Occurrence of antifouling paint booster biocides in selected harbors and marinas inside the Gulf of Napoli: a preliminary survey     

Di Landa G  Ansanelli G  Ciccoli R  Cremisini C 《Marine pollution bulletin》2006,52(11):1541-1546

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Delayed action and uncertain stabilisation targets. How much will the delay cost?     

Valentina Bosetti  Carlo Carraro  Massimo Tavoni 《Climatic change》2009,96(3):299-312

Despite the growing concern about actual on-going climate change, there is little consensus on the scale and timing of actions needed to stabilise the concentrations of greenhouse gases. Many countries are unwilling to implement mitigation strategies, at least in the short term, and no agreement on an ambitious global stabilisation target has yet been reached. It is thus likely that international climate policies will be characterized by a high degree of uncertainty over the stringency of the climate objective, and that some countries might delay their participation to global action. What additional economic costs will this delay in the adoption of mitigation measures imply? What would the optimal short-term strategy be given the uncertainty surrounding the climate policy to come? Is there a hedging strategy that decision makers can adopt to cope with delayed action and uncertain targets? This paper addresses these questions by quantifying the economic implications of delaying mitigation action, and by computing the optimal abatement strategy in the presence of uncertainty about a global stabilisation target (which will be agreed upon in future climate negotiations). Results point to short-term inaction as the key determinant for the economic costs of ambitious climate policies. They also indicate that there is an effective hedging strategy that could minimise the cost of climate policy uncertainty over the global stabilisation target: a short-term moderate climate policy would be a good strategy to reduce the costs of delayed action and to cope with uncertainty about the outcome of future climate negotiations. By contrast, failing to curb emissions in the short term imposes rapidly increasing additional costs of compliance.  相似文献   

An Integrated Assessment of changes in the thermohaline circulation   总被引：1，自引：0，他引：1  

Till Kuhlbrodt  Stefan Rahmstorf  Kirsten Zickfeld  Frode Bendiksen Vikebø  Svein Sundby  Matthias Hofmann  Peter Michael Link  Alberte Bondeau  Wolfgang Cramer  Carlo Jaeger 《Climatic change》2009,96(4):489-537

This paper discusses the risks of a shutdown of the thermohaline circulation (THC) for the climate system, for ecosystems in and around the North Atlantic as well as for fisheries and agriculture by way of an Integrated Assessment. The climate model simulations are based on greenhouse gas scenarios for the 21st century and beyond. A shutdown of the THC, complete by 2150, is triggered if increased freshwater input from inland ice melt or enhanced runoff is assumed. The shutdown retards the greenhouse gas-induced atmospheric warming trend in the Northern Hemisphere, but does not lead to a persistent net cooling. Due to the simulated THC shutdown the sea level at the North Atlantic shores rises by up to 80 cm by 2150, in addition to the global sea level rise. This could potentially be a serious impact that requires expensive coastal protection measures. A reduction of marine net primary productivity is associated with the impacts of warming rather than a THC shutdown. Regional shifts in the currents in the Nordic Seas could strongly deteriorate survival chances for cod larvae and juveniles. This could lead to cod fisheries becoming unprofitable by the end of the 21st century. While regional socioeconomic impacts might be large, damages would be probably small in relation to the respective gross national products. Terrestrial ecosystem productivity is affected much more by the fertilization from the increasing CO₂ concentration than by a THC shutdown. In addition, the level of warming in the 22nd to 24th century favours crop production in northern Europe a lot, no matter whether the THC shuts down or not. CO₂ emissions corridors aimed at limiting the risk of a THC breakdown to 10% or less are narrow, requiring departure from business-as-usual in the next few decades. The uncertainty about THC risks is still high. This is seen in model analyses as well as in the experts’ views that were elicited. The overview of results presented here is the outcome of the Integrated Assessment project INTEGRATION.  相似文献   

The Ultraviolet sky surveys: filling the gap in our view of the Universe     

Luciana Bianchi 《Astrophysics and Space Science》2009,320(1-3):11-19

The GALEX mission is performing imaging and spectroscopic surveys of the sky at Ultraviolet wavelengths, and providing unprecedented sky maps in two UV bands, far-UV and near-UV, and catalogs of UV sources. I will describe the major surveys accomplished so far, and results in investigating the nature of the UV sources. The UV surveys, linked to a multi-wavelength archive, offer great sensitivity to detect and characterize several classes of astrophysical objects, such as low-redshift QSOs, star-forming galaxies, and white dwarfs (WD) in the Milky Way. Efforts towards obtaining a significant census of WDs from GALEX imaging data are described in particular. A dedicated, deep survey of nearby galaxies provides a snapshot of their recent star formation, shedding new light on the process of star formation and its modalities in different environments and conditions. Deep GALEX data revealed young stellar populations in extreme outskirts of spiral galaxies, previously thought to be stable against star formation given their low density. UV measurements for millions of nearby and distant galaxies map the history and probe the causes of star formation in the Universe over the redshift range z=0–2.  相似文献   

Crash-testing the cauldron code for joint lensing and dynamics analysis of early-type galaxies     

Matteo Barnabè  Carlo Nipoti  Léon V. E. Koopmans  Simona Vegetti  Luca Ciotti 《Monthly notices of the Royal Astronomical Society》2009,393(4):1114-1126

We apply the joint lensing and dynamics code for the analysis of early-type galaxies, 'Combined Algorithm for Unified Lensing and Dynamics ReconstructiON ( cauldron )', to a rotating N -body stellar system with dark matter halo which significantly violates the two major assumptions of the method, i.e. axial symmetry supported by a two-integral distribution function. The goal is to study how cauldron performs in an extreme case, and to determine which galaxy properties can still be robustly recovered. Three data sets, corresponding to orthogonal lines of sight, are generated from the N -body system and analysed with the identical procedure followed in the study of real lens galaxies, adopting an axisymmetric power-law total density distribution. We find that several global properties of the N -body system are recovered with remarkable accuracy, despite the fact that the adopted power-law model is too simple to account for the lack of symmetry of the true density distribution. In particular, the logarithmic slope of the total density distribution is robustly recovered to within less than 10 per cent (with the exception of the ill-constrained very inner regions), the inferred angle-averaged radial profile of the total mass closely follows the true distribution, and the dark matter fraction of the system (inside the effective radius) is correctly determined within ∼10 per cent of the total mass. Unless the line-of-sight direction is almost parallel to the total angular momentum vector of the system, reliably recovered quantities also include the angular momentum, the   V /σ  ratio and the anisotropy parameter δ. We conclude that the cauldron code can be safely and effectively applied to real early-type lens galaxies, also providing reliable information for the systems that depart significantly from the method's assumptions.  相似文献   

Stellar sources of dust in the high-redshift Universe     

Rosa Valiante  Raffaella Schneider  Simone Bianchi  Anja C. Andersen 《Monthly notices of the Royal Astronomical Society》2009,397(3):1661-1671

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Do high-velocity clouds form by thermal instability?     

James Binney  Carlo Nipoti  Filippo Fraternali 《Monthly notices of the Royal Astronomical Society》2009,397(4):1804-1815

We examine the proposal that the H  i 'high-velocity' clouds (HVCs) surrounding the Milky Way and other disc galaxies form by condensation of the hot galactic corona via thermal instability. Under the assumption that the galactic corona is well represented by a non-rotating, stratified atmosphere, we find that for this formation mechanism to work the corona must have an almost perfectly flat entropy profile. In all other cases, the growth of thermal perturbations is suppressed by a combination of buoyancy and thermal conduction. Even if the entropy profile were nearly flat, cold clouds with sizes smaller than  10 kpc  could form in the corona of the Milky Way only at radii larger than  100 kpc  , in contradiction with the determined distances of the largest HVC complexes. Clouds with sizes of a few kpc can form in the inner halo only in low-mass systems. We conclude that unless even slow rotation qualitatively changes the dynamics of a corona, thermal instability is unlikely to be a viable mechanism for formation of cold clouds around disc galaxies.  相似文献   

On the Transits of Solar System Objects in the Forthcoming Planck Mission: Data Flagging and Coeval Multi-Frequency Observations     

Michele Maris  Carlo Burigana 《Earth, Moon, and Planets》2009,105(2-4):81-88

In the context of current and future microwave surveys mainly dedicated to the accurate mapping of Cosmic Microwave Background (CMB), mm and sub-mm emissions from Solar System will represent a potential source of contamination as well as an opportunity for new Solar System studies. In particular, the forthcoming ESA Planck mission will be able to observe the point-like thermal emission from planets and some large asteroids as well as the diffused Zodiacal Light Emission (ZLE). After a brief introduction to the field, we focus on the identification of Solar System discrete objects in the Planck time ordered data.  相似文献   

Late Holocene glacial and periglacial evolution in the upper Orco Valley, northwestern Italian Alps     

Carlo Giraudi 《Quaternary Research》2009,71(1):1-8

The sediments present in some areas of the Orco Valley provide indications on climatic variations that occurred during the last 6000 years on the southern slopes of the Alps. In particular, distribution and ages of peat layers help define periods and extent of glacial fluctuation in the last 2200 years. Sampling of soils involved in periglacial processes provided a basis for development of a chronological framework of late Holocene environmental change. The data indicate a trend toward cooler climate in the second half of the Holocene. A strong relationship exists between phases of River Po flooding and expansion/retreat phases of the Swiss glaciers: major glacial advances were coeval with periods of intense flooding of the River Po, whereas the phases of glacial retreat coincided with periods of little flooding of the Po. Only in three cases do relationships between glacier activity and floods show weak correlations; two of the cases relate to the warmest periods in approximately the last 2200 years, while the third is the present period. Paleoclimatic evidence from the study region indicates the relatively warm Roman Period between about 2200 and 1900 cal yr BP appears to better represent modern conditions than does the Medieval Warm Period.  相似文献   

On the peculiar properties of the narrow-line quasar PG 1543+489     

Cristian Vignali  Enrico Piconcelli  Stefano Bianchi  Giovanni Miniutti 《Monthly notices of the Royal Astronomical Society》2008,388(2):761-769

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