Self-assessed Contrast-Maximizing Adaptive Region Growing

In the context of an experimental virtual-reality surgical planning software platform, we propose a fully self-assessed adaptive region growing segmentation algorithm. Our method successfully delineates main tissues relevant to head and neck reconstructive surgery, such as skin, fat, muscle/organs, and bone. We rely on a standardized and self-assessed region-based approach to deal with a great variety of imaging conditions with minimal user intervention, as only a single-seed selection stage is required. The detection of the optimal parameters is managed internally using a measure of the varying contrast of the growing regions. Validation based on synthetic images, as well as truly-delineated real CT volumes, is provided for the reader’s evaluation

Throwing enhances humeral shaft cortical bone properties in pre-pubertal baseball players: a 12-month longitudinal pilot study

Objectives: To explore throwing athletes as a prospective, within-subject controlled model for studying the response of the skeleton to exercise. Methods: Male pre-pubertal throwing athletes (n=12; age=10.3±0.6 yrs) had distal humerus cortical volumetric bone mineral density (Ct.vBMD), cortical bone mineral content (Ct.BMC), total area (Tt.Ar), cortical area (Ct.Ar), medullary area (Me.Ar), cortical thickness (Ct.Th) and polar moment of inertia (IP) assessed within their throwing (exercised) and nonthrowing (control) arms by peripheral quantitative computed tomography at baseline and 12 months. Throwing-to-nonthrowing arm percent differences (i.e. bilateral asymmetry) were compared over time. Results: Over 12 months, the throwing arm gained 4.3% (95% Cl=1.1% to 7.5%), 2.9% (95% Cl=0.3% to 5.4%), 3.9% (95% Cl=0.7% to 7.0%), and 8.2% (95% Cl=2.0% to 6.8%) more Ct.BMC, Ct.Ar, Tt.Ar, and IP than the nonthrowing arm, respectively (all p<0.05). There was no significant effect of throwing on Ct.vBMD, Ct.Th and Me.Ar (all p=0.18-0.82). Conclusion: Throwing induced surface-specific cortical bone adaptation at the distal humeral diaphysis that contributed to a gain in estimated strength. These longitudinal pilot data support the utility of throwing athletes as a within-subject controlled model to explore factors influencing exercise-induced bone adaptation during the critical growing years

Maximal Contrast Adaptive Region Growing for CT Airway Tree Segmentation

In this paper we propose a fully self-assessed adaptive region growing airway segmentation algorithm. We rely on a standardized and self-assessed region-based approach to deal with varying imaging conditions. Initialization of the algorithm requires prior knowledge of trachea location. This can be provided either by manual seeding or by automatic trachea detection in upper airway tree image slices. The detection of the optimal parameters is managed internally using a measure of the varying contrast of the growing region. Extensive validation is provided for a set of 20 chest CT scans. Our method exhibits very low leakage into the lung parenchyma, so even though the smaller airways are not obtained from the region growing, our fully automatic technique can provide robust and accurate initialization for other method

Fast parameter-free region growing segmentation with application to surgical planning

In this paper, we propose a self-assessed adaptive region growing segmentation algorithm. In the context of an experimental virtual-reality surgical planning software platform, our method successfully delineates main tissues relevant for reconstructive surgery, such as fat, muscle, and bone. We rely on a self-tuning approach to deal with a great variety of imaging conditions requiring limited user intervention (one seed). The detection of the optimal parameters is managed internally using a measure of the varying contrast of the growing region, and the stopping criterion is adapted to the noise level in the dataset thanks to the sampling strategy used for the assessment function. Sampling is referred to the statistics of a neighborhood around the seed(s), so that the sampling period becomes greater when images are noisier, resulting in the acquisition of a lower frequency version of the contrast function. Validation is provided for synthetic images, as well as real CT datasets. For the CT test images, validation is referred to manual delineations for 10 cases and to subjective assessment for another 35. High values of sensitivity and specificity, as well as Dice’s coefficient and Jaccard’s index on one hand, and satisfactory subjective evaluation on the other hand, prove the robustness of our contrast-based measure, even suggesting suitability for calibration of other region-based segmentation algorithms

Theories for influencer identification in complex networks

In social and biological systems, the structural heterogeneity of interaction networks gives rise to the emergence of a small set of influential nodes, or influencers, in a series of dynamical processes. Although much smaller than the entire network, these influencers were observed to be able to shape the collective dynamics of large populations in different contexts. As such, the successful identification of influencers should have profound implications in various real-world spreading dynamics such as viral marketing, epidemic outbreaks and cascading failure. In this chapter, we first summarize the centrality-based approach in finding single influencers in complex networks, and then discuss the more complicated problem of locating multiple influencers from a collective point of view. Progress rooted in collective influence theory, belief-propagation and computer science will be presented. Finally, we present some applications of influencer identification in diverse real-world systems, including online social platforms, scientific publication, brain networks and socioeconomic systems.Comment: 24 pages, 6 figure

CLIMATE CHANGE AND POVERTY REDUCTION IN SAHEL: CLIMATE RISK MANAGEMENT CONTRIBUTION TO POVERTY REDUCTION

Nowadays climate change event and poor population vulnerability become more severe and natural resources scarcity intensity increased. In order to mitigate climate change negative effects adaptive policies such as poverty reduction Strategy and National Adaptation Plan of Action (NAPA) as effective’s responsive strategies. There are also farmers traditional adaptation methods which are consider as local mainstreaming climate change adaptation framework. This paper has explore subjective qualitative evaluation of climate change risk management framework strategic and link its with poverty reduction strategy in the Sahel .Sahel is one of the most vulnerable areas in the world with lower HDI(0.2%) and have the highest poverty rate (over 45% of the people live below the poverty line). The study was focused on 9 Sahel countries (Senegal, Mauritania, Mali, Niger, Burkina-Faso, Nigeria, Chad, Soudan and Eritrea) and their Poverty Reduction Strategy Papers (PRSP) and National Adaptation Programmes of Action (NAPA) by assessing criteria such as: a) the consideration of climate change scenarios and the vulnerabilities of the country; b) the analysis of poverty-climate links; and c) the climate change institutional framework of the country. However Soudan and Eritrea don’t have PRSP and Nigeria don’t have NAPA. The results show that most Sahel countries does not included Climate change 2 effect in their PRSP (except Burkina-Faso) but have a better performance with NAPA framework elaboration. Burkina-Faso is Climate risk management model country in the region but policies have failed because of farmer’s difficult conditions to get access to credit and lack of good technical supports. NAPA and PRSP objectives did not achieved because majority of poor were excluded, inefficiency in domestic accounting systems and inefficient monitoring. Furthermore, donors funding problems, natural disasters such as floods or droughts; biophysical modeling and simulation insufficient data, lack of skilled labor are others reason. To conclude, it is illustrates that mainstreaming natural hazards into PRSP and the development of NAPA are a step forward into establishment of institutional process to incorporate climate change into national policies. The World Bank and the UNFCCC should coordinate efforts to support developing countries in their efforts to incorporate adaptation to climate change in PRSP. Country need to strength the coordination, networks and information flows between ministries, at different levels of government and civil society to have more efficient integration of climate change variables into poverty reduction and development strategies. Country's should also have sustainable funding and should not rely only on donor. Policies should target more vulnerable peoples, need good policies implementation and good monitoring.Sahel, Climate Change, Poverty Reduction, Adaptation Strategy., Resource /Energy Economics and Policy,

Broadacre farmers adapting to a changing climate

Abstract&nbsp;Data on the financial performance of a diverse set of 249 farm businesses in south-western Australia over the period 2002 to 2011 was collated and analysed. &nbsp;These 10 years were a period of challenging weather years, underpinned by a warming and drying trend in the region’s climate, frost events and marked price volatility.Based on a range of metrics, almost two-thirds (64%) of the farms in the sample were classed as growing or strong. A less secure group of farms that are at some potential financial risk formed 15% of the farm sample. Over the study period farm profitability, on average, improved, supported by productivity growth, in spite of no underlying improvement in the farmers’ terms of trade. &nbsp;Productivity improvement allowed most farm businesses, especially crop and mixed enterprise farm businesses, to prosper. &nbsp;The pathway to their profitability was not so much by investing in new technologies that may have shifted outwards farms’ production possibilities, but rather through better use of existing technologies, including technologies that offered scale economies. Also farmers’ shift into greater dependence on cropping, especially wheat production, was shown to be a sensible and successful adaptation strategy in many regions of south-western Australia, particularly the northern grainbelt.The unique and particular characteristics of each farm business were the main determinant of their business success. &nbsp;However, a few generalisations apply. &nbsp;Due to seasonal and market conditions during the study period more farms in the northern parts of the grainbelt in south-western Australia fared better. &nbsp;Also farmers whose businesses grew strongly over the study period on average displayed superior management capabilities and choices in many areas of farm management. &nbsp;In addition, these farmers were often more connected to their local community and achieved greater work-life balance.We conclude that as long as broadacre farmers in south-western Australia have on-going access to improved crop varieties and technologies that support the profitable growing of crops, especially wheat; and that they have access to farm management and business education then farmers are likely to be able to adapt to projected climate change. &nbsp;Provided that a farmer’s terms of trade does not become unduly adverse, and that farmers sensibly manage farm debt, then it seems highly likely that farmers who continue to rely on crop production, mostly wheat-growing, will persist as financially sound businesses in most parts of the study region, even in the face of projected climate change.Please cite this report as:Kingwell, R, Anderton, L, Islam, N, Xayavong, V, Wardell-Johnson, A, Feldman, D, Speijers, J 2013 Broadacre farmers adapting to a changing climate, National Climate Change Adaptation Research Facility, Gold Coast. pp.171.Data on the financial performance of a diverse set of 249 farm businesses in south-western Australia over the period 2002 to 2011 was collated and analysed. &nbsp;These 10 years were a period of challenging weather years, underpinned by a warming and drying trend in the region’s climate, frost events and marked price volatility.Based on a range of metrics, almost two-thirds (64%) of the farms in the sample were classed as growing or strong. A less secure group of farms that are at some potential financial risk formed 15% of the farm sample. Over the study period farm profitability, on average, improved, supported by productivity growth, in spite of no underlying improvement in the farmers’ terms of trade. &nbsp;Productivity improvement allowed most farm businesses, especially crop and mixed enterprise farm businesses, to prosper. &nbsp;The pathway to their profitability was not so much by investing in new technologies that may have shifted outwards farms’ production possibilities, but rather through better use of existing technologies, including technologies that offered scale economies. Also farmers’ shift into greater dependence on cropping, especially wheat production, was shown to be a sensible and successful adaptation strategy in many regions of south-western Australia, particularly the northern grainbelt.The unique and particular characteristics of each farm business were the main determinant of their business success. &nbsp;However, a few generalisations apply. &nbsp;Due to seasonal and market conditions during the study period more farms in the northern parts of the grainbelt in south-western Australia fared better. &nbsp;Also farmers whose businesses grew strongly over the study period on average displayed superior management capabilities and choices in many areas of farm management. &nbsp;In addition, these farmers were often more connected to their local community and achieved greater work-life balance.We conclude that as long as broadacre farmers in south-western Australia have on-going access to improved crop varieties and technologies that support the profitable growing of crops, especially wheat; and that they have access to farm management and business education then farmers are likely to be able to adapt to projected climate change. &nbsp;Provided that a farmer’s terms of trade does not become unduly adverse, and that farmers sensibly manage farm debt, then it seems highly likely that farmers who continue to rely on crop production, mostly wheat-growing, will persist as financially sound businesses in most parts of the study region, even in the face of projected climate change

Computerized Analysis of Magnetic Resonance Images to Study Cerebral Anatomy in Developing Neonates

The study of cerebral anatomy in developing neonates is of great importance for the understanding of brain development during the early period of life. This dissertation therefore focuses on three challenges in the modelling of cerebral anatomy in neonates during brain development. The methods that have been developed all use Magnetic Resonance Images (MRI) as source data. To facilitate study of vascular development in the neonatal period, a set of image analysis algorithms are developed to automatically extract and model cerebral vessel trees. The whole process consists of cerebral vessel tracking from automatically placed seed points, vessel tree generation, and vasculature registration and matching. These algorithms have been tested on clinical Time-of- Flight (TOF) MR angiographic datasets. To facilitate study of the neonatal cortex a complete cerebral cortex segmentation and reconstruction pipeline has been developed. Segmentation of the neonatal cortex is not effectively done by existing algorithms designed for the adult brain because the contrast between grey and white matter is reversed. This causes pixels containing tissue mixtures to be incorrectly labelled by conventional methods. The neonatal cortical segmentation method that has been developed is based on a novel expectation-maximization (EM) method with explicit correction for mislabelled partial volume voxels. Based on the resulting cortical segmentation, an implicit surface evolution technique is adopted for the reconstruction of the cortex in neonates. The performance of the method is investigated by performing a detailed landmark study. To facilitate study of cortical development, a cortical surface registration algorithm for aligning the cortical surface is developed. The method first inflates extracted cortical surfaces and then performs a non-rigid surface registration using free-form deformations (FFDs) to remove residual alignment. Validation experiments using data labelled by an expert observer demonstrate that the method can capture local changes and follow the growth of specific sulcus

Diagnostic applications of next generation sequencing: working towards quality standards

Over the past 6 years, next generation sequencing (NGS) has been established as a valuable high-throughput method for research in molecular genetics and has successfully been employed in the identification of rare and common genetic variations. All major NGS technology companies providing commercially available instruments (Roche 454, Illumina, Life Technologies) have recently marketed bench top sequencing instruments with lower throughput and shorter run times, thereby broadening the applications of NGS and opening the technology to the potential use for clinical diagnostics. Although the high expectations regarding the discovery of new diagnostic targets and an overall reduction of cost have been achieved, technological challenges in instrument handling, robustness of the chemistry and data analysis need to be overcome. To facilitate the implementation of NGS as a routine method in molecular diagnostics, consistent quality standards need to be developed. Here the authors give an overview of the current standards in protocols and workflows and discuss possible approaches to define quality criteria for NGS in molecular genetic diagnostics