate thickness, the position of maximum melting shifts to smaller H and D, while the position of the trenchward limit of the melt zone, controlled by the wedge's cold corner, shifts to larger H and D, similar to the trend in the data for oceanic subduction zones. Thus, the limit imposed by the wedge corner on melting and melt migration seems to exert the first-order control on arc position

Fragmento de floresta de transição na zona urbana do Município de Macapá: propostas de estudos e aproveitamento.

bitstream/item/81067/1/AP-2012-Fragmento-floresta-documentos-75.pd