Experimental and computer simulation validation of ultrasound phase interference created by lateral inhomogeneity of transit time in replica bone marrow composite models

Purpose: The measurement of broadband ultrasonic attenuation (BUA) in cancellous bone for the assessment of osteoporosis follows a parabolic-type dependence with bone volume fraction; having minima values corresponding to both entire bone and entire marrow. Langton has recently proposed that the primary BUA mechanism may be significant phase interference due to variations in propagation transit time through the test sample as detected over the phase-sensitive surface of the receive ultrasound transducer. This fundamentally simple concept assumes that the propagation of ultrasound through a complex solid : liquid composite sample such as cancellous bone may be considered by an array of parallel ‘sonic rays’. The transit time of each ray is defined by the proportion of bone and marrow propagated, being a minimum (tmin) solely through bone and a maximum (tmax) solely through marrow. A Transit Time Spectrum (TTS), ranging from tmin to tmax, may be defined describing the proportion of sonic rays having a particular transit time, effectively describing lateral inhomogeneity of transit time over the surface of the receive ultrasound transducer. Phase interference may result from interaction of ‘sonic rays’ of differing transit times. The aim of this study was to test the hypothesis that there is a dependence of phase interference upon the lateral inhomogenity of transit time by comparing experimental measurements and computer simulation predictions of ultrasound propagation through a range of relatively simplistic solid:liquid models exhibiting a range of lateral inhomogeneities. Methods: A range of test models was manufactured using acrylic and water as surrogates for bone and marrow respectively. The models varied in thickness in one dimension normal to the direction of propagation, hence exhibiting a range of transit time lateral inhomogeneities, ranging from minimal (single transit time) to maximal (wedge; ultimately the limiting case where each sonic ray has a unique transit time). For the experimental component of the study, two unfocused 1 MHz ¾” broadband diameter transducers were utilized in transmission mode; ultrasound signals were recorded for each of the models. The computer simulation was performed with Matlab, where the transit time and relative amplitude of each sonic ray was calculated. The transit time for each sonic ray was defined as the sum of transit times through acrylic and water components. The relative amplitude considered the reception area for each sonic ray along with absorption in the acrylic. To replicate phase-sensitive detection, all sonic rays were summed and the output signal plotted in comparison with the experimentally derived output signal. Results: From qualtitative and quantitative comparison of the experimental and computer simulation results, there is an extremely high degree of agreement of 94.2% to 99.0% between the two approaches, supporting the concept that propagation of an ultrasound wave, for the models considered, may be approximated by a parallel sonic ray model where the transit time of each ray is defined by the proportion of ‘bone’ and ‘marrow’. Conclusions: This combined experimental and computer simulation study has successfully demonstrated that lateral inhomogeneity of transit time has significant potential for phase interference to occur if a phase-sensitive ultrasound receive transducer is implemented as in most commercial ultrasound bone analysis devices.

The 'Stakeholder Approach' to corporate governance and regulation : an assessment

The framework by which organizations are governed has been changed. A reason for this change is related with the force of stakeholders that compel the political power and the business society to review the ways in which companies are governed. Stakeholder thinking has gradually put this change at the center of research into business and society relations. Based on the stakeholder thinking, the corporate regulation framework has extended a new dimension in the business and society interface. This article assesses these issues.

The BRICS and the responsibility to protect : lessons from the Libyan and Syrian crises

The emerging ‘responsibility to protect’ (R2P) principle presents a significant challenge to the BRICS (Brazil, Russia, India, China and South Africa) states’ traditional emphasis on a strict Westphalian understanding of state sovereignty and non-interference in domestic affairs. Despite formally endorsing R2P at the 2005 World Summit, each of the BRICS has, to varying degrees, retained misgivings about coercive measures under the doctrine’s third pillar. This paper examines how these rising powers engaged with R2P during the 2011–2012 Libyan and Syrian civilian protection crises. The central finding is that although all five states expressed similar concerns over NATO’s military campaign in Libya, they have been unable to maintain a common BRICS position on R2P in Syria. Instead, the BRICS have splintered into two sub-groups. The first, consisting of Russia and China, remains steadfastly opposed to any coercive measures against Syria. The second, comprising the democratic IBSA states (India, Brazil and South Africa) has displayed softer, more flexible stances towards proposed civilian protection measures in Syria, although these three states also remain cautious about the implementation of R2P’s coercive dimension. This paper identifies a number of factors which help to explain this split, arguing that the failure to maintain a cohesive BRICS position on R2P is unsurprising given the many internal differences and diverging national interests between the BRICS members. Overall, the BRICS’ ongoing resistance to intervention is unlikely to disappear quickly, indicating that further attempts to operationalize R2P’s third pillar may prove difficult.

A leap into foodservice satisfaction in the private acute care setting

Monitoring foodservice satisfaction is a risk management strategy for malnutrition in the acute care sector, as low satisfaction may be associated with poor intake. This study aimed to investigate the relationship between age and foodservice satisfaction in the private acute care setting. Patient satisfaction was assessed using a validated tool, the Acute Care Hospital Foodservice Patient Satisfaction Questionnaire for data collected 2008–2010 (n = 779) at a private hospital, Brisbane. Age was grouped into three categories; <50 years, 51–70 years and >70 years. Fisher’s exact test assessed independence of categorical responses and age group; ANOVA or Kruskal–Wallis test was used for continuous variables. Dichotomised responses were analysed using logistic regression and odds ratios (95% confidence interval, p < 0.05). Overall foodservice satisfaction (5 point scale) was high (≥4 out of 5) and was independent of age group (p = 0.377). There was an increasing trend with age in mean satisfaction scores for individual dimensions of foodservice; food quality (p < 0.001), meal service quality (p < 0.001), staff service issues (p < 0.001) and physical environment (p < 0.001). A preference for being able to choose different sized meals (59.8% > 70 years vs 40.6% ≤50 years; p < 0.001) and response to ‘the foods are just the right temperature’ (55.3% >70 years vs 35.9% ≤50 years; p < 0.001) was dependent on age. For the food quality dimension, based on dichotomised responses (satisfied or not), the odds of satisfaction was higher for >70 years (OR = 5.0, 95% CI: 1.8–13.8; <50 years referent). These results suggest that dimensions of foodservice satisfaction are associated with age and can assist foodservices to meet varying generational expectations of clients.

Comment on "Local accumulation times for source, diffusion, and degradation models in two and three dimensions" [J. Chem. Phys. 138, 104121 (2013)]

In a recent paper, Gordon, Muratov, and Shvartsman studied a partial differential equation (PDE) model describing radially symmetric diffusion and degradation in two and three dimensions. They paid particular attention to the local accumulation time (LAT), also known in the literature as the mean action time, which is a spatially dependent timescale that can be used to provide an estimate of the time required for the transient solution to effectively reach steady state. They presented exact results for three-dimensional applications and gave approximate results for the two-dimensional analogue. Here we make two generalizations of Gordon, Muratov, and Shvartsman’s work: (i) we present an exact expression for the LAT in any dimension and (ii) we present an exact expression for the variance of the distribution. The variance provides useful information regarding the spread about the mean that is not captured by the LAT. We conclude by describing further extensions of the model that were not considered by Gordon,Muratov, and Shvartsman. We have found that exact expressions for the LAT can also be derived for these important extensions...

Socio-Spatial Approaches To Literacy Studies: Rethinking the Social Constitution and Politics of Space

Literacy studies have begun to examine the spatial dimension of literacy practices in a way that foregrounds space, and that considers space as constitutive to human relations and practices. This chapter provides an introduction to spatial literacy research, providing a guide to key theorists, themes, and studies that have shaped historical and new developments in spatial approaches to literacy practice and pedagogy. It begins by reconceptualising socio-spatial approaches to literacy research and defines terms. Intersections with related social theories are examined, with an emphasis on critical approaches and the politics of space. It clarifies the relationship between socio-spatial and socio-cultural paradigms, revisiting the spatial in seminal socio-cultural research. It covers new ground,including networks, flows, and deterritorialisation of literacy practice. The chapter concludes with challenges and recommendations for future language research and educational practice.

Improving business process models using observed behavior

Process-aware information systems (PAISs) can be configured using a reference process model, which is typically obtained via expert interviews. Over time, however, contextual factors and system requirements may cause the operational process to start deviating from this reference model. While a reference model should ideally be updated to remain aligned with such changes, this is a costly and often neglected activity. We present a new process mining technique that automatically improves the reference model on the basis of the observed behavior as recorded in the event logs of a PAIS. We discuss how to balance the four basic quality dimensions for process mining (fitness, precision, simplicity and generalization) and a new dimension, namely the structural similarity between the reference model and the discovered model. We demonstrate the applicability of this technique using a real-life scenario from a Dutch municipality.

Collaborative learning and critical thinking in technology-enhanced environments : an instructional design framework

The nature and characteristics of how learners learn today are changing. As technology use in learning and teaching continues to grow, its integration to facilitate deep learning and critical thinking becomes a primary consideration. The implications for learner use, implementation strategies, design of integration frameworks and evaluation of their effectiveness in learning environments cannot be overlooked. This study specifically looked at the impact that technology-enhanced learning environments have on different learners’ critical thinking in relation to eductive ability, technological self-efficacy, and approaches to learning and motivation in collaborative groups. These were explored within an instructional design framework called CoLeCTTE (collaborative learning and critical thinking in technology-enhanced environments) which was proposed, revised and used across three cases. The field of investigation was restricted to three key questions: 1) Do learner skill bases (learning approach and eductive ability) influence critical thinking within the proposed CoLeCTTE framework? If so, how?; 2) Do learning technologies influence the facilitation of deep learning and critical thinking within the proposed CoLeCTTE framework? If so, how?; and 3) How might learning be designed to facilitate the acquisition of deep learning and critical thinking within a technology-enabled collaborative environment? The rationale, assumptions and method of research for using a mixed method and naturalistic case study approach are discussed; and three cases are explored and analysed. The study was conducted at the tertiary level (undergraduate and postgraduate) where participants were engaged in critical technical discourse within their own disciplines. Group behaviour was observed and coded, attributes or skill bases were measured, and participants interviewed to acquire deeper insights into their experiences. A progressive case study approach was used, allowing case investigation to be implemented in a "ladder-like" manner. Cases 1 and 2 used the proposed CoLeCTTE framework with more in-depth analysis conducted for Case 2 resulting in a revision of the CoLeCTTE framework. Case 3 used the revised CoLeCTTE framework and in-depth analysis was conducted. The findings led to the final version of the framework. In Cases 1, 2 and 3, content analysis of group work was conducted to determine critical thinking performance. Thus, the researcher used three small groups where learner skill bases of eductive ability, technological self-efficacy, and approaches to learning and motivation were measured. Cases 2 and 3 participants were interviewed and observations provided more in-depth analysis. The main outcome of this study is analysis of the nature of critical thinking within collaborative groups and technology-enhanced environments positioned in a theoretical instructional design framework called CoLeCTTE. The findings of the study revealed the importance of the Achieving Motive dimension of a student’s learning approach and how direct intervention and strategies can positively influence critical thinking performance. The findings also identified factors that can adversely affect critical thinking performance and include poor learning skills, frustration, stress and poor self-confidence, prioritisations over learning; and inadequate appropriation of group role and tasks. These findings are set out as instructional design guidelines for the judicious integration of learning technologies into learning and teaching practice for higher education that will support deep learning and critical thinking in collaborative groups. These guidelines are presented in two key areas: technology and tools; and activity design, monitoring, control and feedback.

Thermal stability and hot-stage Raman spectroscopic study of Ca-montmorillonite modified with different surfactants : a comparative study

Three long chain cationic surfactants were intercalated into Ca-montmorillonite through ion exchangeand the obtained organoclays were characterized by X-ray diffraction (XRD), high resolution thermo-gravimetric analysis (TG) and Raman spectroscopy. The intercalation of surfactants not only changes thesurface properties of clay from hydrophilic to hydrophobic but also greatly increases the basal spacing ofthe interlayers based on XRD analysis. The thermal stability of organoclays intercalated with three sur-factants (TTAB, DTAB and CTAB) and the different arrangements of the surfactant molecules intercalatedinto Ca-montmorillonite were determined by TG-DTG analysis. A Raman spectroscopic study on the Ca-montmorillonite modified by three surfactants prepared at different concentrations provided the detailedconformational ordering of different intercalated long-chain surfactants under different conditions. Thewavenumber of the antisymmetric stretching mode is more sensitive than that of the symmetric stretch-ing mode to the mobility of the tail of the amine chain. At room temperature, the conformational orderingis more easily affected by the packing density in the lateral model. With the increase of the temperature,the positions of both the antisymmetric and symmetric stretching bands shift to higher wavenumbers,which indicates a decrease of conformational ordering. This study offers new insights into the struc-ture and properties of Ca-montmorillonite modified with different long chain surfactants. Moreover, theexperimental results confirm the potential applications of organic Ca-montmorillonites for the removalof organic impurities from aqueous media.

Harnessing SD and CSR within corporate self-regulation of weak economies : a meta-regulation approach

The semantic of the terms “sustainable development” and “corporate social responsibility” have changed over time to a point where these concepts have become two interrelated processes for ensuring the far-reaching development of society. Their convergence has given dimension to the environmental and corporate regulation mechanisms in strong economies. This article deals with the question of how the ethos of this convergence could be incorporated into the self-regulation of businesses in weak economies where nonlegal drivers are either inadequate or inefficient. It proposes that the policies for this incorporation should be based on the precepts of meta-regulation that have the potential to hold force majeure, economic incentives, and assistance-related strategies to reach an objective from the perspective of weak economies.

Importance of sustainability-related cost components in highway infrastructure : perspective of stakeholders in Australia

Highway infrastructure development typically requires major capital input. Unless planned properly, such requirements can cause serious financial constraints for investors. The push for sustainability adds a new dimension to the complexity of evaluating highway projects. Finding environmentally and socially responsible solutions for highway construction will improve its potential for acceptance by the society and in many instances the infrastructure's life span. Even so, the prediction and determination of a project's long-term financial viability can be a precarious exercise. Existing studies in this area have not indicated details of how to identify and deal with costs incurred in pursuing sustainability measures in highway infrastructure. This paper provides insights into the major challenges of implementing sustainability in highway project development in terms of financial concerns and obligations. It discusses the results from recent research through a literature study and a questionnaire survey of key industry stakeholders involved in highway infrastructure development. The research identified critical cost components relating to sustainability measures based on perspectives of industry stakeholders. All stakeholders believe sustainability related costs are an integral part of the decision making. However, the importance rating of these costs is relative to each stakeholder's core business objectives. This will influence the way these cost components are dealt with during the evaluation of highway investment alternatives and financial implications. This research encourages positive thinking among the highway infrastructure practitioners about sustainability. It calls for the construction industry to maximise sustainability deliverables while ensuring financial viability over the life cycle of highway infrastructure projects.

Sensing place : embodiment, sensoriality, kinesis, and children behind the camera

This article is a call to literacy teachers and researchers to embrace the possibility of attending more consciously to the senses in digital media production. Literacy practices do not occur only in the mind, but involve the sensoriality, embodiment, co-presence, and movement of bodies. This paper theorises the sensorial and embodied dimension of children’s filmmaking about place in two communities in Australia. The films were created by pre-teen Indigenous and non-Indigenous children in Logan, Queensland, and by Indigenous teenagers at the Warralong campus of the Strelley Community School in remote Western Australia. The films were created through engagement in cross-curricular units that sensitised the students’ experience of local places, gathering corporeal information through their sensing bodies as they interacted with the local ecology. The analysis highlights how the sensorial and bodily nature of literacy practice through documentary filmmaking was central to the children’s formation and representation of knowledge, because knowledge and literacy practices are not only acquired through the mind, but are also reliant on embodiment, sensoriality, co-presence, and kinesics of the body in place.

A simple method for fabricating 3-D multilayered composite scaffolds

One limitation of electrospinning stems from the charge build-up that occurs during processing, preventing further fibre deposition and limiting the scaffold overall thickness and hence their end-use in tissue engineering applications targeting large tissue defect repair. To overcome this, we have developed a technique in which thermally induced phase separation (TIPS) and electrospinning are combined. Thick three-dimensional, multilayered composite scaffolds were produced by simply stacking individual polycaprolactone (PCL) microfibrous electrospun discs into a cylindrical holder that was filled with a 3% poly(lactic-co-glycolic acid) (PLGA) solution in dimethylsulfoxide (a good solvent for PLGA but a poor one for PCL). The construct was quenched in liquid nitrogen and the solvent removed by leaching out in cold water. This technique enables the fabrication of scaffolds composed principally of electrospun membranes that have no limit to their thickness. The mechanical properties of these scaffolds were assessed under both quasi-static and dynamic conditions. The multilayered composite scaffolds had similar compressive properties to 5% PCL scaffolds fabricated solely by the TIPS methodology. However, tensile tests demonstrated that the multilayered construct outperformed a scaffold made purely by TIPS, highlighting the contribution of the electrospun component of the composite scaffold to enhancing the overall mechanical property slate. Cell studies revealed cell infiltration principally from the scaffold edges under static seeding conditions. This fabrication methodology permits the rapid construction of thick, strong scaffolds from a range of biodegradable polymers often used in tissue engineering, and will be particularly useful when large dimension electrospun scaffolds are required.

More than merely wicked : regulating sewage discharges and other unspeakable problems in environmental policy-making and planning

While the communicative turn in policy-making has encouraged the public deliberation of policy decisions it has arguably had a more limited impact on the ability of public processes to deal with wicked problems. Wicked policy problems are characterised by high levels of complexity, uncertainty and divergence of values. However, some wicked problems present the additional challenge of high levels of psychosocial sensitivity and verbal proscription. Because these unspeakable policy problems frequently involve a significant moral dimension, the regulation of intimate processes or bodies, and strong elements of abjection and symbolic pollution they are quite literally problems that we don’t like to think about or talk about. However, the potential environmental and social impacts of these problems require that they be addressed. In this paper I present the preliminary findings of a research project focussed on the idea of the unspeakable policy problem and how its unspeakable nature can impact upon public participation and policy and environmental outcomes.

Separable and non-separable discrete wavelet transform based texture features and image classification of breast thermograms

Highly sensitive infrared cameras can produce high-resolution diagnostic images of the temperature and vascular changes of breasts. Wavelet transform based features are suitable in extracting the texture difference information of these images due to their scale-space decomposition. The objective of this study is to investigate the potential of extracted features in differentiating between breast lesions by comparing the two corresponding pectoral regions of two breast thermograms. The pectoral regions of breastsare important because near 50% of all breast cancer is located in this region. In this study, the pectoral region of the left breast is selected. Then the corresponding pectoral region of the right breast is identified. Texture features based on the first and the second sets of statistics are extracted from wavelet decomposed images of the pectoral regions of two breast thermograms. Principal component analysis is used to reduce dimension and an Adaboost classifier to evaluate classification performance. A number of different wavelet features are compared and it is shown that complex non-separable 2D discrete wavelet transform features perform better than their real separable counterparts.