Hα spectropolarimetry of B[e] and Herbig Be stars     

René D. Oudmaijer  Janet E. Drew 《Monthly notices of the Royal Astronomical Society》1999,305(1):166-180

  相似文献   

Numerical simulation of subsurface characterization methods: application to a natural aquifer analogue     

Janet Whittaker  Georg Teutsch 《Advances in water resources》1999,22(8):603

Information from an outcrop is used as an analogue of a natural heterogeneous aquifer in order to provide an exhaustive data set of hydraulic properties. Based on this data, two commonly used borehole based investigation methods are simulated numerically. For a scenario of sparse sampling of the aquifer, the process of regionalization of the borehole hydraulic conductivity values is simulated by application of a deterministic interpolation approach and conditioned stochastic simulations. Comparison of the cumulative distributions of particle arrival times illustrates the effects of the sparse sampling, the properties of the individual investigation methods and the regionalization methods on the ability to predict flow and transport behaviour in the real system (i.e. the exhaustive data set).  相似文献   

Effects of urbanization on river morphology of the Talar River,Mazandarn Province,Iran     

Saleh Yousefi  Hamid Reza Moradi  Saskia Keesstra  Hamid Reza Pourghasemi  Oldrich Navratil  Janet Hooke 《国际地球制图》2019,34(3):276-292

In the present study, we investigate the effects of urbanization growth on river morphology in the downstream part of Talar River, east of Mazandaran Province, Iran. Morphological and morphometric parameters in 10 equal sub-reaches were defined along a 11.5 km reach of the Talar River after land cover maps were produced for 1955, 1968, 1994, 2005 and 2013. Land cover types changed extremely during the study period. Residential lands were found to have increased in area by about 1631%, while forest land and riparian vegetation decreased in by approximately 99.9 and 96.2%, respectively. The results of morphometric and morphological factors showed that average channel width (W) for all 11.5 km of the study river decreased by 84% during the study period, while the flow length increased by about 2.14%.  相似文献   

Hybrid Neoliberalism: Implications for Sustainable Development     

Claudia Baldwin  Graham Marshall  Helen Ross  Jim Cavaye  Janet Stephenson  Lyn Carter 《社会与自然资源》2019,32(5):566-587

Neoliberalism is frequently blamed for challenges in achieving sustainable development; consequently some also question if sustainability is still a useful concept. Neoliberal influence on natural resource management has evolved over the last 30?years to a hybrid form that seeks to compensate for its negative social and environmental externalities. Through review of literature and critical analysis of three case studies of resource development in Australia and New Zealand, we argue that, in spite of modifications under hybrid approaches, neoliberalism still tests achievement of sustainability goals, due to privileging industry and shifting risk and costs to future generations, through inadequate regulation, neglect of public consultation, lack of transparency, and weak impact assessment. We suggest that while neoliberal approaches bring both benefits and disadvantages, sustainability principles must continue to be kept at the forefront of legislation, regulation and management.  相似文献   

Long-term trends and interannual variability of temperature in Drake Passage     

Janet Sprintall   《Progress in Oceanography》2008,77(4):316-330

Temperature data collected over the last 36 years (1969–2004) in Drake Passage are used to examine interannual temperature variation and long-term trends in the upper ocean. To reduce the effect of variation from different sampling locations and temporal variability introduced by meridional shifts in the Polar Front (PF), the data were divided into two sub-regions north (3800 temperature profiles) and south (3400) of the PF. Temperature anomalies were formed by removing a temporal mean field for each profile in each sub-region at 100 m depth intervals from the surface to 700 m. North of the PF, statistically significant warming trends of 0.02 °C yr⁻¹ were observed that were largely depth-independent between 100 and 700 m. A statistically significant cooling trend of −0.07 °C yr⁻¹ was observed at the surface south of the PF, which was smaller (−0.04 °C yr⁻¹) but still statistically significant when possible seasonal sampling biases were accounted for. The observed cooling at the surface and warming at depth is largely consistent with a poleward shift of the PF due to enhancement of westerly winds in the Southern Ocean, as recently suggested by models and observations. The observed annual temperature anomalies in the upper 400 m north of the PF and in the upper 100 m south of the PF are highly correlated to variability in sea ice, and also to climate indices of the Antarctic Oscillation and the El Niño Southern Oscillation. Variability in sea ice and temperature anomalies lag El Niño variability in the Pacific, with a phasing consistent with the observed cyclical patterns of sea ice and sea surface temperature associated with the Antarctic Circumpolar Wave or Antarctic Dipole Mode in the Southern Ocean. In contrast, the sea ice variability and temperature anomalies at all depths north of the PF and at 0–100 m depth south of the PF were primarily coincident with, or led the Antarctic Oscillation Index. No significant correlations were found with the large-scale climate variability indices in southern Drake Passage below 100 m depth, which is occupied by upper Circumpolar Deep Water (uCDW). This water mass is not formed locally, is largely isolated from the surface, and exhibits vertical and lateral homogeneity. Hence changes may be difficult to detect in the available measurements, and climate variation in the source water regions of uCDW may take a long time to reach Drake Passage.  相似文献   

Archaeological geophysics investigation of the Wright Brothers 1910 hangar site     

Dwain K. Butler  Janet E. Simms  Daryl S. Cook 《Geoarchaeology》1994,9(6):437-466

An archaeological geophysics investigation was conducted at the site of the Wright Brothers' 1910 hangar near Dayton, Ohio. The hangar was destroyed as part of base renovation during the buildup to World War II, and its exact location is unknown. The purpose of the investigation is to confirm the exact location of the hangar and to locate any buried artifacts from the Wright Brothers occupation of the site. Ground penetrating radar (GPR), electromagnetic, and magnetic surveys were conducted over a 68 × 100 m area, approximately centered on the suspected location of the hangar. Localized anomalies as well as areal anomalies are identified in the geophysical data. Rectangular anomalous areas are identified that are generally consistent with the suspected location of the hangar. A 1924 aerial photograph showing the hangar was digitally scanned and georeferenced to the site survey area. Two of the rectangular geophysical anomalous areas are consistent with the hangar location from the aerial photograph location. A third rectangular area, defined from GPR survey data, is immediately adjacent to the aerial photograph location. It is postulated that base engineers may have bulldozed the hangar debris onto an area adjacent to its original location and either burned it there or buried it in a trench. A prioritized exploratory program is proposed for investigating the sources of the geophysical anomalies. © 1994 John Wiley & Sons, Inc.  相似文献