An evaluation of transect, plot and aerial survey techniques to monitor the spatial pattern and status of the bilby (Macrotis lagotis) in the Tanami Desert

2005 ◽  
Vol 32 (1) ◽  
pp. 43 ◽  
Author(s):  
Richard Southgate ◽  
Rachel Paltridge ◽  
Pip Masters ◽  
Theresa Nano
Keyword(s):  
Spatial Pattern ◽  
Relative Abundance ◽  
False Negative ◽  
Ground Truth ◽  
Aerial Survey ◽  
Northern Territory ◽  
Survey Techniques ◽  
Survey Technique ◽  
Central Australia ◽  
Tracking Surface

We evaluated three monitoring techniques to determine the spatial pattern and relative abundance of the bilby (Macrotis lagotis) in the Tanami Desert, Northern Territory. All the methods examined relied on the identification of animal sign (foot imprints or diggings) to indicate the presence of a species. With fixed transects, a 10-km prepared tracking surface was monitored regularly using an all-terrain vehicle. With random plots, an unprepared tracking surface within a 200 × 300 m area was searched on foot for sign of the species. A helicopter was used in an aerial survey to identify bilby diggings from an altitude of 15–20 m while travelling at a speed of 30–40 knots along a predefined transect. The results for each method were stratified in relation to latitude and substrate to facilitate comparison of the efficacy of each technique. The fixed transects returned the least number of bilby records for most effort. The aerial transect technique resulted in few (<4%) false negative records but a sizeable (42%) number of false positive records. It is suggested that the aerial survey technique combined with ground-truth survey plots would provide reliable information on the extent of occurrence and status of the bilby in the remote spinifex deserts of central Australia.

scholarly journals Modelling the distribution and relative abundance of feral camels in the Northern Territory using count data

2010 ◽  
Vol 32 (1) ◽  
pp. 21 ◽  
Author(s):  
S. R. McLeod ◽  
A. R. Pople
Keyword(s):  
Relative Abundance ◽  
Habitat Suitability ◽  
Additive Model ◽  
Aerial Survey ◽  
Northern Territory ◽  
Suitable Habitat ◽  
Habitat Association ◽  
Generalised Additive Model ◽  
Suitability Maps ◽  
Index Of Abundance

The objectives of this study were to predict the potential distribution, relative abundance and probability of habitat use by feral camels in southern Northern Territory. Aerial survey data were used to model habitat association. The characteristics of ‘used’ (where camels were observed) v. ‘unused’ (pseudo-absence) sites were compared. Habitat association and abundance were modelled using generalised additive model (GAM) methods. The models predicted habitat suitability and the relative abundance of camels in southern Northern Territory. The habitat suitability maps derived in the present study indicate that camels have suitable habitat in most areas of southern Northern Territory. The index of abundance model identified areas of relatively high camel abundance. Identifying preferred habitats and areas of high abundance can help focus control efforts.

Brain FDG PET for the Etiological Diagnosis of Clinically Uncertain Cognitive Impairment During Delirium in Remission

2020 ◽  
Vol 77 (4) ◽  
pp. 1609-1622
Author(s):  
Franziska Mathies ◽  
Catharina Lange ◽  
Anja Mäurer ◽  
Ivayla Apostolova ◽  
Susanne Klutmann ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Fdg Pet ◽  
False Negative ◽  
Ground Truth ◽  
Etiological Diagnosis ◽  
Geriatric Unit ◽  
Positron Emission ◽  
The Brain ◽  
Hospitalized Geriatric Patients

Background: Positron emission tomography (PET) of the brain with 2-[F-18]-fluoro-2-deoxy-D-glucose (FDG) is widely used for the etiological diagnosis of clinically uncertain cognitive impairment (CUCI). Acute full-blown delirium can cause reversible alterations of FDG uptake that mimic neurodegenerative disease. Objective: This study tested whether delirium in remission affects the performance of FDG PET for differentiation between neurodegenerative and non-neurodegenerative etiology of CUCI. Methods: The study included 88 patients (82.0±5.7 y) with newly detected CUCI during hospitalization in a geriatric unit. Twenty-seven (31%) of the patients were diagnosed with delirium during their current hospital stay, which, however, at time of enrollment was in remission so that delirium was not considered the primary cause of the CUCI. Cases were categorized as neurodegenerative or non-neurodegenerative etiology based on visual inspection of FDG PET. The diagnosis at clinical follow-up after ≥12 months served as ground truth to evaluate the diagnostic performance of FDG PET. Results: FDG PET was categorized as neurodegenerative in 51 (58%) of the patients. Follow-up after 16±3 months was obtained in 68 (77%) of the patients. The clinical follow-up diagnosis confirmed the FDG PET-based categorization in 60 patients (88%, 4 false negative and 4 false positive cases with respect to detection of neurodegeneration). The fraction of correct PET-based categorization did not differ between patients with delirium in remission and patients without delirium (86% versus 89%, p = 0.666). Conclusion: Brain FDG PET is useful for the etiological diagnosis of CUCI in hospitalized geriatric patients, as well as in patients with delirium in remission.

Sustainable governance for small desert settlements: learning from the multi-settlement regionalism of Anmatjere Community Government Council

2008 ◽  
Vol 30 (1) ◽  
pp. 137 ◽  
Author(s):  
Will Sanders ◽  
Sarah Holcombe
Keyword(s):  
Local Government ◽  
Northern Territory ◽  
Governance Structures ◽  
History Of ◽  
Basic Desert ◽  
Central Australia ◽  
The Many ◽  
Governance Arrangements

In light of some basic desert demography, this paper examines governance patterns for small desert settlements. It traces policy histories which led to the emergence of highly localised, single settlement governance arrangements during the 1970s and ’80s. It also identifies the many pushes since within the Northern Territory local government system for more regional, multi-settlement governance structures. The paper goes on to examine the history of one such regional, multi-settlement arrangement in central Australia, the Anmatjere Community Government Council established in 1993. The paper details our work with this Council over the last 4 years on ‘issues of importance or concern’ to them. The paper aims to learn from the ACGC experience in order to inform the more radical restructuring of Northern Territory local government currently underway towards larger multi-settlement regionalism. It concludes with four specific lessons, the most important of which is that regionalism must build on single settlement localism.

scholarly journals Effective clustering for single cell sequencing cancer data

2019 ◽  
Author(s):  
Simone Ciccolella ◽  
Murray Patterson ◽  
Paola Bonizzoni ◽  
Gianluca Della Vedova
Keyword(s):  
Single Cell ◽  
Categorical Data ◽  
Euclidean Distance ◽  
Missing Values ◽  
False Negative ◽  
Ground Truth ◽  
Sequencing Data ◽  
Large Space ◽  
Cancer Data ◽  
Single Cell Sequencing

AbstractBackgroundSingle cell sequencing (SCS) technologies provide a level of resolution that makes it indispensable for inferring from a sequenced tumor, evolutionary trees or phylogenies representing an accumulation of cancerous mutations. A drawback of SCS is elevated false negative and missing value rates, resulting in a large space of possible solutions, which in turn makes infeasible using some approaches and tools. While this has not inhibited the development of methods for inferring phylogenies from SCS data, the continuing increase in size and resolution of these data begin to put a strain on such methods.One possible solution is to reduce the size of an SCS instance — usually represented as a matrix of presence, absence and missing values of the mutations found in the different sequenced cells — and infer the tree from this reduced-size instance. Previous approaches have used k-means to this end, clustering groups of mutations and/or cells, and using these means as the reduced instance. Such an approach typically uses the Euclidean distance for computing means. However, since the values in these matrices are of a categorical nature (having the three categories: present, absent and missing), we explore techniques for clustering categorical data — commonly used in data mining and machine learning — to SCS data, with this goal in mind.ResultsIn this work, we present a new clustering procedure aimed at clustering categorical vector, or matrix data — here representing SCS instances, called celluloid. We demonstrate that celluloid clusters mutations with high precision: never pairing too many mutations that are unrelated in the ground truth, but also obtains accurate results in terms of the phylogeny inferred downstream from the reduced instance produced by this method.Finally, we demonstrate the usefulness of a clustering step by applying the entire pipeline (clustering + inference method) to a real dataset, showing a significant reduction in the runtime, raising considerably the upper bound on the size of SCS instances which can be solved in practice.AvailabilityOur approach, celluloid: clustering single cell sequencing data around centroids is available at https://github.com/AlgoLab/celluloid/ under an MIT license.

Abstract T P45: Automated CSF Segmentation to Quantify Cerebral Edema Following Large Hemispheric Ischemic Stroke

Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Yasheng Chen ◽  
Qingyang Yuan ◽  
Raj Dhar ◽  
Kristin Guilliams ◽  
Laura Heitsch ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Cerebral Edema ◽  
Large Population ◽  
False Negative ◽  
Hounsfield Unit ◽  
Ground Truth ◽  
Mass Effect ◽  
Stroke Patients ◽  
Segmentation Strategy ◽  
Combined Strategy

Introduction: Cerebral edema with resultant mass effect is a potentially fatal consequence of ischemic stroke, but early and sensitive biomarkers of brain tissue compression are lacking. To quantify brain mass effect, we developed a novel, automated segmentation method to delineate CSF spaces in CT images from ischemic stroke patients. Methods: CTs from sixteen acute ischemic stroke patients (median NIHSS 16.5, median age 61.5 yrs, 14-92 hrs after stroke onset) were included after informed consent was obtained. After infarction, conventional CSF segmentation using Hounsfield unit (HU) thresholding is suboptimal due to infarct hypodensity. Utilizing manually delineated infarct and CSF spaces as training samples, we augmented conventional HU threshold segmentation with level sets, sparse regression and random forest segmentation methods. Using leave-one-out cross-validation, the combined approach was compared to HU thresholding using Dice ratios (a measure of the overlap between the segmented and the ground-truth CSF spaces). Results: Shown is an example of a CT brain slice segmented by HU thresholding and the combined strategy: false negative (red), false positive (green), and true positive (yellow). The Dice ratios for HU thresholding and the combined approaches were 58.2±16.3% and 68.9±14.6%, respectively, demonstrating the significantly improved performance for the combined strategy (p=0.0014). Conclusions: We have developed an advanced image segmentation strategy to delineate CSF spaces which outperforms conventional HU thresholding. An automated CSF segmentation strategy will permit quantification of cerebral edema in a large population of stroke patients, as required for genetic studies, for example.

Aerial Survey Techniques for Locating Abandoned Strip Mine Land

1980 ◽  
Vol 9 (4) ◽  
pp. 606-610
Author(s):  
L. E. Dattavio ◽  
R. P. Mroczynski ◽  
R. A. Weismiller
Keyword(s):  
Aerial Survey ◽  
Survey Techniques ◽  
Strip Mine

scholarly journals Overcoming the challenges of measuring the abundance of a cryptic macropod: is a qualitative approach good enough?

2014 ◽  
Vol 41 (1) ◽  
pp. 84 ◽  
Author(s):  
Karlene Bain ◽  
Adrian Wayne ◽  
Roberta Bencini
Keyword(s):  
Population Size ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Faecal Pellet ◽  
Survey Method ◽  
Population Abundance ◽  
Mark Recapture ◽  
Survey Technique ◽  
Threatened Taxa ◽  
Activity Indices

Context An understanding of population size and status is necessary for the implementation of appropriate conservation measures to recover threatened taxa. Mark–recapture studies at large spatial scales are impractical and expensive and a rapid survey technique is an attractive option to provide a measure of relative abundance for cryptic species, using indicators of activity. Aims The aim of our study was to use conventional methods for population estimation to calibrate a rapid survey technique for the quokka (Setonix brachyurus) in the southern forests of Western Australia, with a view to providing quantitative outcomes from this widely adopted monitoring approach. Methods We evaluated the accuracy of relative abundances obtained from the rapid survey technique by comparing them with abundance estimates obtained through established methods for the estimation of populations, including web-based mark–recapture and transect-based counts of activity indicators and sightings. Key results The rapid survey technique was effective at determining presence of quokkas but resulted in an over-estimation of population size because of inaccurate assumptions about occupancy and relative abundance of animals. An alternative survey method based on counts of fresh faecal-pellet groups was found to provide a more reliable and practical estimation of population abundance (R2 = 0.97). Conclusions Activity indices can be used to quantify population abundance, but only for indicators of activity that can be detected readily and for which freshness of activity can be determined. Implications Our findings suggest that a rapid survey based on activity indices can be used to evaluate quantitatively the population size of a species that is rare and potentially mobile at a landscape scale. The attraction of these techniques is that they provide a rapid and inexpensive survey option that is potentially applicable to any cryptic and/or threatened species and is practical for resource-constrained land managers.

scholarly journals Demography of feral camels in central Australia and its relevance to population control

2010 ◽  
Vol 32 (1) ◽  
pp. 11 ◽  
Author(s):  
A. R. Pople ◽  
S. R. McLeod
Keyword(s):  
Population Control ◽  
Northern Territory ◽  
Adult Survival ◽  
Large Mammals ◽  
Limited Data ◽  
Control Programs ◽  
Rate Of Increase ◽  
Zero Growth ◽  
Central Australia ◽  
Alternative Species

Since their release over 100 years ago, camels have spread across central Australia and increased in number. Increasingly, they are being seen as a pest, with observed impacts from overgrazing and damage to infrastructure such as fences. Irregular aerial surveys since 1983 and an interview-based survey in 1966 suggest that camels have been increasing at close to their maximum rate. A comparison of three models of population growth fitted to these, albeit limited, data suggests that the Northern Territory population has indeed been growing at an annual exponential rate of r = 0.074, or 8% per year, with little evidence of a density-dependent brake. A stage-structured model using life history data from a central Australian camel population suggests that this rate approximates the theoretical maximum. Elasticity analysis indicates that adult survival is by far the biggest influence on rate of increase and that a 9% reduction in survival from 96% is needed to stop the population growing. In contrast, at least 70% of mature females need to be sterilised to have a similar effect. In a benign environment, a population of large mammals such as camels is expected to grow exponentially until close to carrying capacity. This will frustrate control programs, because an ever-increasing number of animals will need to be removed for zero growth the longer that culling or harvesting effort is delayed. A population projection for 2008 suggests ~10 500 animals need to be harvested across the Northern Territory. Current harvests are well short of this. The ability of commercial harvesting to control camel populations in central Australia will depend on the value of animals, access to animals and the presence of alternative species to harvest when camels are at low density.

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