Global instability in the Ghil–Sellers model     

Tamás Bódai  Valerio Lucarini  Frank Lunkeit  Robert Boschi 《Climate Dynamics》2015,44(11-12):3361-3381

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Self-standing bent silicon crystals for very high efficiency Laue lens     

Valerio Bellucci  Riccardo Camattari  Vincenzo Guidi  Ilaria Neri  Nicolas Barri��re 《Experimental Astronomy》2011,31(1):45-58

Silicon mono-crystals have been bent thanks to a series of parallel superficial indentations on one of the largest faces of the crystals. This technique relies on irreversible compression of the crystal beneath and beside the indentations. This latter causes deformation with no need for external device, resulting in a uniform self-standing curvature within the crystal. Indented Si crystals have been characterized at European Synchrotron Radiation Facility using a monochromatic beam ranging from 150 to 700 keV. Crystals exhibited very high diffraction efficiency over a broad range of energy, peaking 95% at 150 keV. Measured angular spread of the diffracted beam was always very close to the morphological curvature of the sample under investigation, proving that the energy passband of bent crystals can be controlled by simply imparting a selected curvature to the sample. The method of superficial indentations was found to offer high reproducibility and easy control of diffraction properties of the crystals. Moreover the method is cheap and simple, being based on mass production tools. A Laue lens made of crystals bent by superficial indentations can provide high-efficiency concentration of hard x-ray photons, leading significant improvement in many astrophysical applications.  相似文献   

Raman study of MgCO3–FeCO3 carbonate solid solution at high pressures up to 55 GPa     

Anna Spivak  Natalia Solopova  Valerio Cerantola  Elena Bykova  Egor Zakharchenko  Leonid Dubrovinsky  Yuriy Litvin 《Physics and Chemistry of Minerals》2014,41(8):633-638

Magnesite, siderite and ferromagnesites Mg_1?x Fe _x CO₃ (x = 0.05, 0.09, 0.2, 0.4) were characterized using in situ Raman spectroscopy at high pressures up to 55 GPa. For the Mg–Fe-carbonates, the Raman peak positions of six modes (T, L, ν₄, ν₁, ν₃ and 2ν₂) in the dependence of iron content in the carbonates at ambient conditions are presented. High-pressure Raman spectroscopy shows that siderite undergoes a spin transition at ~40 GPa. The examination of the solid solutions with compositions Mg_0.6Fe_0.4CO₃, Mg_0.8Fe_0.2CO₃, Mg_0.91Fe_0.09CO₃ and Mg_0.95Fe_0.05CO₃ indicates that with increase in the amount of the Fe spin transition pressure increases up to ~45 GPa.  相似文献   

Can starvation influence cellular and biochemical parameters in the crab Carcinus aestuarii?     

Matozzo V  Gallo C  Marin MG 《Marine environmental research》2011,71(3):207-212

Crustacea experience periods of starvation during moulting or when limited food availability occurs. The effects of starvation on Crustacea physiological responses have been demonstrated, whereas the effects of starvation on Crustacea immune parameters remain to be more fully studied. In the present study the effects of starvation on immune parameters and antioxidant enzyme activities of the crab Carcinus aestuarii were evaluated for the first time. Treated crabs were starved for 7 days, whereas control crabs were fed daily with mussels. Total haemocyte count (THC), haemocyte diameter and volume, haemocyte proliferation, cell-free haemolymph (CFH) glucose and total protein levels, and phenoloxidase (PO) activity in both haemocyte lysate (HL) and CFH were measured in crabs. In addition, superoxide dismutase (SOD) and catalase (CAT) activities were evaluated in both gills and digestive gland from crabs, in order to evaluate whether starvation induced oxidative stress in C. aestuarii. THC increased significantly in starved crabs, with respect to controls, whereas no significant variations were observed in haemocyte diameter, volume and proliferation. In CFH of starved animals glucose concentration significantly increased, whereas total protein concentration significantly reduced. A significantly higher PO activity was recorded in HL from starved crabs, than in control crabs. Conversely, PO activity did not vary significantly in CFH. Starvation did not cause significant alterations in antioxidant enzyme activities in both gills and digestive gland. Results obtained demonstrated that starvation influenced crab immune parameters, but did not induce oxidative stress. Results also indicated that C. aestuarii can modulate its cellular and biochemical parameters in order to cope with starvation.  相似文献   

Exposure of the clam Tapes philippinarum to 4-nonylphenol: changes in anti-oxidant enzyme activities and re-burrowing capability     

Matozzo V  Ballarin L  Marin MG 《Marine pollution bulletin》2004,48(5-6):563-571

The effects of 4-nonylphenol on anti-oxidant enzyme (superoxide dismutase and catalase) activity in both gills and digestive gland and re-burrowing capability of the clam Tapes philippinarum were investigated after 7 days' exposure to various sublethal concentrations of nonylphenol (NP). NP caused a significant decrease in superoxide dismutase activity in both tissues from the lowest concentration tested, whereas no significant alteration with respect to controls was observed in catalase activity. NP effects on re-burrowing of clams were evaluated in two experiments. In the first, clams exposed to the highest NP concentrations showed a marked delay in re-burrowing 48 h after the end of exposure. Modifications in normal burrowing behaviour were also observed, suggesting that NP acts via narcosis and/or neurotoxic mechanisms. In the second experiment, the elapsed time for 50% of the exposed clams to re-burrow into the sediment (RT(50)) was also calculated in a 24-h re-burrowing response test. At the highest NP concentrations, it was not possible to estimate RT(50) values, as the percentage of clams showing complete burial was less than 50%. The present study demonstrates that NP causes oxidative stress by inhibiting superoxide dismutase activity and greatly affects the re-burrowing capability of T. philippinarum, even at environmentally realistic concentrations.  相似文献   

Erratum to: Large-scale mitochondrial phylogeography in the halophilic fairy shrimp Phallocryptus spinosa (Milne-Edwards, 1840) (Branchiopoda: Anostraca)     

Valerio Ketmaier  Daniela Pirollo  Elvira De Matthaeis  Ralph Tiedemann  Graziella Mura 《Aquatic Sciences - Research Across Boundaries》2013,75(2):333-334

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Sensitivity of the multiannual thermal dynamics of a deep pre‐alpine lake to climatic change          下载免费PDF全文

Giulia Valerio  Marco Pilotti  Stefano Barontini  Barbara Leoni 《水文研究》2015,29(5):767-779

The study of the multiannual thermal dynamics of Lake Iseo, a deep lake in the Italian pre‐alpine area, is presented. Interflow was found to be the dominant river entrance mode, suggesting future susceptibility of the lake thermal structure to the overall effects of climate change expected in the upstream alpine watershed. A lake model employed the results of a long‐term hydrologic model to simulate the effects of a climate change scenario on the lake's thermal evolution for the period 2012–2050. The model predicts an overall average increase in the lake water temperature of 0.012 °C/year and a reinforced Schmidt thermal stability of the water column in the winter up to 800 J/m². Both these effects may further hinder the deep circulation process, which is vital for the oxygenation of deep water. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Miocene sedimentation,volcanism and deformation in the Eastern Cordillera (24°30′ S,NW Argentina): tracking the evolution of the foreland basin of the Central Andes     

Luigina Vezzoli  Valerio Acocella  Ricardo Omarini  Roberto Mazzuoli 《Basin Research》2012,24(6):637-663

Understanding the relationships between sedimentation, tectonics and magmatism is crucial to defining the evolution of orogens and convergent plate boundaries. Here, we consider the lithostratigraphy, clastic provenance, syndepositional deformation and volcanism of the Almagro‐El Toro basin of NW Argentina (24°30′ S, 65°50′ W), which experienced eruptive and depositional episodes between 14.3 and 6.4 Ma. Our aims were to elucidate the spatial and temporal record of the onset and style of the shortening and exhumation of the Eastern Cordillera in the frame of the Miocene evolution of the Central Andes foreland basin. The volcano‐sedimentary sequence of the Almagro‐El Toro basin consists of lower red floodplain sandstones and siltstones, medial non‐volcanogenic conglomerates with localised volcanic centres and upper volcanogenic coarse conglomerates and breccia. Coarse, gravity flow‐dominated (debris‐flow and sheet‐flow) alluvial fan systems developed proximal to the source area in the upper and medial sequence. Growing frontal and intrabasinal structures suggest that the Almagro‐El Toro portion of the foreland basin accumulated on top of the eastward‐propagating active thrust front of the Eastern Cordillera. Synorogenic deposits indicate that the shortening of the foreland deposits was occurring by 11.1 Ma, but conglomerates derived from the erosion of western sources suggest that the uplift and erosion of this portion of the Eastern Cordillera has occurred since ca.12.5 Ma. An unroofing reconstruction suggests that 6.5 km of rocks were exhumed. A tectono‐sedimentary model of an episodically evolving thick‐skinned foreland basin is proposed. In this frame, the NW‐trending, transtensive Calama–Olacapato–El Toro (COT) structures interacted with the orogen, influencing the deposition and deformation of synorogenic conglomerates, the location of volcanic centres and the differential tilt and exhumation of the foreland.  相似文献   

A Grid platform for the European Civil Protection e-Infrastructure: the Forest Fires use scenario     

Paolo Mazzetti  Stefano Nativi  Valerio Angelini  Marco Verlato  Paolo Fiorucci 《Earth Science Informatics》2009,2(1-2):53-62

During the full cycle of the emergency management, Civil Protection operative procedures involve many actors belonging to several institutions playing different roles. In this context the sharing of information is a vital requirement to make correct and effective decisions. Therefore a European-wide technological infrastructure providing a distributed and coordinated access to different kinds of resources (data, information, services, expertise, etc.) could enhance existing Civil Protection applications and even enable new ones. In the recent years Grid technologies have reached a mature state providing a platform for secure and coordinated resource sharing between the participants in the so-called Virtual Organizations. Moreover the Earth and Space Sciences Informatics provide the conceptual tools for modelling the geospatial information shared in Civil Protection applications during its entire life cycle. Therefore a European Civil Protection e-infrastructure could be based on a Grid platform enhanced with Earth Sciences specific services. However Civil Protection applications stress the requirements of Earth Sciences research applications, for example in terms of real-time support. Therefore a set of high-level services specifically tailored for such applications must be built on top of the Grid platform. As a result of a requirement analysis, the FP6 project CYCLOPS has proposed an architectural framework for the future European Civil Protection e-Infrastructure. In this architecture a layer of high-level services tailored to Civil Protection applications is built on top of the EGEE Grid middleware. This architectural approach has been tested implementing a prototype of a grid-enabled RISICO, the application for wild fire risk assessment used by the Italian Civil Protection.  相似文献   

Intercomparison of the northern hemisphere winter mid-latitude atmospheric variability of the IPCC models     

Valerio Lucarini  Sandro Calmanti  Alessandro Dell’Aquila  Paolo M. Ruti  Antonio Speranza 《Climate Dynamics》2007,28(7-8):829-848

We compare, for the overlapping time frame 1962–2000, the estimate of the northern hemisphere mid-latitude winter atmospheric variability within the available 20th century simulations of 19 global climate models included in the Intergovernmental Panel on Climate Change—4th Assessment Report with the NCEP-NCAR and ECMWF reanalyses. We compute the Hayashi spectra of the 500 hPa geopotential height fields and introduce an ad hoc integral measure of the variability observed in the Northern Hemisphere on different spectral sub-domains. The total wave variability is taken as a global scalar metric describing the overall performance of each model, while the total variability pertaining to the eastward propagating baroclinic waves and to the planetary waves are taken as scalar metrics describing the performance of each model phenomenologically in connection with the corresponding specific physical process. Only two very high-resolution global climate models have a good agreement with reanalyses for both the global and the process-oriented metrics. Large biases, in several cases larger than 20%, are found in all the considered metrics between the wave climatologies of most IPCC models and the reanalyses, while the span of the climatologies of the various models is, in all cases, around 50%. In particular, the travelling baroclinic waves are typically overestimated by the climate models, while the planetary waves are usually underestimated, in agreement with what found is past analyses performed on global weather forecasting models. When comparing the results of similar models, it is apparent that in some cases the vertical resolution of the model atmosphere, the adopted ocean model, and the advection schemes seem to be critical in the bulk of the atmospheric variability. The models ensemble obtained by arithmetic averaging of the results of all models is biased with respect to the reanalyses but is comparable to the best five models. Nevertheless, the models results do not cluster around their ensemble mean. This study suggests caveats with respect to the ability of most of the presently available climate models in representing the statistical properties of the global scale atmospheric dynamics of the present climate and, a fortiori, in the perspective of modeling climate change.  相似文献