scholarly journals An assessment of the accuracy of kangaroo surveys using fixed-wing aircraft

1998 ◽  
Vol 25 (3) ◽  
pp. 315 ◽  
Author(s):  
A. R. Pople ◽  
S. C. Cairns ◽  
T. F. Clancy ◽  
G. C. Grigg ◽  
L. A. Beard ◽  
...  
Keyword(s):  
Standard Form ◽  
Cost Effective ◽  
Line Transect ◽  
Attractive Alternative ◽  
Correction Factors ◽  
Density Estimates ◽  
Macropus Rufus ◽  
Transect Counts ◽  
Biased Estimates ◽  
Strip Transect

The use of line-transect methodology, on foot or from a helicopter, is likely to return the most repeatable, least biased estimates of kangaroo density. However, the associated costs make both methods impractical for broad-scale surveys. For these, a fixed-wing aircraft remains the most cost-effective platform. Limitations of the standard fixed-wing method (200-m strip transects) are well known, but it continues to be used because it provides an index of trends, because there are now long runs of data (almost 20 years in some cases) collected in this standard form and an alternative method is lacking. In this study, four variations of fixed-wing surveys of kangaroos were investigated: two line-transect methods (involving different scanning techniques), the standard 200-m strip transect and a 100-m strip transect. Surveys using these methods were compared with helicopter line-transect surveys along the same flight lines in three areas (5000–7500 km2) in western Queensland. Both fixed-wing line-transect methods failed to produce consistently accurate estimates of density for all three species surveyed: red kangaroos (Macropus rufus), eastern grey kangaroos (M. giganteus) and common wallaroos (M. robustus). While generally more accurate than the uncorrected strip-transect counts, they were no less variable. However, the strip-transect counts still need to be corrected for bias for which this study offers revised estimates of correction factors for eastern grey kangaroos (3.7–10.2) and common wallaroos (3.8–4.1), and estimates for red kangaroos (1.7–2.7) that support currently used values. An attractive alternative is to survey in 100-m strip transects, which offer improved visibility (correction factors of 1.0–1.8 for red kangaroos, 2.1–3.6 for eastern grey kangaroos and 1.7–2.1 for common wallaroos) and are therefore likely to be more accurate and repeatable. However, these advantages need to be assessed in relation to continuing long runs of data using the standard 200-m strip transect. Correction factors for wallaroos are conservative as helicopter-based density estimates are known to be underestimates. Further work is needed to assess the generality of correction factors, both spatially and temporally.

scholarly journals Comparison of Surveys of Kangaroos in Queensland Using Helicopters and Fixed-Wing Aircraft.

1998 ◽  
Vol 20 (1) ◽  
pp. 92 ◽  
Author(s):  
AR Pople ◽  
SC Cairns ◽  
TF Clancy ◽  
GC Grigg ◽  
LA Beard ◽  
...  
Keyword(s):  
Aerial Survey ◽  
Population Estimates ◽  
Line Transect ◽  
Correction Factors ◽  
Density Estimates ◽  
Australian State ◽  
Transect Counts ◽  
Comparative Accuracy ◽  
Harvest Quotas ◽  
Strip Transect

Kangaroo harvest quotas for each Australian state have been set mainly as proportions of population estimates derived from aerial surveys. Estimating population size from strip transect counts using fixed- wing aircraft has become an established technique, but counts must be adjusted by correction factors to ensure population estimates are both accurate and repeatable. Surveys of kangaroos in Queensland are currently conducted with helicopters using line transect methodology, but cost restricts their use to relatively small survey blocks. Nevertheless, they return more accurate and repeatable estimates of kangaroo density than surveys with fixed-wing aircraft. A comparison of the above two techniques was made along the same transect lines in seven survey blocks (5000-10,000 km2) in southern and western Queensland, allowing an assessment of the comparative accuracy of the fixed-wing method. For red kangaroos (Macropus rufus), required correction factors of 0.7-3.1 were similar to those used previously. However, for eastern grey kangaroos (M. giganteus), substantially larger correction factors of 3.4-10.2 were needed to approach true density. For wallaroos (M. robustus), correction factors of 3.8-4.8 were required, but can be considered conservative because helicopter-derived density estimates are known to be underestimated by a factor of 2-3. Further work is needed to establish how correction factors for each species should be applied on a broader scale and whether they lead to repeatable estimates of kangaroo density. Key words: aerial survey, line transect, correction factors, strip transect, wallaroo.

An Evaluation of the Strip Transect Method for Censusing Bird Communities in Forests

1986 ◽  
Vol 13 (2) ◽  
pp. 203 ◽  
Author(s):  
RH Harden ◽  
RJ Muir ◽  
DR Milledge
Keyword(s):  
New South ◽  
Bird Communities ◽  
Density Estimate ◽  
Density Estimates ◽  
Number Of Species ◽  
South Wales ◽  
Sclerophyll Forest ◽  
Transect Counts ◽  
Estimate Number ◽  
Strip Transect

The effects of varying transect width and census duration on the number of birds counted, the density estimate, number of species detected and the percentage of unidentified birds were examined in rainforest and wet sclerophyll forest at Mount Nardi in northern New South Wales. The nine combinations of three strip widths (40, 60 and 80 m) and three durations of census (24, 18 and 12 min) were compared in 200-m-long transects in each forest. The census of birds was more sensitive to changes in census duration than in strip width, and the effects were greater in the rainforest than the wet sclerophyll forest. Both the precision of the density estimates and the number of species detected were highest for the narrowest strips censused for the longest time. The bias of the density estimate varied with the treatments both within and between forests, and thus the strip transect could not be used to compare them. We suggest that variation in bias between sites may be a problem common to all transect counts of birds.

Comparison of Helicopter Line Transects with Walked Line Transects for Estimating Densities of Kangaroos

1997 ◽  
Vol 24 (4) ◽  
pp. 397 ◽  
Author(s):  
T. F. Clancy ◽  
A. R. Pople ◽  
L. A. Gibson
Keyword(s):  
Repeated Measures ◽  
Aerial Survey ◽  
Survey Method ◽  
Line Transect ◽  
Attractive Alternative ◽  
Line Transect Sampling ◽  
Density Estimates ◽  
Transect Sampling ◽  
Grey Kangaroo ◽  
Line Transects

The performance of helicopter surveys for estimating population densities of red kangaroos (Macropus rufus), eastern grey kangaroos (Macropus giganteus) and common wallaroos (Macropus robustus) was investigated by comparing line-transect density estimates obtained from helicopter surveys with those from ground (walked) surveys. Comparisons were made at four sites in central western Queensland (areas with high densities of red kangaroos and common wallaroos) that were surveyed during winter and summer from December 1991 until February 1995, and one site in south-eastern Queensland (an area of high eastern grey kangaroo density) surveyed annually during autumn from March 1991 until March 1994. Helicopter surveys generally recorded lower sample sizes than did ground surveys (means ± s.e = 34 ± 6%, 33 ± 9% and 76 ± 2% lower for red kangaroos, eastern grey kangaroos and wallaroos, respectively). Density estimates obtained from the helicopter surveys were not significantly different from those obtained from ground surveys for both red and eastern grey kangaroos as assessed by repeated-measures ANOVA and regression analysis. However, helicopter surveys of common wallaroos consistently returned density estimates about half those of ground surveys. The relationships between the two methods did not differ between winter and summer for any species. The conventional aerial survey method for kangaroos of strip transects from fixed-wing aircraft has limited ability to adjust for varying sightability conditions. Therefore, helicopter surveys with line-transect sampling are an attractive alternative.

scholarly journals Fencing artificial waterpoints failed to influence density and distribution of red kangaroos (Macropus rufus)

2009 ◽  
Vol 36 (6) ◽  
pp. 457 ◽  
Author(s):  
Y. Fukuda ◽  
H. I. McCallum ◽  
G. C. Grigg ◽  
A. R. Pople
Keyword(s):  
Protected Areas ◽  
Food Availability ◽  
National Park ◽  
Water Sources ◽  
Spatial Context ◽  
Line Transect ◽  
Macropus Rufus ◽  
Pellet Counts ◽  
Transect Counts ◽  
Vegetation Regeneration

Provision of artificial waterpoints in Australian rangelands has resulted in an increase in the range and density of kangaroos. At high densities, kangaroos can inhibit vegetation regeneration, particularly in some protected areas where harvesting is prohibited. Fencing off waterpoints has been proposed to limit these impacts. Our aim was to determine whether fencing off waterpoints during a drought (when kangaroos would be especially water-limited) would influence the density and distribution of red kangaroos (Macropus rufus). Two waterpoints were fenced within the first 6 months of the 27-month study and a further two waterpoints were kept unfenced as controls in Idalia National Park, western Queensland. We estimated kangaroo densities around waterpoints from walked line-transect counts, and their grazing distribution from dung-pellet counts. Fencing off waterpoints failed to influence either the density or distribution up to 4 km from the waterpoints. Our results indicate that food availability, rather than the location of waterpoints, determines kangaroo distribution. Few areas in the rangelands are beyond kangaroos’ convenient reach from permanent waterpoints. Therefore, fencing off waterpoints without explicitly considering the spatial context in relation to other available water sources will fail to achieve vegetation regeneration.

scholarly journals Evaluation of counting methods for monitoring populations of a cryptic alpine passerine, the rock wren (Passeriformes, Acanthisittidae, Xenicus gilviventris)

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247873
Author(s):  
Joanne M. Monks ◽  
Colin F. J. O’Donnell ◽  
Terry C. Greene ◽  
Kerry A. Weston
Keyword(s):  
Low Cost ◽  
Distance Sampling ◽  
Cost Effective ◽  
Line Transect ◽  
Cost Effective Method ◽  
Mammalian Predators ◽  
Transect Counts ◽  
Line Transects ◽  
Population Indices ◽  
Species Specific

Developing and validating methods to determine trends in populations of threatened species is essential for evaluating the effectiveness of conservation interventions. For cryptic species inhabiting remote environments, this can be particularly challenging. Rock wrens, Xenicus gilviventris, are small passerines endemic to the alpine zone of southern New Zealand. They are highly vulnerable to predation by introduced mammalian predators. Establishing a robust, cost-effective monitoring tool to evaluate population trends in rock wrens is a priority for conservation of both the species and, more broadly, as part of a suite of indicators for evaluating effectiveness of management in New Zealand’s alpine ecosystems. We assessed the relative accuracy and precision of three population estimation techniques (mark-resight, distance sampling and simple counts on line transects) for two populations of rock wrens in the Southern Alps over six breeding seasons (2012–2018). The performance of these population estimators was compared to known rock wren population size derived from simultaneous territory mapping. Indices of abundance derived from counts on transects were correlated with territory mapping at both study areas, and performed better than either mark-resight methods or distance sampling. Simple counts on standardised line transects are a highly cost-effective method of monitoring birds because they do not require banding a population. As such, we recommend that line transect counts using the design outlined in this paper be adopted as a standard method for long-term monitoring of rock wren populations. Although species-specific testing is required to validate use of low-cost population indices, our results may have utility for the monitoring of other cryptic passerines in relatively open habitats.

scholarly journals Microsphere-Based Microfluidic Device for Plasma Separation and Potential Biochemistry Analysis Applications

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 487
Author(s):  
Hongyan Xu ◽  
Zhangying Wu ◽  
Jinan Deng ◽  
Jun Qiu ◽  
Ning Hu ◽  
...  
Keyword(s):  
Blood Sample ◽  
Microfluidic Device ◽  
Biochemical Analysis ◽  
Cost Effective ◽  
Clinical Diagnostics ◽  
Correction Factors ◽  
Separation Device ◽  
Blood Samples ◽  
Plasma Separation ◽  
Blood Biochemical

The development of a simple, portable, and cost-effective plasma separation platform for blood biochemical analysis is of great interest in clinical diagnostics. We represent a plasma separation microfluidic device using microspheres with different sizes as the separation barrier. This plasma separation device, with 18 capillary microchannels, can extract about 3 μL of plasma from a 50 μL blood sample in about 55 min. The effects of evaporation and the microsphere barrier on the plasma biochemical analysis results were studied. Correction factors were applied to compensate for these two effects. The feasibility of the device in plasma biochemical analysis was validated with clinical blood samples.

Pilot plant study on the performance and optimization of submerged membranes for taste and odor removal

2002 ◽  
Vol 2 (2) ◽  
pp. 185-192 ◽  
Author(s):  
L. Schideman ◽  
V.L. Snoeyink ◽  
B.J. Mariñas ◽  
M. Kosterman
Keyword(s):  
Lake Michigan ◽  
System Modeling ◽  
Cost Effective ◽  
Membrane System ◽  
Pilot Scale ◽  
Attractive Alternative ◽  
Beneficial Effects ◽  
Ideal Mixing ◽  
Taste And Odor ◽  
Cake Layer

Hybrid sorption-membrane processes are an attractive alternative for meeting a range of water treatment goals in a single process that is compact and cost-effective. This study investigated the performance and optimization of a hybrid sorption-membrane process using powdered activated carbon (PAC) and submerged-style membranes for odor control. Specifically, this study focused on the removal of 2-methylisoborneol (2-MIB) from a Lake Michigan source water and investigated the effects of PAC dose, dosing method, backwash interval, and aeration. Adsorption performance was predicted using a mathematical model, and tested using a pilot-scale, submerged membrane system. Modeling continuously dosed PAC performance agreed well with pilot results, but pulse dosed PAC performance was overestimated by the model. Non-ideal mixing effects were identified as important factors in explaining the pulse dosing results. Pilot results with aeration and pulse dosing were also overestimated by the model. It is hypothesized that aeration disturbs the PAC cake layer that forms on the membrane, and thus eliminates the beneficial effects that this cake layer can have on adsorption. Extending backwash intervals from 30 to 180 minutes with continuous dosing increased the percent removal of 2-MIB by up to 30% in both the model predictions and pilot results. This study highlights some important considerations in the design of full-scale systems and future mathematical models.

scholarly journals Usability Evaluation of Encyclopedia Websites

2021 ◽  
Vol 11 (1) ◽  
pp. 21-25
Author(s):  
Nor Azman Ismail ◽  
Fadzrul Izwan Jamaluddin ◽  
Akmal Harraz Hamidan ◽  
Ahmad Fariz Ali ◽  
Su Elya Mohamed ◽  
...  
Keyword(s):  
Standard Form ◽  
Usability Testing ◽  
Cost Effective ◽  
Usability Evaluation ◽  
Web Performance ◽  
Testing Tools ◽  
Usability Tests ◽  
Website Analysis ◽  
User Friendly

Usability is an important aspect that every website should focus more. It tells us how well and success website will function with real users. Many people often think usability tests are expensive and time-consuming. It can be a cost-effective and time saver with usability testing instead of spending more time fixing an unusable website. This study evaluates the usability of encyclopedia websites by using automated usability testing tools and questionnaire methods. The questionnaire was developed based on a standard form called Website Analysis and Measurement Inventory (WAMMI) that identified 20 common usability questions divided into five categories. Each category deals with one aspect of usability. Simultaneously, the automated usability testing tools used in this study were Pingdom and GT Metrix to calculate and analyse the website performance of selected encyclopedia websites based on website components including page load time, media size and overall web performance grades. This study could help web designer, developer, and practitioners design better and more user-friendly encyclopedia websites.

scholarly journals Investigating CXCR4 expression of tumor cells and the vascular compartment: A multimodal approach

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260186
Author(s):  
Marta Braga ◽  
Chee Hau Leow ◽  
Javier Hernandez Gil ◽  
Jin H. Teh ◽  
Laurence Carroll ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Microvessel Density ◽  
Ex Vivo ◽  
Cost Effective ◽  
Cxcr4 Expression ◽  
Attractive Alternative ◽  
Tumor Models ◽  
Chemokine Receptor 4 ◽  
And Control ◽  
Vascular Compartment

The C-X-C chemokine receptor 4 (CXCR4) is G protein-coupled receptor that upon binding to its cognate ligand, can lead to tumor progression. Several CXCR4-targeted therapies are currently under investigation, and with it comes the need for imaging agents capable of accurate depiction of CXCR4 for therapeutic stratification and monitoring. PET agents enjoy the most success, but more cost-effective and radiation-free approaches such as ultrasound (US) imaging could represent an attractive alternative. In this work, we developed a targeted microbubble (MB) for imaging of vascular CXCR4 expression in cancer. A CXCR4-targeted MB was developed through incorporation of the T140 peptide into the MB shell. Binding properties of the T140-MB and control, non-targeted MB (NT-MB) were evaluated in MDA-MB-231 cells where CXCR4 expression was knocked-down (via shRNA) through optical imaging, and in the lymphoma tumor models U2932 and SuDHL8 (high and low CXCR4 expression, respectively) by US imaging. PET imaging of [18F]MCFB, a tumor-penetrating CXCR4-targeted small molecule, was used to provide whole-tumor CXCR4 readouts. CXCR4 expression and microvessel density were performed by immunohistochemistry analysis and western blot. T140-MB were formed with similar properties to NT-MB and accumulated sensitively and specifically in cells according to their CXCR4 expression. In NOD SCID mice, T140-MB persisted longer in tumors than NT-MB, indicative of target interaction, but showed no difference between U2932 and SuDHL8. In contrast, PET imaging with [18F]MCFB showed a marked difference in tumor uptake at 40–60 min post-injection between the two tumor models (p<0.05). Ex vivo analysis revealed that the large differences in CXCR4 expression between the two models are not reflected in the vascular compartment, where the MB are restricted; in fact, microvessel density and CXCR4 expression in the vasculature was comparable between U2932 and SuDHL8 tumors. In conclusion, we successfully developed a T140-MB that can be used for imaging CXCR4 expression in the tumor vasculature.

scholarly journals Biomass Valorization to Produce Porous Carbons: Applications in CO2 Capture and Biogas Upgrading to Biomethane—A Mini-Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Maria Bernardo ◽  
Nuno Lapa ◽  
Isabel Fonseca ◽  
Isabel A. A. C. Esteves
Keyword(s):  
Circular Economy ◽  
Gas Adsorption ◽  
Activated Carbons ◽  
Textural Properties ◽  
Cost Effective ◽  
Attractive Alternative ◽  
Porous Carbons ◽  
Environmentally Sustainable ◽  
Gas Phases ◽  
Metal Organic

Porous carbon materials, derived from biomass wastes and/or as by-products, are considered versatile, economical and environmentally sustainable. Recently, their high adsorption capacity has led to an increased interest in several environmental applications related to separation/purification both in liquid- and gas-phases. Specifically, their use in carbon dioxide (CO2) capture/sequestration has been a hot topic in the framework of gas adsorption applications. Cost effective biomass porous carbons with enhanced textural properties and high CO2 uptakes present themselves as attractive alternative adsorbents with potential to be used in CO2 capture/separation, apart from zeolites, commercial activated carbons and metal-organic frameworks (MOFs). The renewable and sustainable character of the precursor of these bioadsorbents must be highlighted in the context of a circular-economy and emergent renewable energy market to reach the EU climate and energy goals. This mini-review summarizes the current understandings and discussions about the development of porous carbons derived from bio-wastes, focusing their application to capture CO2 and upgrade biogas to biomethane by adsorption-based processes. Biogas is composed by 55–65 v/v% of methane (CH4) mainly in 35–45 v/v% of CO2. The biogas upgraded to bio-CH4 (97%v/v) through an adsorption process yields after proper conditioning to high quality biomethane and replaces natural gas of fossil source. The circular-economy impact of bio-CH4 production is further enhanced by the use of biomass-derived porous carbons employed in the production process.

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