Is the Sabine-Neches estuary net heterotrophic or autotrophic? A reply to the comment by Flinn et al.     

Thomas S. Bianchi  M. Baskaran  M. Ravichandran 《Estuaries and Coasts》1998,21(4):839-841

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Photochemical changes in chemical markers of sedimentary organic matter source and age     

Lawrence M. Mayer  Linda L. Schick  Thomas S. Bianchi  Laura A. Wysocki 《Marine Chemistry》2009,113(1-2):123-128

Several chemical markers of organic matter source and age are shown to be susceptible to light-induced alteration. To test for the photochemical lability of markers previously employed for sediments from the Louisiana coastal zone, we subjected sediments under resuspension conditions to simulated sunlight, and monitored changes in C:N and Br:OC ratios, δ¹³C, Δ¹⁴C, and lignin composition. Markers of terrigenous origin (high C:N, lignin) decreased and δ¹³C became enriched in sediments containing primarily terrigenous organic matter, while a marker of marine organic matter (Br:OC) decreased in samples containing significant contributions from this source. Preferential loss of ¹⁴C from all sediments indicated enhanced photochemical lability of organic matter of relatively recent origin, consistent with the changes in chemical markers. Most, but not all, experimental alterations are consistent with field distributions of these markers. Relatively small experimental changes in the markers in combination with confounding processes in the environment, however, prevent these parallel trends from providing any more than a consistency test for the importance of photochemical reactions in this region.  相似文献   

Tilt Angles of Solar Filaments over the Period of 1919 – 2014     

Andrey G. Tlatov  Kirill M. Kuzanyan  Valeria V. Vasil’yeva 《Solar physics》2016,291(4):1115-1127

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Short- and long-term response of phytoplankton to ENSO in Prydz Bay,Antarctica: Evidences from field measurements,remote sensing data and stratigraphic biomarker records     

Jun Zhao  Hans-Ulrich Peter  Haisheng Zhang  Zhengbing Han  Chuanyu Hu  Peisong Yu  Bing Lu  Thomas S. Bianchi 《中国海洋大学学报(英文版)》2014,13(3):437-444

The study provides one of the first lines of evidence showing linkages between Antarctic phytoplankton abundance and composition in response to ENSO, based on historical reconstruction of sediment biomarkers. In addition to sediment biomarkers, field measured and remote sensing data of phytoplankton abundance were also recorded from Prydz Bay, Eastern Antarctica. Com-munity structure of field measured phytoplankton showed significant El Ni？o/La Ni？a-related succession during 1990 to 2002. In general, the number of algae species decreased during El Ni？o and La Ni？a years compared to normal years. Austral summer monthly variation of remotely sensed chlorophyll-a （Chl-a）, particulate organic carbon （POC）, and sea surface temperature （SST） indicated that ENSO impacted the timing of phytoplankton blooms during 2007 to 2011. Phytoplankton blooms （indicated by Chl-a and POC） preceded the increases in SST during El Ni？o years, and lagged behind the SST increases during La Ni？a years. Stratigraphic record of marine sedimentary lipid （brassicasterol, dinosterol and alkenones） biomarkers inferred that the proportions of different algae （diatoms, dinoflagellates and haptophytes） changed significantly between El Ni？o and La Ni？a events. The relative proportion of diatoms increased, with that of dinoflagellates being decreased during El Ni？o years, while it was reversed during La Ni？a years.  相似文献   

The circumnuclear X-ray reflectors in NGC 1068 and the Circinus galaxy     

Stefano Bianchi    Giorgio Matt  Kazushi Iwasawa 《Monthly notices of the Royal Astronomical Society》2001,322(3):669-680

The ASCA and BeppoSAX spectra of the Circinus galaxy and NGC 1068 are analysed and compared with photoionization models based on cloudy . In the case of Circinus, a single, mildly ionized reflector can account for the line spectrum, while in NGC 1068 at least three different reflectors (with different ionization states) are needed. We suggest that the reflector in Circinus and the low ionized one in NGC 1068 are the inner and visible part of the material responsible for the X-ray absorption. With this assumption, we estimate for the inner radius of the absorber a value of 0.2 pc for Circinus and of a few parsecs for NGC 1068.  相似文献   

Do bilateral trade relationships influence the distribution of CDM projects?     

Valeria Costantini  Giorgia Sforna 《Climate Policy》2013,13(5):559-580

The use of the Clean Development Mechanism (CDM) is increasingly widespread in developing countries. However, CDM projects are still far from being an effective development activity due to the uneven distribution of these projects in a few relatively well-off economies. One potential cause of this imbalance is analysed in terms of the trade relationships between developed and developing countries. By applying a gravity model to a panel dataset, well-established export flows from developed economies towards developing countries are shown to explain why a large proportion of CDM projects are unevenly geographically distributed. This kind of lock-in effect regarding the CDM between developed and developing countries could be avoided by both enhancing the institutional framework in developing countries that host CDM projects and reinforcing compulsory rules for CDM destinations in the least-developed economies.  相似文献   

The Ultraviolet sky surveys: filling the gap in our view of the Universe     

Luciana Bianchi 《Astrophysics and Space Science》2009,320(1-3):11-19

The GALEX mission is performing imaging and spectroscopic surveys of the sky at Ultraviolet wavelengths, and providing unprecedented sky maps in two UV bands, far-UV and near-UV, and catalogs of UV sources. I will describe the major surveys accomplished so far, and results in investigating the nature of the UV sources. The UV surveys, linked to a multi-wavelength archive, offer great sensitivity to detect and characterize several classes of astrophysical objects, such as low-redshift QSOs, star-forming galaxies, and white dwarfs (WD) in the Milky Way. Efforts towards obtaining a significant census of WDs from GALEX imaging data are described in particular. A dedicated, deep survey of nearby galaxies provides a snapshot of their recent star formation, shedding new light on the process of star formation and its modalities in different environments and conditions. Deep GALEX data revealed young stellar populations in extreme outskirts of spiral galaxies, previously thought to be stable against star formation given their low density. UV measurements for millions of nearby and distant galaxies map the history and probe the causes of star formation in the Universe over the redshift range z=0–2.  相似文献   

Stellar sources of dust in the high-redshift Universe     

Rosa Valiante  Raffaella Schneider  Simone Bianchi  Anja C. Andersen 《Monthly notices of the Royal Astronomical Society》2009,397(3):1661-1671

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Gravitational wave backgrounds and the cosmic transition from Population III to Population II stars     

Stefania Marassi  Raffaella Schneider  Valeria Ferrari 《Monthly notices of the Royal Astronomical Society》2009,398(1):293-302

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On the peculiar properties of the narrow-line quasar PG 1543+489     

Cristian Vignali  Enrico Piconcelli  Stefano Bianchi  Giovanni Miniutti 《Monthly notices of the Royal Astronomical Society》2008,388(2):761-769

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