Light as a driver of phytoplankton growth and production in the freshwater tidal zone of a turbid estuary   总被引：2，自引：0，他引：2  

Rita B. Domingues  Tnia P. Anselmo  Ana B. Barbosa  Ulrich Sommer  Helena M. Galvo 《Estuarine, Coastal and Shelf Science》2011,91(4):282

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Synthetic Spectra for Carbon Stars from Dynamica Model Atmospheres     

Rita Loidl  Josef Hron  Bernhard Aringer  Susanne Höfner  Uffe G. Jφrgensen 《Astrophysics and Space Science》1997,255(1-2):289-290

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Dust Features of Visually Bright AGB Variables as Seen by ISO and IRAS     

Josef Hron  Rita Loidl  Franz Kerschbaum 《Astrophysics and Space Science》1997,251(1-2):211-214

ISO-SWS spectra of two Mira variables (R Cas and T Dra), taken at two different pulsational phases, are presented. We describe the reduction of the data and the encountered problems. The dust features observed by ISO at different phases and with the Low Resolution Spectrometer of IRAS are compared. We briefly discuss the results in terms of current models for the circumstellar dust shells of AGB variables. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

Synthetic radii and visibilities for pulsating red giants     

Josef Hron  Walter Nowotny  Rita Gautschy-Loidl  Susanne Höfner 《Astrophysics and Space Science》2003,286(1-2):213-218

We present synthetic radii and visibilities in the IR, based on hydrostatic and dynamic model atmospheres of carbon stars. The differences between these two sets of input models and to uniform disc models are discussed and compared to the expected capabilities of the VLTI. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The western Durkan Complex (Makran Accretionary Prism,SE Iran): A Late Cretaceous tectonically disrupted seamounts chain and its role in controlling deformation style     

Edoardo Barbero  Luca Pandolfi  Morteza Delavari  Asghar Dolati  Emilio Saccani  Rita Catanzariti  Valeria Luciani  Marco Chiari  Michele Marroni 《地学前缘(英文版)》2021,12(3):101106

The Durkan Complex is a key tectonic element of the Makran accretionary prism (SE Iran) and it has been interpreted as representing a continental margin succession. We present here a multidisciplinary study of the western Durkan Complex, which is based on new geological, stratigraphic, biostratigraphic data, as well as geochemical data of the volcanic and meta-volcanic rocks forming this complex. Our data show that this complex consists of distinct tectonic slices showing both non-metamorphic and very low-grade metamorphic deformed successions. Stratigraphic and biostratigraphic data allow us to recognize three types of successions. Type-I is composed by a Coniacian – early Campanian pelagic succession with intercalation of pillow lavas and minor volcaniclastic rocks. Type-II succession includes a volcanic sequence passing to a volcano-sedimentary sequence with Cenomanian pelagic limestones, followed by a hemipelagic sequence. This succession is characterized by abundant mass-transport deposits. Type-III succession includes volcanic and volcano-sedimentary sequences, which are stratigraphically covered by a Cenomanian platform succession. The latter is locally followed by a hemipelagic sequence. The volcanic rocks in the different successions show alkaline geochemical affinity, suggesting an origin from an oceanic within-plate setting. Our new results indicate that the western Durkan Complex represents fragments of seamounts tectonically incorporated in the Makran accretionary wedge during the latest Late Cretaceous–Paleocene. We propose that incorporation of seamounts in the frontal prism caused a shortening of the whole convergent margin and possibly contributed to controlling the deformation style in the Makran Accretionary Wedge during Late Cretaceous–Paleocene times.  相似文献   

Investigation of the climate-driven periodicity of shallow groundwater level fluctuations in a Central-Eastern European agricultural region     

Tamás Garamhegyi  József Kovács  Rita Pongrácz  Péter Tanos  István Gábor Hatvani 《Hydrogeology Journal》2018,26(3):677-688

The distribution and amount of groundwater, a crucial source of Earth’s drinking and irrigation water, is changing due to climate-change effects. Therefore, it is important to understand groundwater behavior in extreme scenarios, e.g. drought. Shallow groundwater (SGW) level fluctuation under natural conditions displays periodic behavior, i.e. seasonal variation. Thus, the study aims to investigate (1) the periodic behavior of the SGW level time series of an agriculturally important and drought-sensitive region in Central-Eastern Europe – the Carpathian Basin, in the north-eastern part of the Great Hungarian Plain, and (2) its relationship to the European atmospheric pressure action centers. Data from 216 SGW wells were studied using wavelet spectrum analysis and wavelet coherence analyses for 1961–2010. Locally, a clear relationship exists between the absence of annual periodic behavior in the SGW level and the periodicity of droughts, as indicated by the self-calibrating Palmer Drought Severity Index and the Aridity Index. During the non-periodic intervals, significant drops in groundwater levels (average 0.5 m) were recorded in 89% of the wells. This result links the meteorological variables to the periodic behavior of SGW, and consequently, drought. On a regional scale, Mediterranean cyclones from the Gulf of Genoa (northwest Italy) were found to be a driving factor in the 8-yr periodic behavior of the SGW wells. The research documents an important link between SGW levels and local/regional climate variables or indices, thereby facilitating the necessary adaptation strategies on national and/or regional scales, as these must take into account the predictions of drought-related climatic conditions.  相似文献   

The political ecology of territoriality: territorialities in farmer–herder relationships in Northern Ghana     

Rita Yembilah  Miriam Grant 《GeoJournal》2014,79(3):385-400

Fulani herder and farmer relationships in West Africa have always been troublesome as a result of farmers’ fundamental rejection of the herders’ inroads into their areas and also because of increased competition for available resources. In countries such as Ghana, local and even national campaigns have been launched to expel the herders but they persist. This case-study which utilised interviews and group discussions involving farmers and herders, sought to understand the dynamics and subtleties of herders’ resilience in an environment where natural resource access and use rights are tied to common property principles and where herders have no enshrined land and resource rights. Using territoriality as the analytical capsule, we found that the herders’ persistence is related to mainly non-territoriality where the goal is to influence relationships and resource access but not control area. Categorising their non-territorial expression into persuasive and aggressive forms, we provide a new platform for deconstructing farmer-herder relationships in the West African sub-region.  相似文献   

Stochastic Simulation Model for the Spatial Characterization of Lung Cancer Mortality Risk and Study of Environmental Factors     

Ana Rita Oliveira  Cristina Branquinho  Maria Pereira  Amílcar Soares 《Mathematical Geosciences》2013,45(4):437-452

This paper presents a study in which the lung cancer risk in males was characterized based on a simulation model of mortality rates. Block sequential simulation of mortality rates, measured in counties of different sizes, was implemented and applied to a normal grid of continental Portugal with high spatial resolution. The uncertainty in the mortality rate measurements, directly related to differences in the population size of each county, was integrated in a block direct sequential simulation through Poisson kriging of local means and variances. Three age groups were examined: 50–59, 60–69, and 70–79 years. After the continuous geographic patterns of lung cancer risk were obtained, factors potentially associated with the main areas of risk were analyzed for southern Portugal. Thus, a defined class of land use and dry weather events, related to airborne particulate matter, were found to be associated with high-risk areas, resulting in high local spatial correlation patterns in all three age groups.  相似文献   

Composition and origin of nodules from the ≈20 ka Pomici di Base (PB)-Sarno eruption of Mt. Somma — Vesuvius, Italy     

Rita Klébesz  Robert J. Bodnar  Benedetto De Vivo  Kálmán T?r?k  Annamaria Lima  Paola Petrosino 《Central European Journal of Geosciences》2012,4(2):324-337

Nodules (coarse-grain ??plutonic?? rocks) were collected from the ca. 20 ka Pomici di Base (PB)-Sarno eruption of Mt. Somma-Vesuvius, Italy. The nodules are classified as monzonite-monzogabbro based on their modal composition. The nodules have porphyrogranular texture, and consist of An-rich plagioclase, K-feldspar, clinopyroxene (ferroan-diopside), mica (phlogopite-biotite) ± olivine and amphibole. Aggregates of irregular intergrowths of mostly alkali feldspar and plagioclase, along with mica, Fe-Ti-oxides and clinopyroxene, in the nodules are interpreted as crystallized melt pockets. Crystallized silicate melt inclusions (MI) are common in the nodules, especially in clinopyroxenes. Two types of MI have been identified. Type I consists of mica, Fe-Ti-oxides and/or dark green spinel, clinopyroxene, feldspar and a vapor bubble. Volatiles (CO₂, H₂O) could not be detected in the vapor bubbles by Raman spectroscopy. Type II inclusions are generally lighter in color and contain subhedral feldspar and/or glass and several opaque phases, most of which are confirmed to be oxide minerals by SEM analysis. Some of the opaque-appearing phases that are below the surface may be tiny vapor bubbles. The two types of MI have different chemical compositions. Type I MI are classified as phono-tephrite ?? tephri-phonolite ?? basaltic trachy-andesite, while Type II MI have basaltic composition. The petrography and MI geochemistry led us to conclude that the nodules represent samples of the crystal mush zone in the active plumbing system of Mt. Somma-Vesuvius that were entrained into the upwelling magma during the PB-Sarno eruption.  相似文献   

Ground motion simulations of the SW Iberia margin: rupture directivity and earth structure effects   总被引：1，自引：0，他引：1  

M. Bezzeghoud  J. F. Borges  B. Caldeira 《Natural Hazards》2013,69(2):1229-1245

In this study, we focus on the region between Gorringe Bank and the Horseshoe Fault located in the SW Iberia margin, which is believed to be the site of the great 1755 earthquake. We model ground motions using an extended source located near the Horseshoe scarp to generate synthetic waveforms using a wave propagation code, based on the finite-difference method. We compare the simulated waveforms, for the Algarve Basin and the Lower Tagus Valley Basin (Portugal), using a 3-D velocity model down to the Moho discontinuity with a simple 1-D layered model. The radiated wave field is very sensitive to the velocity model and a small number of source parameters, in particular, the rupture directivity. The rupture directivity, the strike direction and the fault dimensions are critical to the azimuthal distribution of the maximum amplitude oscillations. We show that the use of a stratified 1-D model is inappropriate in SW Iberia, where sources are located in the oceanic domain and receivers in the continental domain. The crustal structure varies dramatically along the ray paths, with large-scale heterogeneities of low or high velocities. Moreover, combined with the geometric limitations inherent to the region, a strong trade-off between several parameters is often observed; this is particularly critical when studying moderate magnitude earthquakes (M < 6), which constitute the bulk of the seismic catalogue in SW Iberia.  相似文献