Re-thinking colonialism to prepare for the impacts of rapid environmental change   总被引：1，自引：1，他引：0  

Nicholas James Reo  Angela K. Parker 《Climatic change》2013,120(3):671-682

This essay demonstrates how key concepts from ecology can be applied within historical analyses in order to gain insights regarding contemporary environmental change. We employ a coupled human and natural systems conceptual framework in a nascent historical analysis of rapid societal and environmental change in colonial New England, where European colonization led to stark and rapid transformations. Introduced diseases reduced indigenous communities to a fraction of their pre-contact levels. European agriculture and associated pest species, deforestation and overharvest of ecologically influential species were among key aspects of the rapid changes in colonial New England. Cross-continental biotic introductions initiated reinforcing feedback loops that accelerated the transition of human and natural systems into novel states. Integrating colonial history and ecology can help identify important interactions between human and natural systems useful for contemporary societies adjusting to environmental change.  相似文献   

Adaptation of the antioxidant defence system in hydrothermal-vent mussels (Bathymodiolus azoricus) transplanted between two Mid-Atlantic Ridge sites     

Rui Company  Angela Serafim  Richard Cosson  Aline Fiala-Médioni  David R. Dixon  & Maria João Bebianno 《Marine Ecology》2007,28(1):93-99

The vent mussel Bathymodiolus azoricus is the dominant member of the Northern Mid‐Atlantic Ridge (MAR) hydrothermal megafauna, and lives in an environment characterized by temporal and spatial variations in the levels of heavy metals, methane and hydrogen sulphide, substances which are known to increase reactive oxygen species levels in the tissues of exposed organisms. To evaluate the effects of two contrasting hydrothermal environments on the antioxidant defence system of this vent mussel species, a 2‐week transplant experiment was carried out involving mussels collected from the relatively deep (2300 m), and chemical rich, Rainbow vent field. These were transplanted to the shallower (1700 m), and relatively less toxic, Lucky Strike vent field. To achieve this objective, levels of superoxide dismutase, catalase (CAT), total glutathione peroxidase (GPx), selenium‐dependent glutathione peroxidase and lipid peroxidation (LPO) were measured in the gills and mantle tissues of resident and transplant mussels before and after the transplant experiment. With the exception of CAT, the gills of the transplanted mussels had significantly higher antioxidant enzyme activity compared with the basal levels in the donor (Rainbow) and recipient (Lucky Strike) populations; whereas the antioxidant enzyme levels in the mantle tissues of the transplants reflected the baseline levels of activity in the native Lucky Strike mussels after 2 weeks. In contrast, LPO levels were significantly higher in both tissue types in the transplants than in either the source or the recipient populations, which suggested a response to hydrostatic pressure change (note, the transplant animals were brought to the surface for transportation between the two vent fields). The fact that the Rainbow mussels survived the transplant experience indicates that B. azoricus has a very robust constitution, which enables it to cope behaviourally, physiologically and genetically with the extreme conditions found in its naturally contaminated deep‐sea environment.  相似文献   

9C: a survey of radio sources at 15 GHz with the Ryle Telescope   总被引：1，自引：0，他引：1  

Elizabeth M. Waldram  Guy G. Pooley  Keith J. B. Grainge  Michael E. Jones  Richard D. E. Saunders  Paul F. Scott  Angela C. Taylor 《Monthly notices of the Royal Astronomical Society》2003,342(3):915-925

The fields chosen for the first observations of the cosmic microwave background with the Very Small Array have been surveyed with the Ryle Telescope at 15 GHz. We have covered three regions around RA  00^h 20^m Dec. +30°  , RA  09^h 40^m Dec. +32°  and RA  15^h 40^m Dec. +43° (J2000.0)  , an area of  520 deg²  . There are 465 sources above the current completeness limit of  ≈25 mJy  , although a total of  ≈760  sources have been detected, some as faint as 10 mJy. This paper describes our techniques for observation and data analysis; it also includes source counts and some discussion of spectra and variability. Preliminary source lists are presented.  相似文献   

A Survey for EHB Stars in the Galactic Bulge     

Donald M. Terndrup  Deokkeun An  Angela Hansen  Ruth C. Peterson  Alistair R. Walker  Elaine M. Sadler 《Astrophysics and Space Science》2004,291(3-4):247-252

We present a progress report on an extensive survey to find and characterize all types of horizontal-branch stars in the nuclear bulge of the Galaxy. We have obtained wide, shallow imaging in UBV of ≈12 square degrees in the bulge, with follow-up spectroscopy for radial velocities and metal abundance determinations. We have discovered a number of metal-rich blue HB stars, whose presence in the bulge is expected by the interpretation of the extragalactic ultraviolet excess. Very deep images have been obtained in UBV and SDSS u along the bulge minor axis, which reveal a significant number of EHB candidates fainter than B=19, i.e., with the same absolute magnitudes as EHB stars in several globular clusters.  相似文献   

Gamma-ray and synchrotron emission from neutralino annihilation in the Large Magellanic Cloud     

Argyro Tasitsiomi  Jennifer Gaskins  Angela V. Olinto   《Astroparticle Physics》2004,21(6):637-650

We calculate the expected flux of γ-ray and radio emission from the LMC due to neutralino annihilation. Using rotation curve data to probe the density profile and assuming a minimum disk, we describe the dark matter halo of the LMC using models predicted by N-body simulations. We consider a range of density profiles including the NFW profile, a modified NFW profile proposed by Hayashi et al. (2003) to account for the effects of tidal stripping, and an isothermal sphere with a core. We find that the γ-ray flux expected from these models may be detectable by GLAST for a significant part of the neutralino parameter space. The prospects for existing and upcoming Atmospheric Cherenkov Telescopes (ACTs) are less optimistic, as unrealistically long exposures are required for detection. However, the effects of adiabatic compression due to the baryonic component may improve the chances for detection by ACTs. The maximum flux we predict is well below EGRET's measurements and thus EGRET does not constrain the parameter space. The expected synchrotron emission generally lies below the observed radio emission from the LMC in the frequency range of 19.7–8550 MHz. As long as σv<2×10⁻²⁶ cm³ s⁻¹ for a neutralino mass of 50 GeV, the observed radio emission is not primarily due to neutralinos and is consistent with the assumption that the main source is cosmic rays. We find that the predicted fluxes, obtained by integrating over the entire LMC, are not very strongly dependent on the inner slope of the halo profile, varying by less than an order of magnitude for the range of profiles we considered.  相似文献   

Zodiacal Infrared Foreground Prediction for Space Based Infrared Interferometer Missions     

M. Landgraf  R. Jehn 《Astrophysics and Space Science》2001,278(3):357-365

The zodiacal foreground for a highly sensitive space infrared interferometer is predicted for various observing locations. For the predictions we use a model that was derived from measurements of the Cosmic Background Explorer (COBE). We find that at a wavelength of10 μm 96% of the sky is darker than 1 MJy sr^-1 for observations in the ecliptic plane at 5 AU, and 83% is darker than 0.1 MJy sr^-1.At 1 AU, however, always more than 50% of the sky are brighter than1 MJy sr^-1, even if the observations are made from 30^° or60^° of latitude above the ecliptic plane, at 10 or 20 μm.Thus, according to the employed model, the foreground reduction by increasing the heliocentric distance of the observing location is more effective than by increasing the latitude. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Dodging alligators,rattlesnakes, and backyard docks: a political ecology of sweetgrass basket-making and conservation in the South Carolina Lowcountry,USA     

Patrick T. Hurley  Angela C. Halfacre 《GeoJournal》2011,76(4):383-399

There is growing recognition among political ecologists of the need to examine shifting natural resource regimes and their effects on livelihoods in “First World” places. This emerging literature has variously examined the “Third World within,” the persistence of “subsistence activities” in the “First World,” and the “reterritorialization” of land tenure and access. However, much of this work has tended to focus on traditional extractive industries in the American West, indigenous claims to lands and resources in the U.S. and Canada, and non-timber resources on public lands. In contrast, we use a case study of African-American sweetgrass basket-makers, associated with the Gullah culture, in South Carolina’s lowcountry to examine the ways in which ongoing amenity-driven residential development is fundamentally reshaping resource access on private lands. Historically, basket-makers harvested the materials (primarily sweetgrass or Mulenbergia filipes) needed for their culturally important art form from accessible, rural, and privately held tracts of land in close proximity to their communities, but development pressures and changes in resident interpretation of property rights has decreased access to basket-making resources. The case is particularly illuminating, as it examines the emergence of ‘conservation subdivisions’ in the region and raises important questions about what “rural uses” and users are being conserved through responses to exurban, suburban, and urban development in formerly rural areas.  相似文献   

Phyllosilicates synthesis: a way of accessing edges contributions in NMR and FTIR spectroscopies. Example of synthetic talc     

Angela Dumas  François Martin  Christophe Le Roux  Pierre Micoud  Sabine Petit  Eric Ferrage  Jocelyne Brendlé  Olivier Grauby  Mike Greenhill-Hooper 《Physics and Chemistry of Minerals》2013,40(4):361-373

A series of new-generation synthetic talcs were prepared by varying the hydrothermal synthesis duration from a few hours up to 2 months. Crystallinity and particle size analysis of the synthetic products were evaluated by photon correlation spectroscopy, transmission electron microscopy, differential thermal analysis and unoriented X-ray diffraction, and then analyzed by various spectroscopic methods such as Fourier transformed infrared spectroscopy and solid-state ¹H and ²⁹Si magic angle spinning nuclear magnetic resonance. The new process for preparing synthetic talcs allows to obtain single-phased particles which after few hours grow heterogeneously and simultaneously in both the c* direction and the (ab) plan. Fine particles, observed for whatever the synthesis duration, lead to the presence of numerous sheet edges surfaces due to particle size which represents the main difference with natural talc. Spectroscopy data show the influence of the fine particles on signals and highlight that synthetic talc characterization is a potential tool for better understanding crystal chemistry of natural talc.  相似文献   

Revisiting hydrocarbons source appraisal in sediments exposed to multiple inputs     

Carlos G. Massone  Angela de L.R. Wagener  Henrique Monteiro de Abreu  Álvaro Veiga 《Marine pollution bulletin》2013

The aim of this work was to test the efficiency of statistical methods as compared to the traditional diagnostic ratios to improve hydrocarbon source identification in sediments subjected to multiple inputs. Hydrocarbon determination in Guanabara Bay sediments pointed out high degradation and ubiquitous petrogenic pollution through the presence of high unresolved complex mixture. Polycyclic aromatic hydrocarbon (PAHs) ratios suggested pervasive contamination derived from combustion in all sediments and failed discriminating samples despite the specificity of sources in different sampling sites. Principal component analysis (PCA) effectively distinguished the petrogenic imprint superimposed to the ubiquitous combustion contamination, since this technique reduces the influence of PAHs distribution which is common to all samples. PCA associated to multivariate linear regression (MLR) allowed a quantitative assessment of sources confirming predominance of the pervasive contaminant component superimposed to a generalized petrogenic imprint. The pervasive component derives from combustion contributions as well as from differential PAHs degradation.  相似文献   

Macroseismic field of the October 27, 2004 Vrancea (Romania) moderate subcrustal earthquake     

Angela Petruta Constantin  Aurelian Pantea 《Journal of Seismology》2013,17(4):1149-1156

On October 27, 2004, a moderate size earthquake occurred in the Vrancea seismogenic region (Romania). The Vrancea seismic zone is an area of concentrated seismicity at intermediate depths beneath the bending area of the southeastern Carpathians. The 2004 M _w?=?6 Vrancea subcrustal earthquake is the largest seismic event recorded in Romania since the 1990 earthquakes. With a maximum macroseismic intensity of VII Medvedev–Sponheuer–Kárník (MSK-64) scale, the seismic event was felt to a distance of 600 km from the epicentre. This earthquake caused no serious damage and human injuries. The main purpose of this paper is to present the macroseismic map of the earthquake based on the MSK-64 intensity scale. After the evaluation of the macroseismic effects of this earthquake, an intensity dataset has been obtained for 475 sites in the Romanian territory. Also, the maximum horizontal accelerations recorded in the area by the K2 network are compared to the intensity values.  相似文献