1,591 research outputs found
Moose, Caribou, and Grizzly Bear Distribution in Relation to Road Traffic in Denali National Park, Alaska
Park managers are concerned that moose (Alces alces), caribou (Rangifer tarandus), and grizzly bears (Ursus arctos) may be avoiding areas along the 130 km road through Denali National Park as a result of high traffic volume, thus decreasing opportunities for visitors to view wildlife. A wildlife monitoring system was developed in 1996 that used 19 landscape level view sheds, stratified into four sections based on decreasing traffic along the road corridor. Data were collected from 22 samplings of all viewsheds during May-August in 1996 and 1997. In 1997, nine backcountry viewsheds were established in three different areas to determine whether density estimates for each species in the backcountry were higher than those for the same animals in similar road-corridor areas. Densities higher than those in the road corridor were found in one backcountry area for moose and in two backcountry areas for grizzly bears. None of the backcountry areas showed a higher density of caribou. We tested hypotheses that moose, caribou, and grizzly bear distributions were unrelated to the road and traffic. Moose sightings were lower than expected within 300 m of the road. More caribou and grizzly bears than expected occurred between 601 and 900 m from the road, while more moose and fewer caribou than expected occurred between 900 and 1200 m from the road. Bull moose in stratum 1 were distributed farther from the road than bulls and cows in stratum 4; cows in stratum 1 and bul1s in stratum 2 were distributed farther from the road than cows in stratum 4. Grizzly bears in stratum 2 were distributed farther from the road than bears in stratum 3. The distribution of moose sightings suggests traffic avoidance, but the spatial pattern of preferred forage may have had more of an influence. Caribou and grizzly bear distributions indicated no pattern of traffic avoidance.Les gérants du parc s'inquiètent du fait que l'orignal (Alces alces), le caribou (Rangifer tarandus) et le grizzli (Ursus arctos) pourraient éviter les zones bordant les 130 km de la route qui traverse le parc national Denali, en raison du volume élevé de circulation, ce qui diminue aussi pour les visiteurs les chances de voir la faune. Un système de surveillance de la faune a été mis sur pied en 1996, système qui faisait appel à 19 cabanes d'observation installées de niveau avec le paysage, réparties en quatre sections déterminées selon la décroissance de circulation le long du corridor routier. En 1996 et 1997, on a collecté les données de mai à août provenant de 22 échantillons prélevés à toutes les cabanes. En 1997, neuf cabanes d'arrière-pays ont été installées dans trois zones différentes, afin de déterminer si les estimations des densités pour chaque espèce étaient plus élevées dans l'arrière-pays que dans des zones semblables agissant comme corridors routiers. On a trouvé des densités plus élevées que celles dans le corridor routier pour l'orignal dans une zone d' arrière-pays, et pour le grizzli dans deux zones d'arrière-pays. Aucune des zones d'arrière-pays n'a montré une densité plus élevée pour le caribou. Nous avons testé les hypothèses que les distributions d'orignal, de caribou et de grizzli ne sont pas reliées à la présence de la route ni à la circulation. Les observations d'orignaux étaient moindres que prévu dans la zone s'étendant jusqu'à 300 m de la route. Il y avait plus de caribous et de grizzlis que prévu dans la zone s'étendant de 601 à 900 m de la route, tandis qu'il y avait plus d'orignaux et moins de caribous que prévu dans la zone s'étendant de 900 à 1200 m de la route. Les orignaux mâles dans la strate 1 étaient distribués plus loin de la route que les orignaux mâles et les femelles dans la strate 4; les femelles dans la strate 1 et les mâles dans la strate 2 étaient distribués plus loin de la route que les femelles dans la strate 4. Les grizzlis dans la strate 2 étaient distribués plus loin de la route que les ours dans la strate 3. La distribution des observations d'orignaux suggère que ces animaux évitent la circulation, mais la répartition spatiale de leurs herbes de prédilection pourrait constituer une influence majeure. La distribution du caribou et du grizzli n'a révélé aucun schéma d'évitement de la circulation
Where is the Theoretical Basis for Understanding and Measuring the Environment for Physical Activity?
Researchers are beginning to explore environmental correlates to further the field of physical activity research. Before interventions and experimental investigations can be undertaken, it is necessary to identify specific environmental features that are consistent correlates of physical activity. There has been a plethora of research measuring such cross-sectional associations since this field came to the fore in 2003. This paper posits that it is time for researchers to evaluate the state of knowledge, and suggests that future developments in this field focus on the theoretical bases for (i) measurement of the environment and (ii) understanding the links between perceptions of the environment and behaviour through psychological theories of cognition. Key theories considered include social ecology and the theory of planned behaviour. It is suggested that with a continued absence of a common conceptual framework, vocabulary and measurement tools the majority of studies may remain at a correlates stage. In highlighting issues with current methodologies, this commentary encourages more grounded theoretical approaches to the study of the environment and physical activity
Measuring soil bulk density profiles with a single probe gamma density gauge
Calibrating neutron depth gauges for measuring soil water content profiles requires
soil bulk density data. In this study, the feasibility of using a single probe gamma
density gauge to measure the soil wet bulk density was investigated for use in neutron
gauge calibration. The same sites, access tubes, and conventional gravimetric soil data
used for the ASCE Neutron Gauge Calibration Study were used for the Gamma Gauge
Study. Iterative procedures were successfully developed to calibrate the gamma
density gauge, and then to convert wet bulk density to dry bulk density data for the
three soil sites studied
Effect of moisture and bulk density sampling on neutron moisture gauge calibration
Three moisture and bulk density sampling methods were evaluated for use in
neutron gauge calibration. Each of the methods was comprised of a single
core or portions of a core taken during installation of a neutron access tube.
In addition to direct measurement of bulk density, the effect of using
"smoothed", "probable" and gamma-probe measured bulk density profiles was
evaluated. The use of these three alternative bulk density profiles in the
computation of volumetric moisture generally had insignificant effect on the
resulting neutron gauge calibration equation. The use of a depth-weighted
volumetric moisture profile generally improved calibration statistics, but reduced
slopes of neutron calibration equations (% moisture per count ratio). Overall,
a total core method which used a tractor-mounted, hydraulically operated
coring tool provided the most consistent calibrations with lowest standard errors
of estimate, although compression of soil along the perimeter of the cored hole
increased subsequent neutron count ratios. A "Madera" down-hole sampler
generally provided good calibrations, also. A third, small-volume, down-hole
sampler provided valid moisture and bulk density samples; however, the smaller
representative volume of the sampler relative to the sampling volume of neutron
gauges adversely affected slopes of some calibration equations
Error analysis of bulk density measurements for neutron moisture gauge calibration
Six bulk density sampling methods were evaluated for use in neutron gauge
calibration. All six methods provided estimates of bulk density which were
generally within 5% of bulk density profiles measured using a gamma probe.
Standard errors of estimate ranged from 3 to 7 %. When used with care,
downhole, coring, and drive samplers can be used to successfully measure soil
moisture and bulk density profiles for use in neutron probe calibration
Neurology
Contains reports on six research projects.U. S. Public Health Service (B-3055-4, B-3090-4, MH-06175-02)U. S. Air Force (AF49(638)-1313)U.S. Navy. Office of Naval Research (Nonr-1841(70)
HyspIRI High-Temperature Saturation Study
As part of the precursor activities for the HyspIRI mission, a small team was assembled to determine the optimum saturation level for the mid-infrared (4-?m) channel, which is dedicated to the measurement of hot targets. Examples of hot targets include wildland fires and active lava flows. This determination took into account both the temperature expected for the natural phenomena and the expected performance of the mid-infrared channel as well as its overlap with the other channels in the thermal infrared (7.5-12 ?m) designed to measure the temperature of lower temperature targets. Based on this work, the hot target saturation group recommends a saturation temperature of 1200 K for the mid-infrared channel. The saturation temperature of 1200 K represents a good compromise between the prevention of saturation and sensitivity to ambient temperature
Soil bulk density sampling for neutron gauge calibration
The ASCE Task Committee on Neutron Gauge Calibration met in Logan, Utah in July
1992 to investigate the various methods of soil sampling, installation of access tubes,
effect of various parameters on gauge readings, methods of developing field calibration
curves and comparison of neutron gauge characteristics. Details of the overall objectives
of the study are covered by Stone (1993, this volume). This paper discusses the soil
sampling methods and presents a comparative result based on bulk density, time required
for sampling and cost of sampling equipment Other papers developed from this study
describe the soils, the three sites investigated and the problems related to the tube
installation process
Neutron gauge calibration comparison of methods
Several methods for obtaining soil samples for determining soil water content were used
for field calibration of neutron gauges. This paper compares the results of calibration
curves obtained from the study data by comparing intercepts, slopes and correlation
coefficients ("r" values). The study found differences in characteristics between gauges
of the same brand, differences between brands and a great effect by access tube
materials on the calibration curve
The ASCE neutron probe calibration study: overview
A workshop was held at Logan, Utah to gather field information on
neutron probe calibration and operation. Several techniques and instruments
were compared. This paper serves to establish the background information for
the work and describe the overall approaches, conditions, and equipment. Other
papers presented at this conference provide detailed procedures and results
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