Time-dependent photoionization opacities in dense gamma-ray burst environments     

Davide Lazzati  Rosalba Perna  Gabriele Ghisellini 《Monthly notices of the Royal Astronomical Society》2001,325(4):L19-L23

The recent detection of a transient absorption feature in the X-ray prompt emission of GRB 990705 showed the importance of such observations in the understanding of gamma-ray bursts and their progenitors. We investigate the time dependence of photoionization edges during the prompt emission of bursts in different environments. We show that their variability can be used to infer the density and geometry of the surrounding medium, giving important clues to unveil the nature of the burst progenitor.  相似文献   

Modeling households’ decisions on reconstruction of houses damaged by earthquakes––Japanese case study     

H. Sakakibara  H. Murakami  S. Esaki  D. Mori  H. Nakata 《Natural Hazards》2008,44(2):293-303

In this study, households’ decisions on reconstruction of damaged houses were modeled, using questionnaire data in Japan. Characteristics of households’ decisions were investigated using parameter estimation results. The effects of subsidizing policy were evaluated as follows. First, subsidy for rebuilding may be effective for the households whose houses were heavily damaged. Second, there is a possibility that subsidy accelerated rebuilding of houses by the households having children. Third, subsidy for rebuilding may not be effective for elderly people’s households and households in depopulated areas.  相似文献   

Uncertainties in projected runoff over the conterminous United States     

Ignazio Giuntoli  Gabriele Villarini  Christel Prudhomme  David M. Hannah 《Climatic change》2018,150(3-4):149-162

Projections of runoff from global multi-model ensembles provide a valuable basis for the estimation of future hydrological extremes. However, projections suffer from uncertainty that originates from different error sources along the modeling chain. Hydrological impact studies have generally partitioned these error sources into global impact and global climate model (GIM and GCM, respectively) uncertainties, neglecting other sources, including scenarios and internal variability. Using a set of GIMs driven by GCMs under different representative concentration pathways (RCPs), this study aims to partition the uncertainty of future flows coming from GIMs, GCMs, RCPs, and internal variability over the CONterminous United States (CONUS). We focus on annual maximum, median, and minimum runoff, analyzed decadally over the twenty-first century. Results indicate that GCMs and GIMs are responsible for the largest fraction of uncertainty over most of the study area, followed by internal variability and to a smaller extent RCPs. To investigate the influence of the ensemble setup on uncertainty, in addition to the full ensemble, three ensemble configurations are studied using fewer GIMs (excluding least credible GIMs in runoff representation and GIMs accounting for vegetation and CO₂ dynamics), and excluding intermediate RCPs. Overall, the use of fewer GIMs has a minor impact on uncertainty for low and medium flows, but a substantial impact for high flows. Regardless of the number of pathways considered, RCPs always play a very small role, suggesting that improvement of GCMs and GIMs and more informed ensemble selections can yield a reduction of projected uncertainties.  相似文献   

Analysis of changes in the magnitude,frequency, and seasonality of heavy precipitation over the contiguous USA     

Mallakpour  Iman  Villarini  Gabriele 《Theoretical and Applied Climatology》2017,130(1-2):345-363

Theoretical and Applied Climatology - Gridded daily precipitation observations over the contiguous USA are used to investigate the past observed changes in the frequency and magnitude of heavy...  相似文献   

Mature vs. Active Deep-Seated Landslides: A Comparison Through Two Case Histories in the Alps     

Luca Delle Piane  Paolo Perello  Alessandro Baietto  Alessandra Giorza  Alessia Musso  Piercarlo Gabriele  Ira Baster 《Rock Mechanics and Rock Engineering》2016,49(6):2189-2216

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Interactions Between the Nighttime Valley-Wind System and a Developing Cold-Air Pool     

Gabriele Arduini  Chantal Staquet  Charles Chemel 《Boundary-Layer Meteorology》2016,161(1):49-72

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Baryon loading and the Weibel instability in gamma-ray bursts     

M. Fiore  L. O. Silva  C. Ren  M. A. Tzoufras  W. B. Mori 《Monthly notices of the Royal Astronomical Society》2006,372(4):1851-1855

The dynamics of two counter-streaming electron–positron–ion unmagnetized plasma shells with zero net charge is analysed in the context of magnetic field generation in gamma-ray burst internal shocks due to the Weibel instability. The effects of large thermal motion of plasma particles, arbitrary mixture of plasma species and space charge effects are taken into account. We show that, although thermal effects slow down the instability, baryon loading leads to a non-negligible growth rate even for large temperatures and different shell velocities, thus guaranteeing the robustness and the occurrence of the Weibel instability for a wide range of scenarios.  相似文献   

Iron oxidation state in the Fe‐rich layer and silica matrix of Libyan Desert Glass: A high‐resolution XANES study     

Gabriele Giuli  Eleonora Paris  Giovanni Pratesi  Christian Koeberl  Curzio Cipriani 《Meteoritics & planetary science》2003,38(8):1181-1186

Abstract— Libyan Desert Glass (LDG) is an enigmatic type of glass that occurs in western Egypt in the Libyan Desert. Fairly convincing evidence exists to show that it formed by impact, although the source crater is currently unknown. Some rare samples present dark‐colored streaks with variable amounts of Fe, and they are supposed to contain a meteoritic component. We have studied the iron local environment in an LDG sample by means of Fe K‐edge highresolution X‐ray absorption near edge structure (XANES) spectroscopy to obtain quantitative data on the Fe oxidation state and coordination number in both the Fe‐poor matrix and Fe‐rich layers. The pre‐edge peak of the high‐resolution XANES spectra of the sample studied displays small but reproducible variations between Fe‐poor matrix and Fe‐rich layers, which is indicative of significant changes in the Fe oxidation state and coordination number. Comparison with previously obtained data for a very low‐Fe sample shows that, while iron is virtually all trivalent and in tetrahedral coordination (^[4]Fe³⁺) in the low‐Fe sample, the sample containing the Fe‐rich layers display a mixture of tetra‐coordinated trivalent iron (^[4]Fe³⁺) and penta‐coordinated divalent iron (^[5]Fe²⁺), with the Fe in the Fe‐rich layer being more reduced than the matrix. From these data, we conclude the following: a) the significant differences in the Fe oxidation state between LDG and tektites, together with the wide intra‐sample variations in the Fe‐oxidation state, confirm that LDG is an impact glass and not a tektite‐like glass; b) the higher Fe content, coupled with the more reduced state of the Fe, in the Fe‐rich layers suggests that some or most of the Fe in these layers may be directly derived from the meteoritic projectile and that it is not of terrestrial origin.  相似文献   

Topography and Geoid Undulations Caused By Small-Scale Convection Beneath Continental Lithosphere of Variable Elastic Thickness   总被引：1，自引：0，他引：1  

Gabriele Marquart  Harro Schmeling 《Geophysical Journal International》1989,97(3):511-527

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3.3 Millimeter limb brightening measurements during the 30 June 1973 total solar eclipse     

F. I. Shimabukuro  W. J. Wilson  T. T. Mori  P. L. Smith 《Solar physics》1975,40(2):359-370

Solar limb brightening measurements at a wavelength of 3.3 mm were made during the 30 June 1973 total solar eclipse from a site at Lake Rudolf, Kenya. The results show that at this wavelength there is a limb brightening of about 20%, occurring within one half arc min of the limb.  相似文献