2,596 research outputs found
Field Recognition of Adult \u3ci\u3eAcentrella\u3c/i\u3e and \u3ci\u3eHeterocloeon\u3c/i\u3e (Ephemeroptera: Baetidae)
The highly developed anterior process of the mesothorax, is described as a useful field character for identifying adults of Acentrella and Heterocloeon in the Nearctic. This presumed adult synapomorphy suggests a sister relation- ship of the two genera
Design of the materials experiment carrier for on-orbit servicing
This paper discussed the MEC system and its mission from the viewpoint of orbit servicing. Information is provided on MEC system requirements, design for on orbit servicing, on orbit servicing operations and rationale and servicing costs
Differential Shoot Feeding by Adult \u3ci\u3eTomicus Piniperda\u3c/i\u3e (Coleoptera: Scolytidae) in Mixed Stands of Native and Introduced Pines in Indiana.
The larger pine shoot beetle Tomicus piniperda, a native bark beetle of Europe and Asia, was found in North American Christmas tree plantations in 1992 in Ohio. Subsequent surveys found it in six U.S. states and in one Canadian province. The first natural area where Tomicus was found to be established was at the Indiana Dunes State Park, in northwestern Indiana near the Lake Michigan shoreline. Pine stands were surveyed for fallen shoots to determine the extent and range of shoot feeding in the park. Within the study area adult Tomicus fed on the shoots of all native pines (Pinus banksiana, P. resinosa. and P. strobus.), as well as the European species (P. sylvestris). More fallen shoots were collected from both P. resinosa and P. sylvestris than expected from their basal areas in the sampled stands. This contrasted with P. banksiana and P. strobus whose shoots were underrepresented relative to their basal areas. The relatively high numbers of fallen shoots found for P. resinosa suggests that red pines in the Great Lakes region will easily support populations of T. piniperda
Barbaetis: A New Genus of Eastern Nearctic Mayflies (Ephemeroptera: Baetidae)
The new genus Barbaetis Waltz and McCafferty, and new species Barbaetis benfieldi Kennedy are described from larvae collected from the New River, Virginia. Barbaetis is easily told from Baetis by the presence of procoxal osmobranchia. Cladistics of B. benfieldi, related Pseudocloeon species, and the lutheri and pavidus complexes of Baetis are presented and indicate the need for further taxonomic revision. The habitat of B. benfieldi is described in terms of several ecological parameters. The new species demonstrates a univoltine life history with postembryonic development restricted to a short springtime period
Summary: Remote sensing soil moisture research
During the 1969 and 1970 growing seasons research was conducted to investigate the relationship between remote sensing imagery and soil moisture. The research was accomplished under two completely different conditions: (1) cultivated cropland in east central South Dakota, and (2) rangeland in western South Dakota. Aerial and ground truth data are being studied and correlated in order to evaluate the moisture supply and water use. Results show that remote sensing is a feasible method for monitoring soil moisture
Changes in ponderosa pine forests of the Mt. Trumbull Wilderness
Ponderosa pine forests in the Mt. Trumbull Wilderness on the Arizona Strip have become dense with young trees and highly susceptible to catastrophic wildfire due to exclusion of the natural frequent-fire regime. As part of a broader regional ecological restoration study, the Mt. Trumbull Wilderness was sampled for fire scarred trees, vegetation, and fuels in 1997 and 1999. Reconstructed fire histories show that fires recurred about every 4.4 years prior to settlement, with larger fires burning every 9.5 years. Frequent fires ceased after 1863 in the Mt. Trumbull Wilderness, coincident with the time of Euro-American settlement around 1870, beginning a fire-free period that has lasted up to the present except for a few small fires and a larger 1989 wildfire. Current forests are dense, averaging approximately 1,200 trees/ha, and dominated by small trees. Throughout the wilderness, tree canopy cover averages over 65(percent) and tree basal area is high, 35- 36 m2/ha. Understory plant cover is about 20(percent) and understory species diversity averages 11.4 species/sample plot. Living and dead fuels, including plants, woody debris, and the forest floor, will easily support high-intensity wildfires. In contrast, the presettlement forest was relatively open, with tree density of approximately 62 trees/ha and basal area averaging 8.9 m2/ha, dominated by large ponderosa pine trees. In ecological terms, prospects are good for restoring the Mt. Trumbull Wilderness to emulate the ecological structure and fire disturbance regime of the presettlement reference condition. The current forest condition is perhaps least affected by recent degradation of any site in the Uinkaret Mountains. However, ecological information is only one component contributing to the debate over appropriate management values and practices in wilderness areas on public lands
Globalising assessment: an ethnography of literacy assessment, camels and fast food in the Mongolian Gobi
What happens when standardised literacy assessments travel globally? The paper presents an ethnographic account of adult literacy assessment events in rural Mongolia. It examines the dynamics of literacy assessment in terms of the movement and re-contextualisation of test items as they travel globally and are received locally by Mongolian respondents. The analysis of literacy assessment events is informed by Goodwin’s ‘participation framework’ on language as embodied and situated interactive phenomena and by Actor Network Theory. Actor Network Theory (ANT) is applied to examine literacy assessment events as processes of translation shaped by an ‘assemblage’ of human and non-human actors (including the assessment texts)
Seeding versus natural regeneration: a comparison of vegetation change following thinning and burning in ponderosa pine
The decision whether to seed with native species following restoration treatments should be based on existing vegetation, species present in or absent from the soil seed bank, past management history, microclimate conditions and soils. We installed three permanent monitoring plots in two areas (total 18.6 ha) at Mt. Trumbull, AZ. Trees were thinned and the sites burned in 1996 and 1997. A 5 ha area was seeded with native shrub, grass and forb species; the remaining 13.6 ha were unseeded. Pretreatment species richness ranged from none to five species per plot. We recorded 13 graminoid and eight shrub species in the seeded area, and four graminoid and four shrub species in the unseeded area. The greatest increase in species richness in both seeded and unseeded plots occurred approximately 1.8 years posttreatment. Perennial native species dominated plant cover by 2.8 years, although annual native forbs dominate the soil seed bank. Perennial grasses are nearly absent from the seed bank. The seeded area had the highest diversity, but it also had twice as many nonnative species (14 versus 7 in the unseeded plots). By August 1999, maximum species richness reached 51 species on the seeded plot. Of these species, 80 percent were native. Although seeding increases diversity, it may also have the long-term tradeoff of introducing new genotypes and species, both native and nonnative
Shape of the 8B Alpha and Neutrino Spectra
The beta-delayed alpha spectrum from the decay of 8B has been measured with a
setup that minimized systematic uncertainties that affected previous
measurements. Consequently the deduced neutrino spectrum presents much smaller
uncertainties than the previous recommendation. The 8B neutrino spectrum is
found to be harder than previously recommended with about (10-20)% more
neutrinos at energies between 12-14 MeV. The efficiencies of the 37Cl, 71Ga,
40Ar, and SuperKamiokande detectors are respectively, 3.6%, 1.4%, 5.7% and 1.8%
larger than previously thought.Comment: 4 pages, 5 figure
Studies of turbulence and transportation in Alcator C-Mod ohmic plasmas with phase contrast imaging and comparisons with gyrokinetic simulations
- …
