On the central configurations of the planar 1 + 3 body problem     

Montserrat Corbera  Josep Maria Cors  Jaume Llibre 《Celestial Mechanics and Dynamical Astronomy》2011,109(1):27-43

We consider the Newtonian four-body problem in the plane with a dominat mass M. We study the planar central configurations of this problem when the remaining masses are infinitesimal. We obtain two different classes of central configurations depending on the mutual distances between the infinitesimal masses. Both classes exhibit symmetric and non-symmetric configurations. And when two infinitesimal masses are equal, with the help of extended precision arithmetics, we provide evidence that the number of central configurations varies from five to seven.  相似文献   

Structural investigations of the two polymorphs of synthetic Fe-cordierite and Raman spectroscopy of hexagonal Fe-cordierite     

Udo Haefeker  Reinhard Kaindl  Peter Tropper  Hannes Krüger  Volker Kahlenberg  Maria Orlova 《Mineralogy and Petrology》2014,108(4):469-478

The crystal structures of synthetic hexagonal and orthorhombic Fe-cordierite polymorphs with the space groups P6/mcc and Cccm were refined from single-crystal X-ray diffraction data to R _{1, hex}?=?3.14 % and R _{1, ortho}?=?4.48 %. The substitution of the larger Fe²⁺ for Mg leads to multiple structural changes and an increase of the unit cell volumes, with a, c (hex)?=?9.8801(16) Å, 9.2852(5) Å and a, b, c (ortho)?=?17.2306(2) Å, 9.8239(1) Å, 9.2892(1) Å in the end-members. Furthermore Fe incorporation results in an increase of the volumes of the octahedra, although the diameters of the octahedra in direction of the c-axis decrease in both polymorphs. X-ray powder diffraction analysis indicates a high degree of Al/Si ordering in the orthorhombic polymorph, the Miyashiro distortion index is ~0.24. Estimations of site occupancies based on the determined tetrahedral volumes result in the following values for hexagonal Fe-cordierite: ~73 % Al for T₁ and ~28 % Al for T₂. For the first time Raman spectroscopy was performed on the hexagonal Fe-cordierite polymorph. In the hexagonal Fe-cordierite polymorph most Raman peaks are shifted towards lower wavenumbers when compared with the Mg-end-member.  相似文献   

Relationship between hydrogeological parameters for data-scarce regions: the case of the Araripe sedimentary basin, Brazil   总被引：1，自引：0，他引：1  

Sávio de Brito Fontenele  Luiz Alberto Ribeiro Mendonça  José Carlos de Araújo  Maria Marlúcia Freitas Santiago  José Yarley de Brito Gonçalves 《Environmental Earth Sciences》2014,71(2):885-894

This paper applies and validates a method for generating spatially distributed hydraulic conductivity (k) based on the specific capacity (Q _s) for data-scarce regions. This method has been applied to the Araripe sedimentary basin, Brazil, and consists of four steps: (1) selection of (32) wells for which both k and Q _s data are available; (2) estimation of k as a function of Q _s for the (128) wells for which only specific capacity data are available; (3) spatial distribution of k using the kriging geostatistical tool; (4) validation of the method, using (17) representative wells with k measured data. The equation relating k and Q _s showed a statistically significant linear relationship (R = 0.93), from which a database has been generated using kriging with the spherical model. The results showed a calibration coefficient of Nash and Sutcliffe (NS) of 0.54 and moderate spatial dependence ratio of 69 %. The validation process provided only a moderate efficiency (NS = 0.22), possibly due to the geological complexity of the focus system. Despite its limitations, the method indicates the possibility of application of ordinary kriging to generate reliable data from auxiliary variables, especially for the water management of data-scarce areas.  相似文献   

Characterisation of rapid infiltration flows and vulnerability in a karst aquifer using a decomposed fluorescence signal of dissolved organic matter     

Marine Quiers  Christelle Batiot-Guilhe  Cristina C. Bicalho  Yves Perrette  Jean-Luc Seidel  Sandra Van Exter 《Environmental Earth Sciences》2014,71(2):553-561

The fluorescent properties of dissolved organic matter (DOM) have been used as natural tracers in various water systems. However, only few studies have focused on groundwater systems, specifically, on karst systems. The aim of this study was to develop the use of the DOM fluorescence signal as a natural tracer, considering the multiple compartments of a karst system. This method was applied to the Lez hydrosystem, which supplies the city of Montpellier with drinking water. The hydrodynamics and hydrochemistry of the spring were monitored beginning March 2006. The DOM fluorescence was measured by the excitation–emission matrix spectroscopy technique. The analysis of the total fluorescence signal confirms the efficiency of this tool to trace rapid infiltration flows. Moreover, the decomposition of the signal into different fluorophores complements the information provided by the total signal. Indeed, the fluorescence emitted by the humic compounds seems to be the ideal tool for identifying rapid infiltration flows. Nevertheless, the fluorescence of protein-like compounds is better correlated with the inflow of faecal bacteria at the outlet. This decomposition of the fluorescence signal is an interesting way to provide information on both the rapid infiltration flow as well as the vulnerability of the karst aquifers.  相似文献   

Seasonal and spatial variations of water quality,substrate and aquatic macrophytes based on side scan sonar,in an eastern Mediterranean lagoon (Kaiafas,Ionian Sea)     

Chrysoula Christia  Eva Papastergiadou  George Papatheodorou  Maria Geraga  Emmanouil Papadakis 《Environmental Earth Sciences》2014,71(8):3543-3558

Temporal and spatial variations of environmental and water quality parameters and their relations with macrobenthic flora were investigated in an eastern Mediterranean lagoon. Kaiafas is a mesohaline lagoon, which is influenced by point and diffused sources from the adjacent agricultural land and the nearby city. Water samples were analyzed for physicochemical parameters, microbial load and primary production, on a seasonal and spatial scale, while heavy metal concentrations were measured into two different sediment cores. An overall analysis of seasonal dynamics of water parameters and Chl-a based on trophic index TSI pointed out the lagoon as eutrophic. According to water quality parameters the lagoon was separated into two parts. The southern sector of the lagoon which was more affected by human activities showed higher nutrients, Chl-a, heavy metals and total Coliforms concentrations. Sediment texture and distribution of macrophytes were detected through the acoustic side scan sonar method, which proved to be a promising tool for defining and monitoring vegetation coverage of shallow lagoons. A number of distinct echo types and three different sediment types were revealed on the basis of the backscatter level and the variability of low and high backscatter areas. Furthermore, the extension and the coverage of Potamogeton pectinatus and Chara hispida f. corfuensis were successively depicted by combining the data of SSS and ground truthing samples. Meadows of P. pectinatus were established to the lagoon limits where high turbidity and silty substrate occurred, while C. hispida f. corfuensis was limited in deep and high transparent waters with sandy substrate.  相似文献   

Geo-portal as a planning instrument: supporting decision making and fostering market potential of Energy efficiency in buildings     

Branka Cuca  Raffaella Brumana  Daniela Oreni  Giuliana Iannaccone  Marta Maria Sesana 《Central European Journal of Geosciences》2014,6(1):121-130

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The tropical storm Noel and its effects on the territory of the Dominican Republic     

Michela Izzo  Pietro Patrizio Ciro Aucelli  Yudith Javier  Caridad Pérez  Carmen Maria Rosskopf 《Natural Hazards》2010,53(1):139-158

In the period between the end of October and the beginning of November 2007, the Dominican Republic was hit by the tropical storm Noel, then turned into hurricane in its movement toward the Californian coasts. The passage of Noel was accompanied by huge precipitation especially in the south-western part of the country. In some areas, the rainfall registered in 6 days exceeded 700 mm, i.e., more than two-thirds of the mean annual precipitation. The return periods calculated for this rainfall event vary greatly from region to region: while they locally reach 200 years, such as in San José de Ocoa (50 km west of Santo Domingo), in other areas, as for instance in the territory of the capital Santo Domingo, return periods do not exceed 20 years. The tropical storm caused huge damage both in terms of human victims and economic losses, related to diffused inundations and landslide phenomena, which may be attributed only partially to the exceptionality of the event. As a matter of fact, in many regions, the inadequate answer of the territory—widely characterized by serious problems of land degradation and an almost complete lack of territorial planning—appears to be the major responsible for the occurred negative effects. The impact assessment, based on the calculation of an Impact Index, confirms this statement.  相似文献   

It starts at home? Climate policies targeting household consumption and behavioral decisions are key to low-carbon futures     

Ghislain Dubois  Benjamin Sovacool  Carlo Aall  Maria Nilsson  Carine Barbier  Alina Herrmann  Sébastien Bruyère  Camilla Andersson  Bore Skold  Franck Nadaud  Florian Dorner  Karen Richardsen Moberg  Jean Paul Ceron  Helen Fischer  Dorothee Amelung  Marta Baltruszewicz  Jeremy Fischer  Françoise Benevise  Valérie R. Louis  Rainer Sauerborn 《Chemie der Erde / Geochemistry》2010

Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy.  相似文献   

Could the Twin Towers collapse teach the interaction of dilute pyroclastic density currents with buildings?     

Domenico Maria Doronzo 《Natural Hazards》2010,55(2):177-179

Particle-laden turbulent flows, called dilute pyroclastic density currents, can be generated during explosive volcanic eruptions. They are the most hazardous events of interaction with buildings and human environments in volcanic areas. A qualitative comparison with the dusty turbulent shear currents generated after the Twin Towers collapse on September 11, 2001 shows that turbulent, multiphase flow-building interaction causes flow separation and recirculation around the buildings. This simple idea could be applied to dilute pyroclastic density currents, and improved in future by adhoc numerical simulations of flow-building interaction.  相似文献   

Low VS crustal zones in the Campanian Plain (Southern Italy)     

Concettina Nunziata  Maria Rosaria Costanzo 《Mineralogy and Petrology》2010,100(3-4):215-225

Shear wave velocities of the lithospheric structure to 73 km depth have been defined along three profiles crossing the Campanian Plain (Southern Italy) from the simultaneous non linear inversion of the local and regional dispersion data. The former consist of group velocity dispersion data obtained from some seismic events which occurred at the borders of the Campanian Plain and recorded at Napoli, and the latter of group and phase dispersion data obtained in previous studies. The main features of the representative V_S models are a carbonate basement deepening to ～5 km in the central part of the Plain and a low velocity zone at a depth of ～15 km, rising to 7 km in the southern part, close to Somma-Vesuvio. The low velocity layer can be correlated with that found at ～10 km of depth below Campi Flegrei and the Neapolitan area, and at 5 km below the Somma-Vesuvio caldera area. Such regional velocity reduction can be associated to the presence of a zone with less than 5% partial melting that can be interpreted as magmatic reservoir of the Campanian volcanism.  相似文献