Gas in early-type galaxies: cross-fuelling in late-type–early-type pairs?     

H. Cullen  P. Alexander  M. Clemens 《Monthly notices of the Royal Astronomical Society》2006,366(1):49-57

We present  ¹²CO ( J = 1–0)  and  ¹²CO ( J = 2–1)  observations of eight early-type galaxies, forming part of a sample of interacting galaxies, each consisting of one late- and one early-type system. All of the early-type galaxies observed are undetected in CO to low levels, allowing us to place tight constraints on their molecular gas content. Additionally, we present H  i absorption data for one system. The implications for possible gas transfer from the late- to the early-type galaxy during the interaction are discussed.  相似文献   

Impact of climate change on Pacific Northwest hydropower   总被引：2，自引：0，他引：2  

Matthew S. Markoff  Alison C. Cullen 《Climatic change》2008,87(3-4):451-469

The Pacific Northwest (PNW) hydropower resource, central to the region’s electricity supply, is vulnerable to the impacts of climate change. The Northwest Power and Conservation Council (NWPCC), an interstate compact agency, has conducted long term planning for the PNW electricity supply for its 2005 Power Plan. In formulating its power portfolio recommendation, the NWPCC explored uncertainty in variables that affect the availability and cost of electricity over the next 20 years. The NWPCC conducted an initial assessment of potential impacts of climate change on the hydropower system, but these results are not incorporated in the risk model upon which the 2005 Plan recommendations are based. To assist in bringing climate information into the planning process, we present an assessment of uncertainty in future PNW hydropower generation potential based on a comprehensive set of climate models and greenhouse gas emissions pathways. We find that the prognosis for PNW hydropower supply under climate change is worse than anticipated by the NWPCC’s assessment. Differences between the predictions of individual climate models are found to contribute more to overall uncertainty than do divergent emissions pathways. Uncertainty in predictions of precipitation change appears to be more important with respect to impact on PNW hydropower than uncertainty in predictions of temperature change. We also find that a simple regression model captures nearly all of the response of a sequence of complex numerical models to large scale changes in climate. This result offers the possibility of streamlining both top-down impact assessment and bottom-up adaptation planning for PNW water and energy resources.  相似文献   

Nonstationarity of turbulent heat fluxes at Summit,Greenland     

Nicolas J. Cullen  Konrad Steffen  Peter D. Blanken 《Boundary-Layer Meteorology》2007,122(2):439-455

Turbulence data collected over a total of 25 days during two summers are used to describe processes responsible for the nonstationarity of turbulent sensible heat fluxes at Summit, Greenland. A stationarity test shows that about 40% of the data are classified as nonstationary. Three main factors are explored to account for the large fraction of nonstationary runs: (1) intermittency of turbulence in stable conditions, (2) changes in net all-wave radiation in response to cloud forcing, and (3) diurnal trends in stability. A classification procedure that accounts for the intermittent nature of turbulence shows that during stable, nonstationary conditions 50% of the total sensible heat flux is realized in 22% of the sampling time. Intermittency often occurs at Summit during periods characterized by weak and irregular horizontal winds in combination with strong stability. Rapid changes in net all-wave radiation in response to cloud forcing results in nonstationarity during unstable conditions. Between 0930–1130 and 1900–1930 UTC turbulent heat fluxes are not only small in magnitude but also typically change sign, with nonstationarity during these periods often as high as 65%. These results should help resolve some of the present uncertainties in obtaining reliable fluxes at this site, in particular under stable atmospheric conditions.  相似文献   

Epidermal, hepatocellular and cholangiocellular carcinomas in brown bullheads, Ictalurus nebulosus, from industrially polluted black river, Ohio     

John C. Harshbarger  Linda J. Cullen  Michael J. Calabrese  Phyllis M. Spero  Paul C. Baumann  William K. Parland 《Marine environmental research》1984,14(1-4)

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Techniques for determination of trace metals in small samples of size-fractionated particulate matter: phytoplankton metals off central California     

Jay T. Cullen  Robert M. Sherrell 《Marine Chemistry》1999,67(3-4)

The oceanic biogeochemical cycles of many trace elements are dominated by their association with the growth, death, consumption and sinking of phytoplankton. The trace element content of marine phytoplankton reflects nutritional status, species composition, surface area to volume ratios, and interactions with bioactive and toxic elements in the ambient seawater. Despite the ecological and environmental importance of trace element assimilation by autotrophs, there are few modern measurements of trace elements in phytoplankton assemblages from the natural environment. Here we introduce a new method for collection and analysis of size-fractionated particulate samples from practical seawater volumes. We pay particular attention to accurate determination of trace element filter blanks which are typically the limiting factor for analysis of such samples. Metals were determined at very low detection limits by high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) for 11 elements (Ag, Al, Cd, Co, Cr, Cu, Fe, Mn, U, Zn and P, which is used as a biomass normalizer) in three types of polymer filters (0.45, 5.0, and 53 μm pore size) and a quartz fiber filter (0.8 μm pore size). To place these new determinations in a practical context, results are presented for a vertical profile of samples filtered from 1–4 l of coastal seawater (0.3–1.0 mg total solid dry weight) at a station off central California. The results demonstrate that the blanks of the evaluated filter types, precleaned appropriately, are sufficiently low to allow accurate determination of the trace metal content of three size-classes of phytoplankton. At the Pacific station, measured phytoplankton Zn content (as Zn/P) agrees with values predicted from single-species culture studies growing at seawater Zn concentrations expected for coastal waters. The new method has utility as a generally applicable and simple size fractionation technique, and allows determination of natural and pollutant elements in small samples of phytoplankton and particles in coastal, estuarine and offshore marine regimes.  相似文献   

Sewage treatment wasted--the Victoria (BC, Canada) example     

Chapman PM  Cullen J  Garrett C  Littlepage J  Pedersen T  Varela D  Macdonald RW  Thomson R  Parsons T 《Marine pollution bulletin》2008,56(11):1815-1816

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Axial and transverse deep-water sediment supply to syn-rift fault terraces: Insights from the West Xylokastro Fault Block,Gulf of Corinth,Greece     

Timothy M. Cullen  Richard E. Ll. Collier  Robert L. Gawthorpe  David M. Hodgson  Bonita J. Barrett 《Basin Research》2020,32(5):1105-1139

Deep-water syn-rift systems develop in partially- or transiently-linked depocentres to form complicated depositional architectures, which are characterised by short transport distances, coarse grain sizes and a wide range of sedimentary processes. Exhumed systems that can help to constrain the tectono-stratigraphic evolution of such systems are rare or complicated by inversion tectonics. Here, we document a mid-Pleistocene deep-water syn-rift system fed by Gilbert-type fan deltas in the hangingwall of a rift margin fault bounding the West Xylokastro Horst block, on the southern margin of the Gulf of Corinth, Greece. Structural and stratigraphic mapping combined with digital outcrop models permit observations along this syn-rift depositional system from hinterland source to deep-water sink. The West Xylokastro Fault hangingwall is filled by two distinct sediment systems; an axial system fed by coarse-grained sediment gravity flows derived from fault-tip Gilbert-type fan deltas and a lateral system dominated by mass transport deposits fed from an evolving fault-scarp apron. Abrupt changes in stratigraphic architecture across the axial system are interpreted to record changes in relative base level, sediment supply and tectonics. Locally, depositional topography and intra-basinal structures controlled sediment dispersal patterns, from bed-scale infilling of local rugose topography above mass transport complexes, to basin-scale confinement from the fault scarp apron. These acted to generate a temporally and spatially variable, heterogeneous stratigraphic architecture throughout the basin-fill. The transition of the locus of sedimentation from a rift margin to a fault terrace through the syn-sedimentary growth of a basinward fault produced regressive surfaces updip, which manifest themselves as channels in the deep-water realm and acted to prograde the system. We present a new conceptual model that recognises coeval axial and transverse systems based on the stratigraphic architecture around the West Xylokastro fault block that emphasizes the lateral and vertical heterogeneity of rift basin-fills with multiple entry points.  相似文献   

Study on diel rhythm of chlorophyll a and photosynthesis in nearshore waters of Qingdao   总被引：1，自引：0，他引：1  

Mao Xinghu  Zhu Mingyuan  Yang Xiaolong  Hao Yawei  John Cullen 《海洋学报(英文版)》1998,17(2):243-254

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Making Sense of Claims across Institutional Divides: critical PGIS and mapping customary land in Timor-Leste     

Alexander Cullen 《The Australian geographer》2015,46(4):473-490

This article explores land-tenure issues faced by Timor-Leste, specifically with reference to customary land, and the significance of mapping in resolving those difficulties. A critical review is undertaken of the pitfalls of Indigenous mapping and applications of Participatory Geographic Information Systems (PGIS) to achieve sensitive and empowering outcomes for customary groups seeking land claims. A methodology for mapping customary land in Timor-Leste is described and an analysis of the author's on-the-ground research is presented. Although the importance of customary institutions for rural land management across Timor-Leste is ascertained, this article does not advance a definitive land rights framework for the country or prescribe national mapping of customary areas. Instead, it argues for a mapping methodology to support land-use decision-making that can make sense of Indigenous knowledge and appropriate cultural practices in rural land-use claims. Identified as crucial in the process is the equal value attributed to evidence presented in myriad forms that may act as key information bridges across epistemological divides and knowledges. PGIS is a potentially important tool for resolving land-use conflicts in rural Timor-Leste when resolution occurs within a formalised institutional framework.  相似文献   

Calibration of a coupled biological-physical model for prediction in a coastal inlet     

M. Guarracino  M. DowdJ. Sheng  J.J. Cullen 《Continental Shelf Research》2011,31(16):1713-1727

We describe a numerical forecast system designed for prediction of physical and biological dynamics of a coastal inlet. It is based on a coastal ocean observatory that was located at Lunenburg Bay, Nova Scotia, Canada. Biological, chemical, optical, and physical measurements were collected from instrumented moorings, weekly sampling and detailed surveys from 2002 through 2007. Here we present a framework for calibration and evaluation of an ecosystem model using data from the summer of 2007. A three-dimensional hydrodynamic model was coupled to a simple biological (Nutrients-Phytoplankton-Detritus) model; a simple model was used so results could be compared directly to observed biological and chemical variables using skill scores as a first step toward data-assimilation modeling. As a complement to this analysis, variability of model output, e.g., the nutrient limitation term, was examined to understand the modeled biological response to the simulated physical environment. Skill scores based on variances in observed and simulated time-series of biological components were also investigated. Coastal upwelling/downwelling simulated through this model has been found to increase modeled biological activity in the bay. Also model skill in reproducing the observed patterns in nutrients and phytoplankton has been increased due to the restoring conditions for biology set up at the open ocean boundaries of the bay.  相似文献