Seabird distribution on the Humboldt Current in northern Chile in relation to hydrography, productivity, and fisheries     

Weichler  Tanja; Garthe  Stefan; Luna-Jorquera  Guillermo; Moraga  Julio 《ICES Journal of Marine Science》2004,61(1):148-154

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Surficial Hydrocarbon Seep Infauna from the Blake Ridge (Atlantic Ocean, 2150 m) and the Gulf of Mexico (690–2240 m)     

Christie A. Robinson  Joan M. Bernhard  Lisa A. Levin  Guillermo F. Mendoza  & Jessica K. Blanks 《Marine Ecology》2004,25(4):313-336

Abstract.  Infauna, including foraminifera and metazoans, were enumerated and identified from five types of seep habitats and two adjacent non-seep habitats. Collections were made with the deep submergence research vessel 'Alvin' from three areas of active seepage in the Gulf of Mexico (Alaminos Canyon [2220 m], Atwater Canyon [1930 m], and Green Canyon lease block 272 [700 m]) and on the Blake Ridge Diapir [2250 m], which is located off the southeastern coast of the United States. The seep habitats sampled included four types of microbial mats ( Beggiatoa , Thioploca , thin and thick Arcobacter ) and the periphery of a large mussel bed. Sediments under large rhizopod protists, xenophyophores, were sampled adjacent to the mussel bed periphery. A non-seep site, which was >1 km away from active seeps, was also sampled for comparison. Densities of most taxa were higher in the Gulf of Mexico seeps than in Blake Ridge samples, largely because densities in the thick microbial mats of Blake Ridge were significantly lower. Diversity was higher in the Thioploca mats compared to other microbial-mat types. Within an ocean basin ( i.e. , Atlantic, Gulf of Mexico) we did not observe significant differences in meiofaunal or macrofaunal composition in Beggiatoa versus Thioploca mats or thin versus thick Arcobacter mats. Foraminifera represented up to 16% of the seep community, a proportion that is comparable to their contribution at adjacent non-seep communities. In general, the observed densities and taxonomic composition of seep sites at the genus level was consistent with previous observations from seeps ( e.g. , the foraminifers Bolivina and Fursenkoina , the dorvilleid polychaete Ophryotrocha ).  相似文献   

Studies of multiple stellar systems – III. Modulation of orbital elements in the triple-lined system HD 109648     

Saurabh Jha  Guillermo Torres  Robert P. Stefanik  David W. Latham  Tsevi Mazeh 《Monthly notices of the Royal Astronomical Society》2000,317(2):375-384

The triple-lined spectroscopic triple system HD 109648 has one of the shortest periods known for the outer orbit in a late-type triple, 120.5 d, and the ratio between the periods of the outer and the inner orbits is small, 22:1. With such extreme values, this system should show orbital element variations over a time-scale of about a decade. We have monitored the radial velocities of HD 109648 with the CfA Digital Speedometers for 8 yr, and have found evidence for modulation of some orbital elements. While we see no definite evidence for modulation of the inner binary eccentricity, we clearly observe variations in the inner and the outer longitudes of periastron, and in the radial velocity amplitudes of the three components. The observational results, combined with numerical simulations, allow us to put constraints on the orientation of the orbits.  相似文献   

Building participatory landscape-based conservation alternatives: A case study of Michoacán, Mexico     

Alejandro Velzquez  Eva M. Cu-Br  Alejandra Larrazbal  Neyra Sosa  Jos Luis Villaseor  Michael McCall  Guillermo Ibarra-Manríquez 《Applied geography (Sevenoaks, England)》2009,29(4):513-526

Michoacán, as one of the most species-rich provinces of Mexico and with high levels of endemism, was used for testing the potential of a conservation approach based on biodiversity as determined by scientists and local stakeholder's preferences. The resulting zones covered over 17% of the area of Michoacán in 18 zones. As a result of this study the first “large” tropical dry forest biosphere reserve in Mexico is currently being established. In conclusion, landscape-based conservation zoning based on local stakeholders' perspectives as well as on critical biodiversity indicators, proved to be effective for achieving science-based and politically acceptable nature conservation schemes.  相似文献   

The evolution of superbubbles and the detection of Lyα in star-forming galaxies     

Guillermo Tenorio-Tagle  Sergey A. Silich  Daniel Kunth  Elena Terlevich  Roberto Terlevich † 《Monthly notices of the Royal Astronomical Society》1999,309(2):332-342

The detection of Ly α emission in star-forming galaxies in different shapes and intensities (always smaller than predicted for case B recombination) has puzzled the astronomical community for more than a decade. Here we use two-dimensional calculations to follow the evolution of superbubbles and of the H  ii regions generated by the output of UV photons from massive stars. We show the impact caused by massive star formation in the ISM of different galaxies and we look at the conditions required to detect Ly α emission from a nuclear H  ii region, and the variety of profiles that may be expected as a function of time.  相似文献   

Analysis of pathfinder SST algorithm for global and regional conditions     

Ajoy Kumar  Peter Minnett  Guillermo Podestá  Robert Evans  Katherine Kilpatrick 《Journal of Earth System Science》2000,109(4):395-405

As part of the Pathfinder program developed jointly by National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA) a large database ofin situ sea surface temperature (SST) measurements coincident with satellite data is now available to the user community. The Pathfinder Matchup Database (PMDB) is a multi-year, multi-satellite collection of coincident measurements from the Advanced Very High Resolution Radiometer (AVHRR) and broadly distributed buoy data (matchups). This database allows the user community to test and validate new SST algorithms to improve the present accuracy of surface temperature measurements from satellites. In this paper we investigate the performance of a global Pathfinder algorithm to specific regional conditions. It is shown that for zenith angles less than 45°, the best-expected statistical discrepancy between satellite and buoy data is about ∼ 0.5 K. In general, the bias of the residuals (satellite — buoy) is negative in most regions, except in the North Atlantic and adjacent seas, where the residuals are always positive. A seasonal signal in SST residuals is observed in all regions and is strongest in the Indian Ocean. The channel-difference term used as a proxy for atmospheric water vapor correction is observed to be unresponsive for columnar water vapor values greater than 45 mm and high zenith angles. This unresponsiveness of the channels leads to underestimation of sea surface temperature from satellites in these conditions.  相似文献   

El Niño and La Niña influence on mean river flows of southern South America in the 20th century     

Guillermo J. Berri  Emilio Bianchi  Gabriela V. Müller 《水文科学杂志》2019,64(8):900-909

The influence of the El Niño Southern Oscillation (ENSO) phenomenon on monthly mean river flows of 12 rivers in the extreme south of South America in the 20th century is analysed. The original dataset of each river is divided into two subsets, i.e. warm ENSO events or El Niño, and cold ENSO events or La Niña. The elements of the subsets are composites of 24 consecutive months, from January of the year when the ENSO event begins to December of the following year. The ENSO signal is analysed by comparing the monthly mean value of each subset to the long-term monthly mean. The results reveal that, in general, monthly mean El Niño (La Niña) river flows are predominantly larger (smaller) than the long-term monthly mean in the rivers studied. The anomalies are more evident during the second half of the year in which the event starts and the first months of the following year.  相似文献   

A proposal for boundary delimitation for integrated coastal zone management initiatives     

Pau Balaguer  Rafael Sard  Maurici Ruiz  Amy Diedrich  Guillermo Vizoso  Joaquin Tintor 《Ocean & Coastal Management》2008,51(12):806-814

ICZM relies heavily on the definition of major multidisciplinary characteristics/elements of the coastal area of interest. Usually, only terrestrial boundaries are considered, which tend to respond to a specific sectoral problem and can be determined by administrative limits. In this study, we propose a method for establishing a decision-making tool to inform boundary delimitation for ICZM initiatives that is proactive and widely applicable as opposed to reactive and problem specific. This method integrates environmental, economic and societal characteristics of the marine and terrestrial boundaries of the coastal zone, starting at the boundary of the jurisdictional zone of influence (shoreline units), increasing in detail through the definition of their influential areas from jurisdictional, environmental or socio-economic perspectives (functional areas) and, within them, specifying the finest scale at which relevant indicator data may be obtained (analysis units).  相似文献   

Progress towards instrument miniaturisation for mid-IR long-baseline interferometry     

Lucas Labadie  Stefano Minardi  Guillermo Martín  Robert R. Thomson 《Experimental Astronomy》2018,46(3):433-445

We report recent results on passive mid-infrared integrated optics from the project “Advanced Laser-writing for Stellar Interferometry” and shortly describe the perspectives of their hybridisation with active components for the benefit of the spectro-interferometry technique.  相似文献   

A Europe–South America network for climate change assessment and impact studies     

Jean-Philippe Boulanger  G. Brasseur  Andrea Fabiana Carril  Manuel de Castro  Nicolas Degallier  Carlos Ereño  H. Le Treut  Jose Antonio Marengo  Claudio Guillermo Menendez  Mario Nestor Nuñez  Olga C. Penalba  Alfredo Luis Rolla  Matilde Rusticucci  Rafael Terra 《Climatic change》2010,98(3-4):307-329

The goal of the CLARIS project was to build an integrated European–South American network dedicated to promote common research strategies to observe and predict climate changes and their consequent socio-economic impacts taking into account the climate and societal peculiarities of South America. Reaching that goal placed the present network as a privileged advisor to contribute to the design of adaptation strategies in a region strongly affected by and dependent on climate variability (e.g. agriculture, health, hydro-electricity). Building the CLARIS network required fulfilling the following three objectives: (1) The first objective of CLARIS was to set up and favour the technical transfer and expertise in earth system and regional climate modelling between Europe and South America together with the providing of a list of climate data (observed and simulated) required for model validations; (2) The second objective of CLARIS was to facilitate the exchange of observed and simulated climate data between the climate research groups and to create a South American high-quality climate database for studies in extreme events and long-term climate trends; (3) Finally, the third objective of CLARIS was to strengthen the communication between climate researchers and stakeholders, and to demonstrate the feasibility of using climate information in the decision-making process.  相似文献