W. D. Lambert et A. Marussi 《Journal of Geodesy》1952,26(2):178-179

Sans résumé Secrétaire de la Section I. Triangulations de l’Association Internationale de Géodésie  相似文献   

Developing a Learning Progression for Place: A Provocation and a Response     

David Lambert 《The Journal of geography》2018,117(3):122-124

The purpose of this short article is to offer a critical perspective on Larsen and Harrington's ambitious and stimulating review article. It does so by drawing a distinction between teaching and learning and discussing how progression metaphors for describing the latter can distort the moral purpose of the former. My response to the provocation offered by the review article is to resist the temptation to urge yet more research effort on developing a learning progression for place and instead focus on what is required to teach about place effectively. This would need to be driven by clear teaching goals rather than some technical learning progression.  相似文献   

Macroseepage of methane and light alkanes at the La Brea tar pits in Los Angeles     

Derek?Weber  Bertha?A.?Marquez  Charnise?Taylor  Paul?Raya  Paul?Contreras  David?Howard  Ikenna?Nwachuku  Katie?Fusco  Fernanda?Morales  Lambert?A.?DoezemaEmail author 《Journal of Atmospheric Chemistry》2017,74(3):339-356

Geologic seepage of methane and light (C₂-C₅) alkanes was measured at the La Brea Tar Pits in Los Angeles. Samples were collected using flux chambers with stainless steel canisters and analyzed using gas chromatography. Average seepage rates from individual seepage sites were 970 ± 330 mg/h of methane, 14.0 ± 5.5 mg/h of ethane, 9.1 ± 3.7 mg/h of propane, 3.7 ± 1.6 mg/h of i-butane, 0.33 ± 0.16 mg/h of n-butane, 260 ± 120 μg/h of i-pentane, and 5.3 ± 1.9 μg/h of n-pentane, while maximum seepage rates exceeded 17 g/h of methane, 270 mg/h of ethane, 190 mg/h of propane, 95 mg/h of i-butane, 10 mg/h of n-butane, 7 mg/h of i-pentane, and 0.1 mg/h of n-pentane. These absolute fluxes have an additional unknown amount of error associated with them due to sampling methodology, and should be taken as the lower limit of emissions. Samples collected revealed generally dry gas, with high methane emissions relative to the light alkanes. Overall emissions from the tar pits were found to come not only from the active geologic seepage, but also from the outgassing of the standing asphalt at the site. Using the gas ratios, which are negligibly affected by errors introduced by sampling methodology, observed in this study, daily emissions of C₂ – C₅ alkanes from the La Brea area were estimated to be 4.7 ± 1.6 Mg, which represents 2–3 % of total emissions in the entire Los Angeles region.  相似文献   

Thallium in the solar atmosphere     

D. L. Lambert  E. A. Mallia  G. Smith 《Solar physics》1972,26(1):250-256

Umbral spectra are shown to contain an absorption feature attributable to the Tl i transition 6p ² P°_3/2–7s ² S _1/2 at 5350 Å. Analysis of the umbral spectrum suggests a solar abundance in the 0.72< log N(Tl)T<1.10 on the standard scale log N(H) = 12.00. Unidentified blends limit the accuracy of the abundance determination.  相似文献   

Relating groundwater to seasonal wetlands in southeastern Wisconsin, USA     

John D. Skalbeck  Donald M. Reed  Randall J. Hunt  Jamie D. Lambert 《Hydrogeology Journal》2009,17(1):215-228

Historically, drier types of wetlands have been difficult to characterize and are not well researched. Nonetheless, they are considered to reflect the precipitation history with little, if any, regard for possible relation to groundwater. Two seasonal coastal wetland types (wet prairie, sedge meadow) were investigated during three growing seasons at three sites in the Lake Michigan Basin, Wisconsin, USA. The six seasonal wetlands were characterized using standard soil and vegetation techniques and groundwater measurements from the shallow and deep systems. They all met wetland hydrology criteria (e.g., water within 30 cm of land surface for 5% of the growing season) during the early portion of the growing season despite the lack of appreciable regional groundwater discharge into the wetland root zones. Although root-zone duration analyses did not fit a lognormal distribution previously noted in groundwater-dominated wetlands, they were able to discriminate between the plant communities and showed that wet prairie communities had shorter durations of continuous soil saturation than sedge meadow communities. These results demonstrate that the relative rates of groundwater outflows can be important for wetland hydrology and resulting wetland type. Thus, regional stresses to the shallow groundwater system such as pumping or low Great Lake levels can be expected to affect even drier wetland types.  相似文献   

Rockfall Hazard Analysis From Discrete Fracture Network Modelling with Finite Persistence Discontinuities   总被引：2，自引：1，他引：1  

Cédric Lambert  Klaus Thoeni  Anna Giacomini  Davide Casagrande  Scott Sloan 《Rock Mechanics and Rock Engineering》2012,45(5):871-884

Developing an accurate representation of the rock mass fabric is a key element in rock fall hazard analysis. The orientation, persistence and density of fractures control the volume and shape of unstable blocks or compartments. In this study, the discrete fracture modelling technique and digital photogrammetry were used to accurately depict the fabric. A volume distribution of unstable blocks was derived combining polyhedral modelling and kinematic analyses. For each block size, probabilities of failure and probabilities of propagation were calculated. A complete energy distribution was obtained by considering, for each block size, its occurrence in the rock mass, its probability of falling, its probability to reach a given location, and the resulting distribution of energies at each location. This distribution was then used with an energy–frequency diagram to assess the hazard.  相似文献   

Light-induced bird strikes on vessels in Southwest Greenland     

Merkel FR  Johansen KL 《Marine pollution bulletin》2011,62(11):2330-2336

Light-induced bird strikes are known to occur when vessels navigate during darkness in icy waters using powerful searchlight. In Southwest Greenland, which is important internationally for wintering seabirds, we collected reports of incidents of bird strikes over 2-3 winters (2006-2009) from navy vessels, cargo vessels and trawlers (total n = 19). Forty-one incidents were reported: mainly close to land (<4 km, 78%), but one as far offshore as 205 km. Up to 88 birds were reported killed in a single incident. All occurred between 5 p.m. and 6 a.m. and significantly more birds were involved when visibility was poor (snow) rather than moderate or good. Among five seabird species reported, the common eider (Somateria mollissima) accounted for 95% of the bird casualties. Based on spatial analyses of data on vessel traffic intensity and common eider density we are able to predict areas with high risk of bird strikes in Southwest Greenland.  相似文献   

Distribution of axis-splitting in Mojave Desert shrub species along an elevational gradient     

S.E. Lambert  H.J. Schenk 《Journal of Arid Environments》2011,75(2):106-111

Although highly branched from the base, all shrubs have short main axes linking canopies to root systems. Main axes become increasingly segmented into independent canopy/stem/root segments as aridity increases across continents. The resulting hydraulic modularity has been proposed as an adaption to low soil moisture that prevents runaway embolism and minimizes risk of hydraulic failure. Here we test the hypotheses that (1) at a regional scale, the importance of axis-splitting species in communities declines with increasing elevation, as a proxy for precipitation, and (2) that this decline is explained by lower occurrence of low-elevation dominant species. We evaluated all species for axis splitting and determined importance values in plots along an elevational transect in the Mojave Desert. As predicted, as elevation increased, the total importance of axis-splitting species declined from 100% at low-elevation sites to 75% at the highest elevation site. However, this decline was not due solely to the decline of the lower elevation dominant species. At the high elevation site, the influx of new species resulted in a six-fold increase in species richness and almost all of the new high elevation woody eudicotyledonous species exhibited axis splitting; non-splitting species were represented by other growth forms.  相似文献   

Monitoring changes of ice streams using time series of satellite-altimetry-based digital terrain models     

Ute C. Herzfeld  Craig S. Lingle  Cecily Freeman  Chris A. Higginson  Michael P. Lambert  Li-Her Lee  Vera A. Voronina 《Mathematical Geology》1997,29(6):859-890

The Antarctic Ice Sheet plays a major role in the global system, and the large ice streams discharging into the circumpolar sea represent its gateways to the world’s oceans. Satellite radar altimeter data provide an opportunity for mapping surface elevation at kilometerresolution with meteraccuracy. Geostaristical methods have been developed for the analysis of these data. Applications to Seasat data and data from the Geosat Exact Repeat Mission indicate that the grounding line of Lambert Glacier/Amery Ice Shelf, the largest ice stream in East Antarctica, has advanced 10–12 km between 1978 and 1987–89. The objectives of this paper are to explore possibilities and limitations of satellite-altimetry-based mapping to capture changes for shorter time windows and for smaller areas, and to investigate some methodological aspects of the data analysis. We establish that one season of radar altimeter data is sufficient for constructing a map. This allows study of interannual variation and is the key for a limeseries analysis approach to study changes in ice streams. Maps of the lower Lambert Glacier and the entire Amery Ice Shelf are presented for austral winters 1978, 1987, 1988, and 1989. As a first step toward understanding the dynamics of the ice-stream/iceshelf system, elevation changes are calculated for grounded ice, the grounding zone, and floating ice. In the absence of (sufficient) surface gravity control for the Lambert Glacier/Amery Ice Shelf area, altimetry-based maps may facilitate improvement of geoid models as they provide constraints on the terrain correction in the inverse gravimetric problem.  相似文献   

A Raman spectroscopic study of shocked single crystalline quartz     

Paul F. McMillan  George H. Wolf  Phillipe Lambert 《Physics and Chemistry of Minerals》1992,19(2):71-79

We have carried out a Raman Spectroscopic study of single crystalline quartz samples shocked to peak pressures up to 31.4GPa. Samples shocked to above 22 GPa show shifts in peak positions consistent with the quartz being under tensile stress, and new broad bands associated with the formation of high density SiO₂ glass appear in the spectra. These changes are accompanied by an increase in the lattice parameters of the quartz. Formation of the diaplectic glass could be due to a metastable melting event, or spinodal lattice collapse on attainment of a mechanical stability limit of crystalline quartz, as suggested by previous studies of pressure-induced amorphization in static pressurization experiments on SiO₂ and GeO₂ polymorphs.  相似文献