Induction of zona radiata and vitellogenin genes in estradiol and nonylphenol exposed male sheepshead minnows (Cyprinodon variegatus)     

Iris Knoebl  Michael J. Hemmer  Nancy D. Denslow   《Marine environmental research》2004,58(2-5):547

Several genes normally induced by estradiol (E₂) in female fish, those for vitellogenins (VTGs) and zona radiata proteins (ZRPs), are also inducible in males exposed to estrogenic chemicals. Male sheepshead minnows (SHM) were exposed to both E₂ and para-nonylphenol (NP), at several doses and times to determine a dose-response. Quantitative real time PCR was used to measure mRNA for VTG1, VTG2, ZRP2 and ZRP3. Both E₂ and NP elicited a dose-response increase in all of the mRNAs tested. Exposure to both chemicals resulted in VTG2 expression at about a 10-fold lower level than VTG1, and ZRP2 expression at a lower level than ZRP3.  相似文献   

Tropical cyclones,climate change,and scientific uncertainty: what do we know,what does it mean,and what should be done?     

Iris Grossmann  M. Granger Morgan 《Climatic change》2011,108(3):543-579

The question of whether and to what extent global warming may be changing tropical cyclone (TC) activity is of great interest to decision makers. The presence of a possible climate change signal in TC activity is difficult to detect because interannual variability necessitates analysis over longer time periods than available data allow. Projections of future TC activity are hindered by computational limitations and uncertainties about changes in regional climate, large scale patterns, and TC response. This review discusses the state of the field in terms of theory, modeling studies and data. While Atlantic TCs have recently become more intense, evidence for changes in other basins is not persuasive, and changes in the Atlantic cannot be clearly attributed to either natural variability or climate change. However, whatever the actual role of climatic change, these concerns have opened a “policy window” that, if used appropriately, could lead to improved protection against TCs.  相似文献   

Future makers or future takers? A scenario analysis of climate change and the Great Barrier Reef     

Erin Bohensky  James R.A. ButlerRobert Costanza  Iris BohnetAurélie Delisle  Katharina FabriciusMargaret Gooch  Ida KubiszewskiGeorge Lukacs  Petina PertEric Wolanski 《Global Environmental Change》2011,21(3):876-893

The extent to which nations and regions can actively shape the future or must passively respond to global forces is a topic of relevance to current discourses on climate change. In Australia, climate change has been identified as the greatest threat to the ecological resilience of the Great Barrier Reef, but is exacerbated by regional and local pressures. We undertook a scenario analysis to explore how two key uncertainties may influence these threats and their impact on the Great Barrier Reef and adjacent catchments in 2100: whether (1) global development and (2) Australian development is defined and pursued primarily in terms of economic growth or broader concepts of human well-being and environmental sustainability, and in turn, how climate change is managed and mitigated. We compared the implications of four scenarios for marine and terrestrial ecosystem services and human well-being. The results suggest that while regional actions can partially offset global inaction on climate change until about mid-century, there are probable threshold levels for marine ecosystems, beyond which the Great Barrier Reef will become a fundamentally different system by 2100 if climate change is not curtailed. Management that can respond to pressures at both global and regional scales will be needed to maintain the full range of ecosystem services. Modest improvements in human well-being appear possible even while ecosystem services decline, but only where regional management is strong. The future of the region depends largely on whether national and regional decision-makers choose to be active future ‘makers’ or passive future ‘takers’ in responding to global drivers of change. We conclude by discussing potential avenues for using these scenarios further with the Great Barrier Reef region's stakeholders.  相似文献   

A combined ToF‐SIMS and EMP/SEM study of a three‐phase symplectite in the Los Angeles basaltic shergottite     

Detlef Rost  Thomas Stephan  Ansgar Greshake  Jörg Fritz  Iris Weber  Elmar K. Jessberger  Dieter Stöffler 《Meteoritics & planetary science》2009,44(8):1225-1237

Abstract— A rare three‐phase symplectite consisting of Ca‐rich pyroxene, Fe‐rich olivine, and a silica phase is frequently found rimming pyroxene in the Martian meteorite Los Angeles. This assemblage is usually interpreted as the breakdown product of metastable pyroxferroite, a very rare pyroxenoid mineral itself. However, its origin is not entirely understood, mainly because the extremely small average size of the constituent phases represents a challenge for precise high‐resolution analysis. In addition to electron microbeam methods, the present study uses time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) to overcome the limits of spatial resolution and to comprehensively study this mineral assemblage. The prevailing breakdown hypothesis is supported by the following results: (1) The three symplectite phases are very homogenous in composition from 100 μm down to the micrometer scale. (2) The silica phase could be shown to be almost pure SiO². (3) The symplectite bulk composition is consistent with pyroxferroite. Sub‐micrometer sized Ti‐oxide grains are found within the symplectite (but not within the Ca‐rich pyroxene) and probably represent a minor breakdown phase in addition to the three main phases.  相似文献   

Reconstructing ancient topography through erosion modelling   总被引：1，自引：1，他引：1  

Iris Peeters  Tom Rommens  Gert Verstraeten  Gerard Govers  Anton Van Rompaey  Jean Poesen  Kristof Van Oost 《Geomorphology》2006,78(3-4):250-264

One of the main aims of geomorphology is to understand how geomorphic processes change topography over long time scales. Over the last decades several landscape evolution models have been developed in order to study this question. However, evaluation of such models has often been very limited due to the lack of necessary field data. In this study we present a topography based hillslope erosion and deposition model that is based on the WATEM/SEDEM model structure and works on a millennial time scale. Soil erosion, transport and deposition are calculated using slope and unit contributing area. The topography is iteratively rejuvenated by taking into account modelled erosion and deposition rates, thereby simulating topographic development backwards in time. A first attempt has been made to spatially evaluate the model, using detailed estimates for historical soil erosion and sediment deposition volumes, obtained from an augering campaign in a small catchment in the Belgian Loess Belt. The results show that the model can simulate realistic soil redistribution patterns. However, further research is necessary in order to deal with artificial flaws that cause routing problems and significantly influence results. Common problems and issues related to this type of backward modelling are also discussed.  相似文献   

Shallow landslide susceptibility mapping using high-resolution topography for areas devastated by super typhoon Haiyan     

Maricar L. Rabonza  Raquel P. Felix  Alfredo Mahar Francisco A. Lagmay  Rodrigo Narod C. Eco  Iris Jill G. Ortiz  Dakila T. Aquino 《Landslides》2016,13(1):201-210

Super typhoon Haiyan, considered as one of the most powerful storms recorded in 2013, devastated the central Philippines region on 8 November 2013 with damage amounting to more than USD 2 billion. Hardest hit is the province of Leyte which is located in central Philippines. Rehabilitation of the areas that were devastated requires detailed hazard maps as a basis for well-planned reconstruction. Along with severe wind, storm surge, and flood hazard maps, detailed landslide susceptibility maps for the cities and municipalities of Leyte (7246.7 km²) province are necessary. In order to rapidly assess and delineate areas susceptible to rainfall-induced shallow landslides, Stability INdex MAPping (SINMAP) software was used over a 5-m Interferometric Synthetic Aperture Radar (InSAR)-derived digital terrain model (DTM) grid. Topographic, soil strength, and hydrologic parameters were used for each pixel of a given DTM grid to compute for the corresponding factor of safety. The landslide maps generated using SINMAP are highly consistent with the landslide inventory derived from high-resolution satellite imagery from 2002 to 2014 with a detection percentage of 97.5 % and missing factor of 0.025. These demonstrate that SINMAP performs well despite the lack of an extensive geotechnical and hydrological database in the study area. The detailed landslide susceptibility classification is useful to identify safe and unsafe areas for reconstruction and rehabilitation efforts. These maps complement the debris flow and structurally controlled landslide hazard maps that are also being prepared for rebuilding Haiyan’s devastated areas.  相似文献   

Changes in Snowmelt Runoff Timing in Western North America under a `Business as Usual' Climate Change Scenario   总被引：1，自引：1，他引：1  

Iris T. Stewart  Daniel R. Cayan  Michael D. Dettinger 《Climatic change》2004,62(1-3):217-232

Spring snowmelt is the most important contribution of many rivers in western North America. If climate changes, this contribution may change. A shift in the timing of springtime snowmelt towards earlier in the year already is observed during 1948–2000 in many western rivers. Streamflow timingchanges for the 1995–2099 period are projected using regression relationsbetween observed streamflow-timing responses in each river, measured by the temporal centroid of streamflow (CT) each year, and local temperature (TI) and precipitation (PI) indices. Under 21st century warming trends predicted by the Parallel Climate Model (PCM) under business-as-usual greenhouse-gas emissions, streamflow timing trends across much of western North America suggest even earlier springtime snowmelt than observed to date. Projected CT changes are consistent with observed rates and directions of change during the past five decades, and are strongest in the Pacific Northwest, Sierra Nevada, and Rocky Mountains, where many rivers eventually run 30–40 daysearlier. The modest PI changes projected by PCM yield minimal CT changes. The responses of CT to the simultaneous effects of projected TI and PI trends are dominated by the TI changes. Regression-based CT projections agree with those from physically-based simulations of rivers in the Pacific Northwest and Sierra Nevada.  相似文献   

An Experimental Apparatus for Laboratory and Field-Based Perfusion of Sediment Porewater with Dissolved Tracers     

Amber Hardison  Craig Tobias  Jennifer Stanhope  Elizabeth Canuel  Iris Anderson 《Estuaries and Coasts》2011,34(2):243-255

The water–sediment interface is a dynamic zone where the benthic and pelagic environments are linked through exchange and recycling of organic matter and nutrients. However, it is often difficult to measure rate processes in this zone. To that end, we designed an experimental apparatus for continuous and homogeneous perfusion of sediment porewater with dissolved conservative (SF₆, Rhodamine WT dye) and isotopic (H¹³CO₃⁻ and ¹⁵NH₄⁺) tracers to study nitrogen and carbon cycling by the sediment microbial community of shallow illuminated sediments. The perfusionator consists of a 60-cm ID × 60-cm high cylinder that includes a reservoir for porewater at the base of the sediment column. Porewater amended with conservative and stable isotopic tracers was pumped through a mixing reservoir and upward through the overlying sediments. We tested the perfusionator in a laboratory setting, as part of an outdoor mesocosm array, and buried in coastal sediments. Conservative and isotopic tracers demonstrated that the porewater tracers were distributed homogeneously through the sediment column in all settings. The perfusionator was designed to introduce dissolved stable isotope tracers but is capable of delivering any dissolved ionic, organic, or gaseous constituent. We see a potentially wide application of this technique in the aquatic and marine sciences in laboratory and field settings.  相似文献   

Spatial Integration of Arab Migrants in a Jewish New Town     

Iris Graicer 《The Professional geographer》1992,44(1):45-56

This paper examines the residential migration of Arabs from Nazareth, Israel, to the nearby Jewish new town of Nazerat Illit. Nazareth is an Arab town with a mixed Moslem and Christian population, while Nazerat Illit is predominantly Jewish. In many towns in Israel with a mixed Jewish and Arab population, the Arabs are concentrated in “ghetto enclaves.” However, in Nazerat Illit Arabs are dispersed throughout the town and are spatially integrated with the Jewish populatio. Possible explanations for the different pattern include the spatial proximity of the origin and destination settlements, the socio-economic similarity of the absorbing and absorbed population, and the dependence of the majority population on the minority for improvement in the former's apartment standards.  相似文献   

Perspectives for Hamburg as a port city in the context of a changing global environment     

Iris Grossmann 《Geoforum》2008,39(6):2062-2072

During recent decades, most European river-port cities and also many seaport cities have undergone a major transition towards a service-centred, rather than industrially-based metropolis, offering a high quality urban environment with a revitalised waterfront. Hamburg is one of the few river-port cities that have chosen the course of port expansion instead. This paper discusses the consequences of current global technological, organisational and economic developments for the port. Changing requirements imply rising monetary and land-use costs and environmental and social impacts, and also entail the risk that the port may not be able to fulfil new requirements and could thus lose market shares to coastal competitors. More importantly, the world-wide economic shift towards the service sector has affected port-dependent jobs in two ways: Directly port-dependent jobs have been reduced to a fraction, while many indirectly port-dependent jobs no longer require physical proximity of the port. Those benefits that continue to arise tend to spread over a much larger geographical region, while the port’s costs remain locally concentrated. Given the increasing competition between world-wide metropolitan regions that seek to establish themselves in new sectors and attract a qualified workforce, it is particularly relevant for Hamburg to account for these changes and to incorporate an assessment of the port’s changing costs and benefits into planning processes. To date, this task has received little attention from the city.  相似文献