Horizontal spatial and temporal distribution patterns of nearshore larval fish assemblages at a temperate rocky shore     

Rita Borges  Radhouan Ben-Hamadou  M. Alexandra Chícharo  Pedro R  Emanuel J. Gonalves 《Estuarine, Coastal and Shelf Science》2007,71(3-4):412-428

There have been no previous studies of the composition of nearshore larval fish assemblages along the coast of Portugal. We aimed to describe the composition and horizontal distribution patterns of larval fish assemblages and their temporal dynamics near a rocky reef at depths shallower than 13 m (inshore) and at two miles (3.70 km) from shore (offshore), as well as along transects perpendicular to the shoreline, from the reef to 10 miles offshore (18.52 km). Samples were taken using 5 min sub-surface trawls at the rocky shore of the Arrábida Marine Park (W Portugal). A total of 1021 larvae were collected, belonging to 61 taxa inshore and to 29 taxa offshore. Along transects, 626 larvae of 52 taxa were collected. Most larvae belonged to coastal species associated with rocky reefs. Total larval abundance and diversity were higher from May to July, which is consistent with the spawning activity of adults. Diversity and total larval abundance decreased significantly with increasing distance from shore, both in the inshore/offshore comparison and in the transects, where this decrease was evident at a very small spatial scale (within the first mile from the reef). Species assemblages differed in the pattern of distribution, with most species clearly associated to the extreme nearshore. The distribution patterns obtained were independent of the spawning mode of species. Results are discussed in the light of the possible physical mechanisms that can potentially act at the Arrábida Marine Park to facilitate larvae retention and the role of larval behaviour.  相似文献   

On the Use of CloudSat and MODIS Data for Estimating Hurricane Intensity   总被引：2，自引：0，他引：2  

Zhengzhao Luo Stephens  G.L. Emanuel  K.A. Vane  D.G. Tourville  N.D. Haynes  J.M. 《Geoscience and Remote Sensing Letters, IEEE》2008,5(1):13-16

This letter presents preliminary results concerning the use of new observations from the A-Train Constellation for testing a new technique of remotely sensing hurricane intensity from space based on modeling a hurricane as a balanced, convectively neutral vortex. The key observational requirements are simultaneous, accurate measurements of cloud-top height, cloudtop temperature, and cloud profiling information across the center of the storm, although there are ways to bypass the need for cloud-top temperature. In this letter, the Moderate Resolution Imaging Spectroradiometer onboard Aqua provides an estimation of the cloud-top temperature, and the near-simultaneous CloudSat observations provide the essential cloud-top height and cloud profiling information. Initial results indicate that the new technique is a promising method for estimating storm intensity when compared post facto to the best track database. Potential uncertainties and room for further refinement of the technique are discussed.  相似文献   

A quantitative analysis of the prototype [WCL] star CPD-56° 8032     

Paul A. Crowther  Orsola De Marco  M. J. Barlow  P. J. Storey 《Astrophysics and Space Science》1996,238(1):119-123

We present a detailed, quantitative study of the standard [WC10] Wolf-Rayet central star CPD-56^o 8032 based on new high resolution AAT UCLES observations and the Hillier (1990) WR standard model. Our analysis of CPD-56^o 8032 gives the wind properties (T _*=34500K, lg (L/L )=3.8, lg (M/M a^–1)=–5.4,v =225 km s^–1) and chemistry (C/He=0.5, O/He=0.1, by number), the latter suggesting an intimate relationship with the Ovi PN central stars and the PG 1159-035 objects. A comparison between the wind properties of CPD-56^o 8032 and Sk-66^o 40 (WN 10) indicates that low excitation, low wind velocity WR winds are common to both low mass PN central stars (WC sequence) and high mass post-LBV's (WN sequence).  相似文献   

Microstructural evolution of the Seridó Belt, NE-Brazil: the effect of two tectonic events on development of c-axis preferred orientation in quartz     

Mrio Neto Cavalcanti de Araújo  Fernando Csar Alves da Silva  Emanuel Ferraz Jardim de S  Rodney J. Holcombe  Paulo Marcos de Vasconcelos 《Journal of Structural Geology》2003,25(12):2089-2107

The polyphase evolution of the Seridó Belt (NE-Brazil) includes D₁ crust formation at 2.3–2.1 Ga, D₂ thrust tectonics at 1.9 Ga and crustal reworking by D₃ strike-slip shear zones at 600 Ma. Microstructural investigations within mylonites associated with D₂ and D₃ events were used to constrain the tectono-thermal evolution of the belt. D₂ shear zones commenced at deeper crustal levels and high amphibolite facies conditions (600–650 °C) through grain boundary migration, subgrain rotation and operation of quartz c-prism slip. Continued shearing and exhumation of the terrain forced the re-equilibration of high-T fabrics and the switching of slip systems from c-prism to positive and negative a-rhombs. During D₃, enhancement of ductility by dissipation of heat that came from syn-D₃ granites developed wide belts of amphibolite facies mylonites. Continued shearing, uplift and cooling of the region induced D₃ shear zones to act in ductile-brittle regimes, marked by fracturing and development of thinner belts of greenschist facies mylonites. During this event, switching from a-prism to a-basal slip indicates a thermal path from 600 to 350 °C. Therefore, microstructures and quartz c-axis fabrics in polydeformed rocks from the Seridó Belt preserve the record of two major events, which includes contrasting deformation mechanisms and thermal paths.  相似文献   

Impact of land-surface initialization on sub-seasonal to seasonal forecasts over Europe     

Chloé Prodhomme  Francisco Doblas-Reyes  Omar Bellprat  Emanuel Dutra 《Climate Dynamics》2016,47(3-4):919-935

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The structural evolution of George VI sound, Antarctic Peninsula     

R.D. Crabtree  B.C. Storey  C.S.M. Doake 《Tectonophysics》1985,114(1-4)

George VI Sound, 400 km long and between 25 and 90 km wide, separates Alexander Island from the Antarctic Peninsula. The straight parallel sides of its northern section and sub-parallel normal faulting observed in exposed rock on adjacent parts of Alexander Island and Palmer Land indicate a history of rifting. Subglacial topography, revealed through radar sounding of ice thickness in Palmer Land, shows deep areas which owe their presence to two major fault zones parallel to the main N-S trend. One of these is probably the western escarpment of the Palmer Land plateau and the eastern boundary of the rift system. Bedrock relief suggests that transverse block faulting has differentially raised and lowered the mountains on the eastern side of the sound. A seismic profile through George VI Ice Shelf (which occupies most of George VI Sound) confirms that the “W”-shaped cross-section of the bedrock observed by plumb-line at the northern edge of the ice shelf is also found 250 km further south. The shape may be due entirely to glacial erosion, but it is more likely to be a structural feature subsequently glacially modified. These features are consistent with a model of George VI Sound as a region of Tertiary intra-arc extension within the Mesozoic and Cenozoic magmatic arc of the Antarctic Peninsula and Alexander Island.  相似文献   

A semiquantitative explanation of the observed ventisphere phenomenon     

Azmon  Emanuel  Elazar  David 《Mathematical Geosciences》1983,15(5):639-642

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Dilemmas of development in Oceania: the political economy of the Tongan agro-export sector     

Donovan Storey  & Warwick E. Murray 《The Geographical journal》2001,167(4):291-304

This article critically engages with the recent diffusion of the orthodox development model in Oceania and highlights some evolving dilemmas. In particular, it explores the social, economic and ecological tensions arising from economic reforms that are exacerbating the fragility of already vulnerable nation-states and communities. In order to illustrate its arguments, a case study of the impacts of agro-export growth in Tonga is presented. Attention is drawn to the socially inequitable and ecologically unsustainable outcomes of rapid growth in this sector. In analyzing the political economy of the squash pumpkin sector, the authors point to the important role that culture plays in mediating and conditioning development outcomes. Reflecting on the Tongan case, it is argued that to better understand the implications of orthodox developmental reform in the region, research must seek to more explicitly incorporate distributional and ethical analysis.  相似文献   

Die Ausgleichung und Genauigkeit Eines Polygonzuges mit Lagengemäss Ungenauen Anschlusspunkten     

Emanuel Procházka 《Studia Geophysica et Geodaetica》1969,13(2):105-124

Summary In adjusting a bilaterally connected polygonal traverse, whether to positionally accurate or inaccurate points of departure, the mean errors are the problem of primary importance. Hitherto, the mean errors of lengths and angles were chosen; the procedure was such that the weights of both quantities were determined from the mean errors chosen, and this fixed the ratio of the mean errors. This ratio did not change as a result of the adjustment, but the absolute values of the mean errors did. Provided the adjustment was carried out on a polygonal traverse with fixed points of departure, this change did not matter. In the case of ellipses of errors in the points of departure, this change is not permissible, because it would include the change of the semi-axes of the ellipses of errors and, therefore, also of the positional rigidity of the points of departure. The contribution of this paper is in the exact method by which it is possible to compute a coefficientc, pertaining to the mean angular error selected (in the case of positionally inaccurate pointsd), which determines the mean errorm=±e √s (orm=±d √s) of the lengthss. The solution is based on the definition of the mean error of a unit weight founded on the work of deformation. In the calculus of observations, the work of deformation has so far been determined as the deformation work of internal forces from the corrections of the individual quantities after the adjustment is concluded. However, it is possible, as was demonstrated in this paper, to express it as the deformation work of external forces, which act during the adjustment in pointO (Fig. 1) on the auxiliary static system in the shape of a console, and which provide it with the necessary deformation. If the external forces are expressed by means of the tensor of the auxiliary system, the equation for the mean error of the unit weight will provide a relation between this error and the coefficientc, ord. If the mean angular error is selected and if its weight is put equal to one, an equation of the fourth degree is obtained in terms ofc (ord), from which it is possible to compute this coefficient. From the external forces, necessary to produce the deformation of the auxiliary system during its adjustment, the corrections of the individual elements of this system may be determined. If we want to determine the ellipse of errors in one of the polygonal points, it is necessary to investigated the shifts of this point, which occur if the point is acted upon by a unit force first in one and then in another direction, perpendicular to the first. Both shifts represent conjugate radii of the deformation ellipse. From this ellipse we proceed to the ellipse of errors. The general solution is supplemented by a numerical example of adjusting a polygonal traverse with positionally inaccurate points and, for sake of comparison, also by the adjustment of this traverse with positionally accurate points.

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Anschrift: Husova 5, Praha 1-Staré Město  相似文献   

Einfluss der Lagenungenauigkeit von Anschlusspunkten bei Punktbestimmung Durch Richtungseinschneiden     

Emanuel Procházka 《Studia Geophysica et Geodaetica》1967,11(4):397-412

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