Hawaiian hotspots: enhanced megafaunal abundance and diversity in submarine canyons on the oceanic islands of Hawaii     

Eric W. Vetter  Craig R. Smith  & Fabio C. De Leo 《Marine Ecology》2010,31(1):183-199

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Mediterranean shelf-edge muddy contourites: examples from the Gela and South Adriatic basins   总被引：2，自引：1，他引：1  

Giuseppe?VerdicchioEmail author  Fabio?Trincardi 《Geo-Marine Letters》2008,28(3):137-151

We present new evidence of shallow-water muddy contourite drifts at two distinct locations in the central Mediterranean characterized by a relatively deep shelf edge (between 170 and 300 m below sea level): the south-eastern Adriatic margin and the north-western Sicily Channel. The growth of these shelf-edge contourite drifts is ascribed to the long-term impact of the Mediterranean themohaline circulation. The Levantine Intermediate Water flows continuously, with annual or inter-annual variations, and affects the shelf edge and the upper slope in both study areas. In addition, the SW Adriatic margin is impinged by the seasonally modulated off-shelf cascading of North Adriatic Dense Water. This water mass has formed ever since the large Adriatic continental shelf was drowned by the post-glacial sea-level rise. It energetically sweeps the entire slope from the shelf edge to the deep basin. These bottom currents flow parallel or oblique to the depth contours, and are laterally constricted along markedly erosional moats aligned parallel to the shelf edge where they increase in flow velocity. The internal geometry and growth patterns of the shelf-edge contourites reflect changes in oceanographic setting affecting the whole Mediterranean Sea. In particular, seismic correlation with published sediment cores documents that these deposits are actively growing and migrating during the present interglacial, implying an enhancement in bottom-water formation during intervals of relative sea-level rise and highstand. Regardless of the specific mechanisms of formation, sediment drifts in both study areas have been affected by widespread thin-skinned mass-wasting events during post-glacial times. Repeated mass-transport processes have affected in particular the downslope flank of the shelf-edge contourite drifts, indicating that these muddy deposits are prone to failure during, or soon after, their deposition.  相似文献   

Bounds on the eigenvalues of the planetary-scale baroclinic instability problem     

Fabio Cavallini  Fulvio Crisciani  Renzo Mosetti 《Dynamics of Atmospheres and Oceans》1988,12(1)

In the framework of the linear baroclinic instability problem for planetary geostrophic flows, bounds on the related complex eigenvalues are deduced. The main feature of this result is the independence of these bounds from the latitude and the density stratification, so that it generalizes the results of previous work on the subject.  相似文献   

DmpIRFs and DmpST:DAMPE instrument response functions and science tools for gamma-ray data analysis     

Kai-Kai Duan  Wei Jiang  Yun-Feng Liang  Zhao-Qiang Shen  Zun-Lei Xu  Yi-Zhong Fan  Fabio Gargano  Simone Garrappa  Dong-Ya Guo  Shi-Jun Lei  Xiang Li  Mario Nicola Mazziotta  Maria Fernanda Munoz Salinas  Meng Su  Valerio Vagelli  Qiang Yuan  Chuan Yue  Stephan Zimmer 《天文和天体物理学研究(英文版)》2019,(9)

Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response functions for DAMPE(DmpIRFs) including the effective area, point-spread function and energy dispersion, which are crucial for gamma-ray data analysis based on statistics from simulation data. A dedicated software named DmpST is developed to facilitate the scientific analyses of DAMPE gamma-ray data. Considering the limited number of photons and angular resolution of DAMPE, the maximum likelihood method is adopted in DmpST to better disentangle different source components. The basic mathematics and framework regarding this software are also introduced in this paper.  相似文献   

Decoupling the effects of deforestation and climate variability in the Tapajós river basin in the Brazilian Amazon          下载免费PDF全文

Mauricio E. Arias  Eunjee Lee  Fabio Farinosi  Fabio F. Pereira  Paul R. Moorcroft 《水文研究》2018,32(11):1648-1663

Tropical river basins are experiencing major hydrological alterations as a result of climate variability and deforestation. These drivers of flow changes are often difficult to isolate in large basins based on either observations or experiments; however, combining these methods with numerical models can help identify the contribution of climate and deforestation to hydrological alterations. This paper presents a study carried out in the Tapaj?s River (Brazil), a 477,000 km² basin in South‐eastern Amazonia, in which we analysed the role of annual land cover change on daily river flows. Analysis of observed spatial and temporal trends in rainfall, forest cover, and river flow metrics for 1976 to 2008 indicates a significant shortening of the wet season and reduction in river flows through most of the basin despite no significant trend in annual precipitation. Coincident with seasonal trends over the past 4 decades, over 35% of the original forest (140,000 out of 400,000 km²) was cleared. In order to determine the effects of land clearing and rainfall variability to trends in river flows, we conducted hindcast simulations with ED2 + R, a terrestrial biosphere model incorporating fine scale ecosystem heterogeneity arising from annual land‐use change and linked to a flow routing scheme. The simulations indicated basin‐wide increases in dry season flows caused by land cover transitions beginning in the early 1990s when forest cover dropped to 80% of its original extent. Simulations of historical potential vegetation in the absence of land cover transitions indicate that reduction in rainfall during the dry season (mean of ?9 mm per month) would have had an opposite and larger magnitude effect than deforestation (maximum of +4 mm/month), leading to the overall net negative trend in river flows. In light of the expected increase in future climate variability and water infrastructure development in the Amazon and other tropical basins, this study presents an approach for analysing how multiple drivers of change are altering regional hydrology and water resources management.  相似文献   

Discovery of cryptotephra at Middle–Upper Paleolithic sites Arma Veirana and Riparo Bombrini,Italy: a new link for broader geographic correlations     

Jayde N. Hirniak  Eugene I. Smith  Racheal Johnsen  Minghua Ren  Jamie Hodgkins  Caley Orr  Fabio Negrino  Julien Riel-Salvatore  Shelby Fitch  Christopher E. Miller  Andrea Zerboni  Guido S. Mariani  Jacob A. Harris  Claudine Gravel-Miguel  David Strait  Marco Peresani  Stefano Benazzi  Curtis W. Marean 《第四纪科学杂志》2020,35(1-2):199-212

Chemical characterization of cryptotephra is critical for temporally linking archaeological sites. Here, we describe cryptotephra investigations of two Middle–Upper Paleolithic sites from north-west Italy, Arma Veirana and Riparo Bombrini. Cryptotephra are present as small (<100 µm) rhyolitic glass shards at both sites, with geochemical signatures rare for volcanoes in the Mediterranean region. Two chemically distinct shard populations are present at Arma Veirana (P1 and P2). P1 is a high silica rhyolite (>75 wt.%) with low FeO (<1 wt.%) and a K₂O/Na₂O > 1 and P2 is also a high silica rhyolite (>75 wt.%) but with higher FeO (2.33–2.65 wt.%). Shards at Riparo Bombrini (P3) are of the same composition as P1 shards at Arma Veirana, providing a distinct link between deposits at both sites. Geochemical characteristics suggest three possible sources for P1 and P3: eruptions from Lipari Island (56–37.7 ka) in Italy, the Acigöl volcanic field (200–20 ka) in Turkey and the Miocene Kirka-Phrigian caldera (18 Ma) in Turkey. Eruptions from Lipari Island are the most likely source for P1,3 cryptotephra. This study highlights how cryptotephra can benefit archaeology, by providing a direct link between Arma Veirana and Riparo Bombrini as well as other deposits throughout the Mediterranean.  相似文献   

意大利东北部晚三叠世一新翼龙     

Fabio M. DALLA VECCHIA 《地球学报》2010,31(Z1):17-17

To date, the middle-late Norian Dolomia di Forni Formation of the Friuli region of NE Italy has yielded ten pterosaur specimens. They include the holotypes of Preondactylus buffarinii Wild, 1984 and Carniadactylus rosenfeldi (Dalla Vecchia, 1995) and a specimen referred to Austriadactylus cristatus Dalla Vecchia, Wild, Hopf & Reitner, 2002.  相似文献   

Extended time weather forecasts contributes to agricultural productivity estimates     

Andrea de Oliveira Cardoso  Hilton Silveira Pinto  Ana Maria Heuminski de Ávila  Pedro Leite da Silva Dias  Fabio Ricardo Marin  Felipe Pilau 《Theoretical and Applied Climatology》2010,102(3-4):343-350

Weather conditions in critical periods of the vegetative crop development influence crop productivity, thus being a basic parameter for crop forecast. Reliable extended period weather forecasts may contribute to improve the estimation of agricultural productivity. The production of soybean plays an important role in the Brazilian economy, because this country is ranked among the largest producers of soybeans in the world. This culture can be significantly affected by water conditions, depending on the intensity of water deficit. This work explores the role of extended period weather forecasts for estimating soybean productivity in the southern part of Brazil, Passo Fundo, and Londrina (State of Rio Grande do Sul and Paraná, respectively) in the 2005/2006 harvest. The goal was to investigate the possible contribution of precipitation forecasts as a substitute for the use of climatological data on crop forecasts. The results suggest that the use of meteorological forecasts generate more reliable productivity estimates during the growth period than those generated only through climatological information.  相似文献   

The many manifestations of downsizing: hierarchical galaxy formation models confront observations     

Fabio Fontanot  Gabriella De Lucia  Pierluigi Monaco  Rachel S. Somerville  Paola Santini 《Monthly notices of the Royal Astronomical Society》2009,397(4):1776-1790

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Faint Lyman-break galaxies as a crucial test for galaxy formation models     

Barbara Lo Faro  Pierluigi Monaco  Eros Vanzella  Fabio Fontanot  Laura Silva  Stefano Cristiani 《Monthly notices of the Royal Astronomical Society》2009,399(2):827-841

It has recently been shown that galaxy formation models within the Λ cold dark matter cosmology predict that, compared to the observed population, small galaxies (with stellar masses  <10¹¹ M_⊙  ) form too early, are too passive since   z ∼ 3  and host too old stellar populations at   z = 0  . We then expect an overproduction of small galaxies at   z ≳ 4  that should be visible as an excess of faint Lyman-break galaxies. To check whether this excess is present, we use the morgana galaxy formation model and grasil spectrophotometric  +  radiative transfer code to generate mock catalogues of deep fields observed with Hubble Space Telescope Advanced Camera for Surveys. We add observational noise and the effect of Lyman α emission, and perform colour–colour selections to identify Lyman-break galaxies. The resulting mock candidates have plausible properties that closely resemble those of observed galaxies. We are able to reproduce the evolution of the bright tail of the luminosity function of Lyman-break galaxies (with a possible underestimate of the number of the brightest i -dropouts), but uncertainties and degeneracies in dust absorption parameters do not allow to give strong constraints to the model. Besides, our model shows a clear excess with respect to observations of faint Lyman-break galaxies, especially of   z ₈₅₀∼ 27 V   -dropouts at   z ∼ 5  . We quantify the properties of these 'excess' galaxies and discuss the implications: these galaxies are hosted in dark matter haloes with circular velocities in excess of 100 km s⁻¹, and their suppression may require a deep rethinking of stellar feedback processes taking place in galaxy formation.  相似文献