Gliding performance in the yellow-bellied glider in low-canopy forest

2014 ◽  
Vol 36 (2) ◽  
pp. 254 ◽  
Author(s):  
Ross L. Goldingay
Keyword(s):  
Habitat Connectivity ◽  
Horizontal Distance ◽  
Horizontal Branch ◽  
Main Trunk ◽  
Open Forest ◽  
The Mean ◽  
Western Victoria ◽  
Petaurus Australis

Knowledge of the gliding performance of gliding mammals is fundamental to understanding how these species have adapted to their environment and is of increasing relevance to their conservation. I describe aspects of the glide performance of the yellow-bellied glider (Petaurus australis) based on 22 glides of 17 individuals within 20–30-m-high open forest in western Victoria. Gliders launched into a glide from a horizontal branch that was, on average, 2.8 m below the top of a tree, 5.2 m out from the main trunk and 18.5 m above the ground. Gliders landed on the trunks of trees 5.8 m above the ground. The mean horizontal glide distance was 25.2 ± 1.5 m (s.e.) (range = 19–45 m), producing a glide ratio (horizontal distance/height dropped) of 2.0 and a glide angle of 27.3°. These values are similar to those reported for other gliding petaurids in low-canopy forest. This knowledge should be used to guide the management of habitat connectivity for yellow-bellied gliders.

scholarly journals Whistler intensities above thunderstorms

2010 ◽  
Vol 28 (1) ◽  
pp. 37-46 ◽  
Author(s):  
J. Fiser ◽  
J. Chum ◽  
G. Diendorfer ◽  
M. Parrot ◽  
O. Santolik
Keyword(s):  
Background Noise ◽  
Electromagnetic Waves ◽  
Horizontal Distance ◽  
Average Amplitude ◽  
Oblique Propagation ◽  
Lightning Current ◽  
Processing Data ◽  
Demeter Satellite ◽  
Late Evening ◽  
The Mean

Abstract. We report a study of penetration of the VLF electromagnetic waves induced by lightning to the ionosphere. We compare the fractional hop whistlers recorded by the ICE experiment onboard the DEMETER satellite with lightning detected by the EUCLID detection network. To identify the fractional hop whistlers, we have developed software for automatic detection of the fractional-hop whistlers in the VLF spectrograms. This software provides the detection times of the fractional hop whistlers and the average amplitudes of these whistlers. Matching the lightning and whistler data, we find the pairs of causative lightning and corresponding whistler. Processing data from ~200 DEMETER passes over the European region we obtain a map of mean amplitudes of whistler electric field as a function of latitudinal and longitudinal difference between the location of the causative lightning and satellite magnetic footprint. We find that mean whistler amplitude monotonically decreases with horizontal distance up to ~1000 km from the lightning source. At larger distances, the mean whistler amplitude usually merges into the background noise and the whistlers become undetectable. The maximum of whistler intensities is shifted from the satellite magnetic footprint ~1° owing to the oblique propagation. The average amplitude of whistlers increases with the lightning current. At nighttime (late evening), the average amplitude of whistlers is about three times higher than during the daytime (late morning) for the same lightning current.

scholarly journals Influence of spatial heterogeneity of local surface albedo on the area-averaged surface albedo retrieved from airborne irradiance measurements

2013 ◽  
Vol 6 (3) ◽  
pp. 527-537 ◽  
Author(s):  
E. Jäkel ◽  
M. Wendisch ◽  
B. Mayer
Keyword(s):  
Optical Depth ◽  
Surface Albedo ◽  
Radiative Transfer Model ◽  
Small Scale ◽  
Mean Deviation ◽  
Transfer Model ◽  
Horizontal Distance ◽  
Local Surface ◽  
Atmospheric Scattering ◽  
The Mean

Abstract. Spectral airborne upward and downward irradiance measurements are used to derive the area-averaged surface albedo. Real surfaces are not homogeneous in their reflectivity. Therefore, this work studies the effects of the heterogeneity of surface reflectivity on the area-averaged surface albedo to quantify how well aircraft measurements can resolve the small-scale variability of the local surface albedo. For that purpose spatially heterogeneous surface albedo maps were input into a 3-dimensional (3-D) Monte Carlo radiative transfer model to simulate 3-D irradiance fields. The calculated up- and downward irradiances in altitudes between 0.1 and 5 km are used to derive the area-averaged surface albedo using an iterative retrieval method that removes the effects due to atmospheric scattering and absorption within the layer beneath the considered level. For the case of adjacent land and sea surfaces, parametrizations are presented which quantify the horizontal distance from the coastline that is required to reduce surface heterogeneity effects on the area-averaged surface albedo to a given limit. The parametrization which is a function of altitude, aerosol optical depth, single scattering albedo, and the ratio of local land and sea albedo was applied for airborne spectral measurements. In addition, the deviation between area-averaged and local surface albedo is determined for more complex surface albedo maps. For moderate aerosol conditions (optical depth less than 0.4) and a wavelength range between 400 and 1000 nm, the altitude and the heterogeneity of the surface albedo are the dominant factors determining the mean deviation between local and area-averaged surface albedo. A parametrization of the mean deviation is applied to an albedo map that was derived from a Landsat image of an area in East Anglia (UK). Parametrization and direct comparison of local and area-averaged surface albedo show similar mean deviations (20% vs. 25%) over land.

Shelter selection by a small mammal community in the wet-dry tropics of Australia.

1989 ◽  
Vol 12 (2) ◽  
pp. 55
Author(s):  
R.W. Braithwaite
Keyword(s):  
Habitat Selection ◽  
Small Mammal ◽  
Tree Species ◽  
Average Distance ◽  
Small Species ◽  
Dry Tropics ◽  
Open Forest ◽  
Shelter Selection ◽  
Small Mammal Community ◽  
The Mean

The location of shelter used by nine species of small mammals released after capture during a mark-recapture study in tropical woodland and open forest was recorded whenever possible. A quantitative profile of such post-release behaviour by different species permits its incorporation into analyses of habitat selection. Characteristics of post-release behaviour also provide clues about the nature of predation pressure on various species. Arboreal species tended to select tree species with boles having camouflage potential. Small species used small holes. Scansorial species used the greatest range of sheltering sites. Average distance moved to shelter was inversely related to the mean density of a species.

Effects of variation in liveweight at birth and weaning on subsequent reproductive rate in sheep

1969 ◽  
Vol 9 (39) ◽  
pp. 381
Author(s):  
PD Mullaney
Keyword(s):  
Reproductive Performance ◽  
Live Weight ◽  
Reproductive Rate ◽  
The Mean ◽  
Western Victoria ◽  
First Time

Observations were carried out on one Polwarth, three Corriedale, and four Merino flocks in Western Victoria to investigate the influence of a ewe's own live weight at birth and weaning on her subsequent reproductive performance, when lambing for the first time. Weaning weights were adjusted to 140 days of age. The mean adjusted weaning weights were 26-35 lb (Merino), 27-48 lb (Corriedale), and 37 lb (Polwarth). Variation in the live weight of ewes at birth had little or no effect on either the number of lambs born per ewe joined (LBJ) or the number of lambs weaned per ewe joined (LW]), when the ewes lambed for the first time at either two or three years old. Variation in the live weight of ewes at weaning generally had only a small effect on both LBJ and LWJ at first lambing. On three properties, there was, however, an increase of about 3 per cent in LBJ and about 2 per cent in LWJ for each 10 lb increase in the ewe's own live weight at weaning.

Movements and cumulative range size of the platypus (Ornithorhynchus anatinus) inferred from mark–recapture studies

2012 ◽  
Vol 60 (5) ◽  
pp. 352 ◽  
Author(s):  
M. Serena ◽  
G. A. Williams
Keyword(s):  
Range Size ◽  
River Catchment ◽  
Young Males ◽  
Adult Females ◽  
Ornithorhynchus Anatinus ◽  
Males And Females ◽  
The Mean ◽  
Western Victoria ◽  
Fyke Nets ◽  
Age And Sex

The extent of mammalian movements often varies with size, sex and/or reproductive status. Fyke nets were set along streams and rivers near Melbourne (southern Victoria) from the mid-1990s to 2007, and in the Wimmera River catchment (western Victoria) from 1997 to 2005, to assess how far platypus of different age and sex classes travelled between captures and over longer periods. The mean distance between consecutive captures of adults did not vary significantly as intervals increased from 1–3 months to >3 years, suggesting that most individuals occupied stable ranges. However, adult females travelled, on average, only 35% as far between captures as males in southern Victoria, and 29% as far in the Wimmera. Up to half of this difference may be explained by variation in size-related metabolic requirements. Immature males and females respectively moved 61% and 53% as far, on average, as their adult equivalents, although two young males dispersed >40 km. Adults incrementally occupied up to 13.9 km of channel in the case of a male (based on six captures over 67 months) and 4.4 km of channel in the case of a female (based on five captures over 127 months).

Pronator Teres Branch Transfer to the Anterior Interosseous Nerve for Treating C8T1 Brachial Plexus Avulsion

Neurosurgery ◽  
2014 ◽  
Vol 75 (4) ◽  
pp. 375-379 ◽  
Author(s):  
Jianyun Yang ◽  
Xiaotian Jia ◽  
Cong Yu ◽  
YuDong Gu
Keyword(s):  
Range Of Motion ◽  
Lateral Condyle ◽  
Main Trunk ◽  
Medial Condyle ◽  
Pronator Teres ◽  
Finger Flexion ◽  
Active Range Of Motion ◽  
Anterior Interosseous Nerve ◽  
The Mean ◽  
Finger Flexor Muscles

Abstract BACKGROUND: The treatment of C8T1 avulsion is challenging for neurosurgeons. Various methods for the restoration of finger flexion are used. However, most of these methods have different disadvantages and cannot restore the full active range of motion of the fingers. OBJECTIVE: To determine the feasibility of the pronator teres branch transfer to the anterior interosseous nerve with anatomic study and to use this method in 1 case. METHODS: The upper limbs of 15 fresh cadavers were dissected to identify the main trunk of the median nerve, the pronator teres branch, and the anterior interosseous nerve. The mean number and length of the pronator teres branches were recorded. The anterior interosseous nerve was dissected atraumatically to the most proximal level where the fibers of the anterior interosseous nerve did not mingle with the fibers of the main trunk of the median, which was defined as the atraumatic level of the anterior interosseous nerve. A line joining the most protruding point of the medial condyle and lateral condyle of the humerus was used as a measurement landmark. Pronator teres branch transfer to the anterior interosseous nerve was performed in 1 patient with C8T1 avulsion. RESULTS: The mean number of the pronator teres branches was 2.37 ± 0.49. The mean length of the pronator teres branches was 9.64 ± 0.71 mm. The mean distance between the point where the pronator teres branches originated and the landmark line was 3.87 ± 0.34 mm. The mean distance between the atraumatic level of the anterior interosseous nerve and the landmark line was −5.46 ± 0.73 mm. Transfer of the pronator teres was used to innervate the anterior interosseous nerve in 1 patient with C8T1 avulsion. When assessed 14 months after the operation, a full active range of motion of the fingers had been restored, and the patient's finger flexor muscles had regained grade 4 power. CONCLUSION: The pronator teres can be transferred to the anterior interosseous nerve directly at the elbow level. This operation was performed successfully in 1 patient, who exhibited finger flexion recovery.

Use of stream and river habitats by the platypus, Ornithorhynchus anatinus, in an urban fringe environment

1998 ◽  
Vol 46 (3) ◽  
pp. 267 ◽  
Author(s):  
M. Serena ◽  
J. L. Thomas ◽  
G. A. Williams ◽  
R. C. E. Officer
Keyword(s):  
Radio Telemetry ◽  
Central Business District ◽  
Home Ranges ◽  
Horizontal Distance ◽  
North East ◽  
Ornithorhynchus Anatinus ◽  
Drainage Channels ◽  
The Mean ◽  
Business District ◽  
Yarra River

Radio-telemetry was used to monitor movements and burrow usage by O. anatinus living in the Yarra River catchment, about 20 km east-north-east of the central business district of Melbourne, Victoria. The home ranges of six adult or subadult animals were 2.9–7.3 km (mean ± s.d. = 4.6 ± 1.6 km) long, with individuals travelling up to 10.4 km (males) and 4.0 km (females) in a single overnight period. The mean home-range length of adult/subadult animals was significantly greater than that of juveniles (1.4–1.7 km, mean ± s.d. = 1.55 ± 0.2 km, n = 2). The animals utilised two drainage channels as well as 11.8 km of natural waterways, including the Yarra River (5 km), Mullum Mullum Creek (4 km) and Diamond Creek (2.8 km). Several animals travelled repeatedly below one-lane and two-lane bridges, confirming that these structures are not inherent barriers to platypus movement. In total, 57 platypus burrows were described, including 26 along the river, 29 along the creeks and 2 along drains. The horizontal distance from the water’s edge to burrow chambers was 0.4–3.7 m (mean ± s.d. = 1.5 ± 0.9 m, n = 41), with burrows found only in banks extending ≥ 0.5 m above the water. Platypus burrows occurred significantly more often than expected along undercut banks and in association with moderate-to-dense vegetation overhanging the water, and significantly less often at sites where banks had a convex profile at water level. As well, the amount of cover provided along the bank by shrubs/small trees and the ground layer of vegetation was significantly greater than expected at platypus burrows along the river. These attributes are believed to help conceal burrow entrances from predators as well as reduce burrow damage through erosion.

Global radiation within subarctic open forest canopies

1994 ◽  
Vol 24 (5) ◽  
pp. 1062-1066 ◽  
Author(s):  
Peter M. Lafleur ◽  
Blair K. Mantha
Keyword(s):  
Solar Radiation ◽  
Global Radiation ◽  
Tree Height ◽  
Global Solar Radiation ◽  
Canopy Closure ◽  
Predictive Equations ◽  
Forest Canopies ◽  
Open Forest ◽  
Linear Relationships ◽  
The Mean

Measurements of global solar radiation were made at six sites with varying architecture within a subarctic open forest near Churchill, Manitoba. Below-canopy radiation was determined from a network of nine sensors and the mean was compared with global radiation above the canopy. The ratio of below- to above-canopy radiation, R, ranged from 0.52 to 0.7 for the six sites. This range falls within the range of observations from other subarctic sites. At all sites, R was smaller for clear than for overcast skies; however, the differences were not statistically significant. The data from this study were combined with data from the literature in order to develop predictive equations for solar radiation at the floor of subarctic forests, based on easily derived forest parameters. Linear relationships were found between R and canopy closure (r2 = 0.76) and between R and tree height (r2 = 0.88).

scholarly journals Influence of spatial heterogeneity of local surface albedo on the area-averaged surface albedo retrieved from airborne irradiance measurements

2012 ◽  
Vol 5 (5) ◽  
pp. 7457-7487
Author(s):  
E. Jäkel ◽  
M. Wendisch ◽  
B. Mayer
Keyword(s):  
Optical Depth ◽  
Surface Albedo ◽  
Radiative Transfer Model ◽  
Small Scale ◽  
Mean Deviation ◽  
Transfer Model ◽  
Horizontal Distance ◽  
Local Surface ◽  
Atmospheric Scattering ◽  
The Mean

Abstract. Spectral airborne upward and downward irradiance measurements are used to derive the area-averaged surface albedo. Real surfaces are not homogeneous in their reflectivity. Therefore, this work studies the effects of the heterogeneity of surface reflectivity on the area-averaged surface albedo to quantify how well aircraft measurements can resolve the small-scale variability of the local surface albedo. For that purpose spatially heterogeneous surface albedo maps were input into a 3-dimensional (3-D) Monte Carlo radiative transfer model to simulate 3-D irradiance fields. The calculated up- and downward irradiances in altitudes between 0.1 km and 5 km are used to derive the area-averaged surface albedo using an iterative retrieval method that removes the effects due to atmospheric scattering and absorption within the layer beneath the considered level. For the case of adjacent land and sea surfaces a parametrization is presented which quantifies the horizontal distance to the coastline that is required to reduce surface heterogeneity effects on the area-averaged surface albedo to a given limit. The parametrization which is a function of altitude, aerosol optical depth, and the ratio of local land and sea albedo was applied for airborne spectral measurements. In addition, the deviation between area-averaged and local surface albedo is determined for more complex surface albedo maps. For moderate aerosol conditions (optical depth less than 0.4) and the visible wavelength range, the altitude and the heterogeneity of the surface albedo are the dominant factors determining the mean deviation between local and area-averaged surface albedo. A parametrization of the mean deviation is applied to an albedo map that was derived from a Landsat image of an area in East Anglia (UK). Parametrization and direct comparison of local and area-averaged surface albedo show similar mean deviations (20% vs. 25%) over land.

Effect of synthetic windbreaks on pasture growth in south-western Victoria, Australia

2002 ◽  
Vol 42 (6) ◽  
pp. 831 ◽  
Author(s):  
P. R. Bird ◽  
T. T. Jackson ◽  
K. W. Williams
Keyword(s):  
Field Experiments ◽  
Temperate Zone ◽  
Wire Mesh ◽  
Seasonal Effect ◽  
Total Production ◽  
Maximum Difference ◽  
Cool Temperate ◽  
The Mean ◽  
Western Victoria ◽  
The Impact

The impact of a synthetic windbreak on the growth of subterranean clover and perennial ryegrass pasture in the cool-temperate zone of south-western Victoria was investigated over 2 years. Four square plots (10 m sides) at each of 2 sites were fenced with wire mesh 1.2 m tall in 1996 and 1997. Two plots at each site were sheltered with synthetic mesh of 50% porosity attached to the wire mesh. The open wind speed averaged 3.6 m/s in 1996 and 3.1�m/s in 1997. Winds exceeded 6 m/s for 4–23% and 2–8% of the time in 1996 and 1997, respectively. There were small but significant differences in temperature between the sheltered and open plots. The mean daily temperature was 0–0.4°C warmer with shelter. Temperatures in the shelters were always higher from 0900 to 1800�hours, the differences ranging from 0.1 to 0.9°C. Conversely, lower temperatures (a maximum difference of 0.4°C) usually occurred in the shelters from 1800 to 0600 hours. The mean daily relative humidity was 1.4–3.1% greater in shelter than in the open and the maximum difference was 3.8%. There was a significant (P< 0.01) effect of shelter on pasture growth in both years. In terms of total production over both years, the results indicate a small but consistent increase in pasture growth of about 9% for sheltered v. open plots at both sites. There was a clear seasonal effect of shelter, with greater production in autumn–winter, and a trend towards greater production in open plots during very wet periods. The results indicate that responses of pasture plants to shelter in the cool-temperate zone of Australia may be modest, and difficult to determine in field experiments, but shelter should contribute significantly to animal production because of improved plant growth in times of scarcity and reduced expenditure of energy for maintenance. Artificial shelters may provide the best means of testing the likely response to shelter of other pasture species or crops.

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