Compact Groups of Galaxies: Evolution of the Stellar Population     

I. García De La Rosa  R. Coziol  R.R. De Carvalho  S. Zepf 《Astrophysics and Space Science》2001,276(2-4):717-723

We present a study focusing on the nature of compact groups (CGs) through the study of their elliptical (E) galaxies. Parameters describing the internal dynamics and the stellar populations of the galaxies are compared with their counterparts in other environments. Our sample has24 bright E galaxies located in the core of Hickson CGs and 11 bright ‘bona fide’ Es, located in the field or very loose groups. Their spectra were obtained with the 2.1 m Telescope at KPNO and have a 4.1 Å resolution over the wavelength range 3500–7000 Å. We have found that, from the dynamical point of view, E galaxies in CGs are essentially similar to those in dense clusters. Moreover, the stellar populations of Es in CGs seem to be older and less metal rich than those in the field, behaviour which has also been observed by Rose et al. (1994).  相似文献   

Sedimentary response of lake El Tobar,Spain, to climate: lake level changes after the Maunder Minimum          下载免费PDF全文

Charo López‐Blanco  Julian Andrews  Paul Dennis  María Rosa Miracle  Eduardo Vicente 《第四纪科学杂志》2016,31(8):905-918

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Fluctuation analysis of solar radio bursts associated with geoeffective X-class flares     

T.B. Veronese  R.R. Rosa  M.J.A. Bolzan  F.C. Rocha Fernandes  H.S. Sawant  M. Karlicky` 《Journal of Atmospheric and Solar》2011,73(11-12):1311-1316

High temporal resolution solar observations in the decimetric range (1–3 GHz) can provide additional information on solar active regions dynamics and thus contribute to better understanding of solar geoeffective events as flares and coronal mass ejections. The June 6, 2000 flares are a set of remarkable geoeffective eruptive phenomena observed as solar radio bursts (SRB) by means of the 3 GHz Ondrejov Observatory radiometer. We have selected and analyzed, applying detrended fluctuation analysis (DFA), three decimetric bursts associated to X1.1, X1.2 and X2.3 flare-classes, respectively. The association with geomagnetic activity is also reported. DFA method is performed in the framework of a radio burst automatic monitoring system. Our results may characterize the SRB evolution, computing the DFA scaling exponent, scanning the SRB time series by a short windowing before the extreme event. For the first time, the importance of DFA in the context of SRB monitoring analysis is presented.  相似文献   

A review of indicator minerals and sample processing methods for geochemical exploration     

Malcolm Gent  Mario MenendezJavier Toraño  Susana Torno 《Journal of Geochemical Exploration》2011

Geochemical exploration based on the analysis of indicator minerals (IMs) is becoming increasingly used as an effective method for mineral exploration for many types of mineral deposits. The types of IMs used or recommended for exploration for different types of deposits, their properties suitable for concentrating them, as well as those of other common minerals from which they must be separated are listed.  相似文献   

CFD simulation of blasting dust for the design of physical barriers     

Susana Torno  Javier Toraño  Mario Menéndez  Malcolm Gent 《Environmental Earth Sciences》2011,64(1):73-83

A computational fluid dynamics (CFD) model has been developed to simulate the dispersion of dust generated in blasting located in limestone quarries. This is a complex phenomenon that has been studied through the use of several digital video recordings of blasts and dust concentration field measurements by ‘light scattering’ dust collectors. In addition, the subsequent simulation of the dispersion of the dust cloud by means of multiphase CFD has also been studied. CFD calculations were carried out using software Ansys CFX 10.0, through transitory models with Lagrangian particle models crossing an Eulerian air continuous phase. This paper presents results obtained by model simulations where physical barriers are set close to the blasting, with the aim of decreasing the dust cloud dispersal and the associated environmental impact.  相似文献   

Assessing food web dynamics and relative importance of organic matter sources for fish species in two Portuguese estuaries: a stable isotope approach     

França S  Vasconcelos RP  Tanner S  Máguas C  Costa MJ  Cabral HN 《Marine environmental research》2011,72(4):204-215

Stable carbon and nitrogen isotopes (δ13C, δ1?N) were used to analyse food web dynamics of two of the main estuaries of the Portuguese coast: Tejo and Mira. The ultimate sources of organic matter supporting production of some of the most abundant and commercially important fish species were determined; and seasonal, inter- and intra- estuarine differences in the trophic relations among producers and consumers were identified. Stable isotope analysis was performed in different producers, primary consumers (main prey items for fish) and fish species (Solea solea, Solea senegalensis, Pomatoschistus microps, Dicentrarchus labrax, Liza ramada, Diplodus vulgaris and Atherina presbyter) of two areas in each estuary, in July and October 2009. Model calculations showed that the main prey for the fish species in the Tejo estuary used mostly salt marsh-derived organic matter as nutritional sources, with no marked differences between the sampled months. Trophic levels of fish species from the same estuary differed at multiple scales: inter-species, seasonally and spatially (both between and within estuaries). Significant differences in isotopic composition of fish species were more pronounced spatially (between the two sampled areas in the estuary) than seasonally (between sampled months). Trophic relationships in both estuaries demonstrated that organic matter is transferred to higher trophic positions mainly through benthic pathways. This shows the flexibility of these species to share resources and to exploit temporary peaks in prey populations. The present results showed that extensive disturbance in intertidal habitats from both estuaries may potentially change the balance of organic matter in the base of these complex food webs.  相似文献   

Benthic habitat mapping: Concerns using a combined approach (acoustic, sediment and biological data)     

Rosa Freitas  Fernando Ricardo  Fbio Pereira  Leandro Sampaio  Susana Carvalho  Miguel Gaspar  Victor Quintino  Ana Maria Rodrigues 《Estuarine, Coastal and Shelf Science》2011,92(4):72

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Differences in the variability of measured and simulated tropospheric ozone mixing ratios over the Paso del Norte Region     

William R. Stockwell  Rosa M. Fitzgerald  Duanjun Lu  Roberto Perea 《Journal of Atmospheric Chemistry》2013,70(1):91-104

The objective of this study is to present differences in the variability of observed and ozone-mixing ratios simulated by a three-dimensional atmospheric chemical model using two chemical mechanisms. In this study the Comprehensive Air Quality Model with Extensions is used to make ozone simulations with the Carbon Bond mechanism, versions 4 and 5. The Paso del Norte region is used as a test-bed for these simulations. The shared variance between the simulations and measurements is typical for air quality models ranging from 0.51 to 0.86 for both mechanisms. The smallest mean normalized gross error is about 31 % with CB4 but the normalized bias is over 30 % as well. Boundary conditions, emissions and other factors affect the levels of ozone of the simulated mixing ratios and therefore error and bias but these factors have a much less affect on the simulated ozone variability. The differences in the ozone variability of the measurements and the simulations are very large and different for the two chemical mechanisms. There are many more instances of low ozone mixing ratios in the measurements than in the simulated ozone. One possible explanation is that these differences are due to problems associated with comparing point measurements with grid averages. A more disturbing possibility is that the bias could be due to the procedures used in the development and testing of air quality modeling systems. Air quality mechanisms are evaluated against environmental chamber data where the chemistry occurs at high concentrations and this may lead to a systematic positive bias in ozone simulations.  相似文献   

Investigating the potential for marine resource protection through environmental service markets: An exploratory study from La Paz,Mexico     

Rhona F. Barr  Susana Mourato 《Ocean & Coastal Management》2009,52(11):568-577

Marine Protected Areas (MPAs) have long been advocated as effective management vehicles for promoting long-term conservation of marine resources and biodiversity. However MPAs are failing in their conservation goals, impeded by insufficient funds and a heavy reliance by low-income populations on natural resources.Investigation into a potential payment for environmental services (PES) program for marine protection was conducted in La Paz, Baja California Sur, Mexico. Surveys elicited tourists' willingness to pay (WTP) to reduce fishing pressure in Espíritu Santo Marine Park. Interviews with local fishermen investigated necessary levels of compensation in order to cease fishing, by proxy of required salaries in alternative employment outside of the fishing sector.Results indicated that required compensation values outweighed WTP by the tourist sector. Median WTP per trip amounted to US$12.50 and US$30, additional to pre-existing price, for day excursions and longer trips respectively. Median willingness to accept of fishermen was approximately US$135 per week, at time of survey, and required compensation was US$60 per week. Aggregated median WTP was able to cover annual compensation costs for approximately half of the fishing population. That fish stocks were not in collapse, thereby not creating sufficient scarcity and decreasing opportunity costs, and potential high transaction costs were identified as constraints of the proposed PES scheme.However, PES for marine protection should not be dismissed entirely; sites which are less productive and where fishermen's opportunity costs are low will be more suited to such a compensation scheme. Furthermore PES can work alongside existing markets.  相似文献   

Estimation of Heat Sources in Planetary Crusts from Isotherm Depth,Surface Heat Flow,and Crustal Thickness     

Ruiz  Javier  Tejero  Rosa 《Earth, Moon, and Planets》2002,91(3):185-193

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