Use of cartographic images by expert and novice field geologists in planning fieldwork routes

Topographic maps and aerial photographs are particularly useful when geoscientists are faced with fieldwork tasks such as selecting paths for observation, establishing sampling schemes, or defining field regions. These types of images are crucial in bedrock geologic mapping, a cognitively complex field-based problem-solving task. Geologic mapping requires the geologist to correctly identify rock types and three-dimensional bedrock structures from often partial or poor-quality outcrop data while navigating through unfamiliar terrain. This paper compares the walked routes of novice to expert geologists working in the field (n = 66) with the results of a route planning and navigation survey of a similar population of geologists (n = 77). Results show clearly that those geologists with previous mapping experience make quick and decisive determinations about field areas from available imagery and maps, regardless of whether they are or not physically present in the field area. Recognition of geologic features enabled experts to form and verbalize a specific plan for travel through a landscape based on those features. Novices were less likely to develop specific travel route plans and were less likely to identify critical landscape cues from aerial photographs.     

Testing for Sediment Acidification Effects on Within-Season Variability in Juvenile Soft-Shell Clam (<Emphasis Type="Italic">Mya arenaria</Emphasis>) Abundance on the Northern Shore of the Bay of Fundy

Soft-shell clams (Mya arenaria) can serve important ecological roles in intertidal mudflats and are an important economic and recreational resource in the northwestern Atlantic. However, environmental factors affecting newly-settled and juvenile clam abundances within a given settlement season remain uncertain. We conducted a field study assessing relationships between juvenile soft-shell clam abundance and spatial, temporal, and environmental variables in coastal mudflats of the northern shore of the Bay of Fundy. Sediment pH and low-tide water temperature (tide pools) were monitored in situ on a biweekly–monthly basis over the course of the M. arenaria settlement season in 2012 at four study sites to quantify diel variation in sediment pH and temperature. Core samples were also collected to quantify M. arenaria (<6 mm) abundance. Sea-surface and air temperature, and in situ sediment pH and water temperature were then used to predict clam abundance. Sediment pH was spatially and temporally variable, while in situ temperature was stable and declined over the sampling season. Akaike’s information criterion model selection indicated that models incorporating site, date, and air temperature best predicted 2012 recruitment patterns in linear models when all variables were included. When only environmental variables were included, the best linear model included minimum air temperature and sediment pH. When data were averaged across dates for each site to remove potential temporal effects, mean clam abundance displayed a significant positive relationship with sediment pH and sediment grain size, but not minimum air temperature. The results of this study suggest that sediment pH and/or sediment grain size may influence within-season juvenile soft-shell clam abundances across mudflats in the Bay of Fundy. Field experiments at the same (or similar) sites are now needed to confirm the mechanism driving the observed relationships.     

Photometric catalogue of Shakhbazian compact groups of galaxies. IV.

The fourth part of the photometric catalogue of Shakhbazian compact groups of galaxies contains optical and geometrical properties of another 26 groups (Shkh 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 357). As in the previous papers photometric data were obtained from the COSMOS/UKST catalogue of the Southern sky with δ ± +2°30'. The survey of compact galaxy groups by Shakhbazian, Petrosian, Baier, and Tiersch is a basis for studying physical properties of such groups.     

The spectra of three newly discovered high-redshift quasars

Spectra of three high-redshift quasars discovered on low-dispersion objective prism plates were obtained. We present the emission line identifications and redshifts of the objects. Equivalent widths, line widths and low-resolution line profiles are given characterizing the quasar emission region. The Lyα and CIV equivalent widths indicate that the considered quasars are luminous objects at high redshift. Both these equivalent widths are too low by a factor 4, whereas the N V/Lyα ratio is 5 times larger than predicted by the photoionisation models. The line profiles are compared with logarithmic, electron-scattering and Gaussian profiles. In all the spectra rich absorption line systems are evident.     

Integration of optical and Synthetic Aperture Radar (SAR) imagery for delivering operational annual crop inventories

Agriculture plays a critical role within Canada’s economy and, as such, sustainability of this sector is of high importance. Targeting and monitoring programs designed to promote economic and environmental sustainability are a vital component within Canada’s agricultural policy. A hierarchy of land information, including up to date information on cropping practices, is needed to measure the impacts of programs on land use decision-making and to gauge the environmental and economic benefits of these investments. A multi-year, multi-site research activity was completed to develop a robust methodology to inventory crops across Canada’s large and diverse agricultural landscapes. To move towards operational implementation the methodology must deliver accurate crop inventories, with consistency and reliability. In order to meet these operational requirements and to mitigate risk associated with reliance on a single data source, the methodology integrated both optical and Synthetic Aperture Radar (SAR) imagery. The results clearly demonstrated that multi-temporal satellite data can successfully classify crops for a variety of cropping systems present across Canada. Overall accuracies of at least 85% were achieved, and most major crops were also classified to this level of accuracy. Although multi-temporal optical data would be the preferred data source for crop classification, a SAR-optical dataset (two Envisat ASAR images and one optical image) provided acceptable accuracies and will mitigate risk associated with operational implementation. The preferred dual-polarization mode would be VV–VH. Not only were these promising classification results repeated year after year, but the target accuracies were met consistently for multiple sites across Canada, all with varying cropping systems.