Research

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  • A regional spatial-retrofitting approach to geovisualise regional urban growth: An application to the Golden Horseshoe in Canada
    A regional spatial-retrofitting approach to geovisualise regional urban growth: An application to the Golden Horseshoe in Canada
    Understanding urban change in particular for larger regions has been a great demur in both regional planning and geography. One of the main challenges has been linked to the potential of modelling urban change. The absence of spatial data and size of areas of study limit the traditional urban monitoring approaches, which also do not take into account visualization techniques that share information with the community. This is the case of the Golden Horseshoe in southern Ontario in Canada, one of the fastest growing regions in North America. An unprecedented change on the urban environment has been witnessed, leading to an increased importance of awareness for future planning in the region. With a population greater than 8 million, the Golden Horseshoe is steadily showing symptoms of becoming a mega-urban region, joining surrounding cities into a single and diversified urban landscape. However, little effort has been done to understand these changes, nor to share information with policy makers, stakeholders and investors. These players are in need of the most diverse information on urban land use, which is seldom available from a single source. The spatio-temporal effect of the growth of this urban region could very well be the birth of yet another North American megacity. Therefore, from a spatial perspective there is demand for joint collaboration and adoption of a regional science perspective including land use and spatio-temporal configurations. This calls forth a novel technique that allows for assessment of urban and regional change, and supports decision-making without having the usual concerns of locational data availability. It is this sense, that we present a spatial-retrofitting model, with the objective of (i) retrofitting spatial land use based on current land use and land cover, and assessing proportional change in the past, leading to four spatial timestamps of the Golden Horseshoe’s land use, while (ii) integrating this in a multi-user open source web environment to facilitate synergies for decision-making. This combined approach is referred to as a regional-spatial-retrofitting approach (RSRA), where the conclusions permit accurate assessment of land use in past time frames based on Landsat imagery. The RSRA also allows for a collective vision of regional urban growth supporting local governance through a decision-making process adhering to Volunteered Geographic Information Systems. Urban land use change can be refined by means of contribution from end-users through a web environment, leading to a constant understanding and monitoring of urban land use and urban land use change.
    A review of mathematical models of influenza A infections within a host or cell culture: lessons learned and challenges ahead
    A review of mathematical models of influenza A infections within a host or cell culture: lessons learned and challenges ahead
    Most mathematical models used to study the dynamics of influenza A have thus far focused on the between-host population level, with the aim to inform public health decisions regarding issues such as drug and social distancing intervention strategies, antiviral stockpiling or vaccine distribution. Here, we investigate mathematical modeling of influenza infection spread at a different scale; namely that occurring within an individual host or a cell culture. We review the models that have been developed in the last decades and discuss their contributions to our understanding of the dynamics of influenza infections. We review kinetic parameters (e.g., viral clearance rate, lifespan of infected cells) and values obtained through fitting mathematical models, and contrast them with values obtained directly from experiments. We explore the symbiotic role of mathematical models and experimental assays in improving our quantitative understanding of influenza infection dynamics. We also discuss the challenges in developing better, more comprehensive models for the course of influenza infections within a host or cell culture. Finally, we explain the contributions of such modeling efforts to important public health issues, and suggest future modeling studies that can help to address additional questions relevant to public health., Beauchemin, C. A. A., & Handel, A. (2011). A review of mathematical models of influenza A infections within a host or cell culture: Lessons learned and challenges ahead. BMC Public Health, 11 Suppl 1(Suppl 1), S7-S7. doi:10.1186/1471-2458-11-S1-S7
    A simplified cervix model in response to induction balloon in pre-labour
    A simplified cervix model in response to induction balloon in pre-labour
    Background: Induction of labour is poorly understood even though it is performed in 20% of births in the United States. One method of induction, the balloon dilator applied with traction to the interior os of the cervix, engages a softening process, permitting dilation and effacement to proceed until the beginning of active labour. The purpose of this work is to develop a simple model capable of reproducing the dilation and effacement effect in the presence of a balloon. Methods: The cervix, anchored by the uterus and the endopelvic fascia was modelled in pre-labour. The spring-loaded, double sliding-joint, double pin-joint mechanism model was developed with a Modelica-compatible system, MapleSoft MapleSim 6.1, with a stiff Rosenbrock solver and 1E-4 absolute and relative tolerances. Total simulation time for pre-labour was seven hours and simulations ended at 4.50 cm dilation diameter and 2.25 cm effacement. Results: Three spring configurations were tested: one pin joint, one sliding joint and combined pin-joint-sliding-joint. Feedback, based on dilation speed modulated the spring values, permitting controlled dilation. Dilation diameter speed was maintained at 0.692 cm · hr−1 over the majority of the simulation time. In the sliding-joint-only mode the maximum spring constant value was 23800 N · m−1. In pin-joint-only the maximum spring constant value was 0.41 N·m· rad−1.With a sliding-joint-pin-joint pair the maximum spring constants are 2000 N · m−1 and 0.41 N · m · rad−1, respectively. Conclusions: The model, a simplified one-quarter version of the cervix, is capable of maintaining near-constant dilation rates, similar to published clinical observations for pre-labour. Lowest spring constant values are achieved when two springs are used, but nearly identical tracking of dilation speed can be achieved with only a pin joint spring. Initial and final values for effacement and dilation also match published clinical observations. These results provide a framework for development of electro-mechanical phantoms for induction training, as well as dilator testing and development., Smith, J. A. (2013). A simplified cervix model in response to induction balloon in pre-labour. Theoretical Biology & Medical Modelling, 10(1), 58-58. doi:10.1186/1742-4682-10-58
    A study of DiffServ based QoS issues in next generation mobile networks
    A study of DiffServ based QoS issues in next generation mobile networks
    To provide data rates of the order of hundreds of Mbps and multimedia services, standardization efforts for next generation (4G) systems are focusing on target technologies and seamless connectivity through various types of networks, including wireline networks and WLANs. Different types of multiple access techniques, such as the ones based on multicarrier CDMA and OFDM (orthogonal frequency division multiplexing) have been proposed. There is a need for functional integration of the multiple networks, and, with the evolution of IPv6 and QoS support for IP networks, an IP based interconnectivity is best suited. A QoS aware adaptive radio resource management technique based on multi-code multicarrier CDMA is discussed. We develop a novel radio access method and develop algorithms for allocating and controlling radio network resources so that system performance can be maximized and guaranteed QoS for multimedia services can be provided within the DiffServ environment., Canadian Conference on Electrical and Computer Engineering, May 2-5, 2004. Volume: 4: 2359 - 2362.
    A survey of diet self-efficacy and food intake in students with high and low perceived stress.
    A survey of diet self-efficacy and food intake in students with high and low perceived stress.
    Objective: Given the rise in obesity and obesity-related disorders, understanding the relationship between stress, self-efficacy and food choice in young adulthood may have implications for preventing negative health outcomes later in life that stem from poor eating habits. The current study examined whether stress levels and diet self-efficacy may be associated with unhealthy eating habits in young adults. Methods: Male and female undergraduate students (N = 136) completed questionnaires that tap into diet self-efficacy (DSE), perceived stress (PS), sodium, and fat intake. Sex differences in choice of food were predicted, and low levels of perceived stress and high diet self-efficacy were expected to be associated with lower fat and sodium intake. Results: Findings indicate an interaction between perceived stress and diet self-efficacy on fat intake and a main effect for diet self-efficacy on sodium intake in this population. As expected, low levels of perceived stress and high diet self-efficacy were associated with the lowest levels of fat and sodium intake in students. Findings were driven by females. Conclusions: This study provides preliminary evidence that diet self-efficacy and perceived stress levels relate to nutrient intake in young adult females, and that increasing diet self-efficacy and reducing perceived stress in young adult females may lead to reductions in fat and sodium intake, leading to healthier eating habits., Nastaskin, R. S., & Fiocco, A. J. (2015). A survey of diet self-efficacy and food intake in students with high and low perceived stress. Nutrition Journal, 14, 42.
    A systematic literature review of diabetes self-management education features to improve diabetes education in women of Black African/Caribbean and Hispanic/Latin American ethnicity, Patient Education and Counseling
    A systematic literature review of diabetes self-management education features to improve diabetes education in women of Black African/Caribbean and Hispanic/Latin American ethnicity, Patient Education and Counseling
    Abstract: Objective This systematic literature review aims to identify diabetes self-management education (DSME) features to improve diabetes education for Black African/Caribbean and Hispanic/Latin American women with Type 2 diabetes mellitus. Methods We conducted a literature search in six health databases for randomized controlled trials and comparative studies. Success rates of intervention features were calculated based on effectiveness in improving glycosolated hemoglobin (HbA1c), anthropometrics, physical activity, or diet outcomes. Calculations of rate differences assessed whether an intervention feature positively or negatively affected an outcome. Results From 13 studies included in our analysis, we identified 38 intervention features in relation to their success with an outcome. Five intervention features had positive rate differences across at least three outcomes: hospital-based interventions, group interventions, the use of situational problem-solving, frequent sessions, and incorporating dietitians as interventionists. Six intervention features had high positive rate differences (i.e. ≥50%) on specific outcomes. Conclusion Different DSME intervention features may influence broad and specific self-management outcomes for women of African/Caribbean and Hispanic/Latin ethnicity. Practical implications With the emphasis on patient-centered care, patients and care providers can consider options based on DSME intervention features for its broad and specific impact on outcomes to potentially make programming more effective., Gucciardi, E., Chan, V., Manuel, L. and Sidani, S. (2013). A systematic literature review of diabetes self-management education features to improve diabetes education in women of Black African/Caribbean and Hispanic/Latin American ethnicity. Patient Education and Counseling, 92(2), pp.235-245.
    A systematic review of the effectiveness of advanced practice nurses in long-term care
    A systematic review of the effectiveness of advanced practice nurses in long-term care
    To report quantitative evidence of the effectiveness of advanced practice nursing roles, clinical nurse specialists and nurse practitioners, in meeting the healthcare needs of older adults living in long-term care residential settings. Although studies have examined the effectiveness of advanced practice nurses in this setting, a systematic review of this evidence has not been conducted. Quantitative systematic review. Twelve electronic databases were searched (1966-2010); leaders in the field were contacted; and personal files, reference lists, pertinent journals, and websites were searched for prospective studies with a comparison group. Studies that met inclusion criteria were reviewed for quality, using a modified version of the Cochrane Effective Practice and Organisation of Care Review Group risk of bias assessment criteria. Four prospective studies conducted in the USA and reported in 15 papers were included. Long-term care settings with advanced practice nurses had lower rates of depression, urinary incontinence, pressure ulcers, restraint use, and aggressive behaviours; more residents who experienced improvements in meeting personal goals; and family members who expressed more satisfaction with medical services. Advanced practice nurses are associated with improvements in several measures of health status and behaviours of older adults in long-term care settings and in family satisfaction. Further exploration is needed to determine the effect of advanced practice nurses on health services use; resident satisfaction with care and quality of life; and the skills, quality of care, and job satisfaction of healthcare staff., Donald, F., Martin‐Misener, R., Carter, N., Donald, E. E., Kaasalainen, S., Wickson‐Griffiths, A.. . DiCenso, A. (2013). A systematic review of the effectiveness of advanced practice nurses in long‐term care. Journal of Advanced Nursing, 69(10), 2148-2161. doi:10.1111/jan.12140
    A systematic review of web-based educational interventions
    A systematic review of web-based educational interventions
    A complement to in-hospital educational interventions is web-based patient education accessed during the home recovery period. While findings demonstrate the effectiveness of web-based patient education interventions on patient outcomes, they fall short of identifying the characteristics that are associated with desired outcomes. The purpose of this systematic review was to determine the characteristics of web-based patient education interventions that are associated with producing changes in self-care behaviours. A systematic review involving 19 studies was conducted to determine the most effective components of a web-based intervention. Findings suggest that the most effective form of web-based patient education is one that is interactive and allows patients to navigate the online system on their own. The findings from this systematic review allow for the design of a web-based educational intervention that will promote increased performance of self-care behaviours during the home recovery period., Fredericks, S., Martorella, G., & Catallo, C. (2015). A systematic review of web-based educational interventions. Clinical Nursing Research, 24(1), 91-113.
    A theory of sharecropping: the role of price behavior and imperfect competition
    A theory of sharecropping: the role of price behavior and imperfect competition
    This paper proposes a theory of sharecropping on the basis of price behavior in agriculture and imperfectly competitive nature of rural product markets. We consider a contractual setting between one landlord and one tenant with seasonal variation of price, where the tenant receives a low price for his output while the landlord can sell his output at a higher price by incurring a cost of storage. We consider two different classes of contracts: (i) tenancy contracts and (ii) crop-buying contracts. It is shown that sharecropping is the optimal form within tenancy contracts and it also dominates crop-buying contracts provided the price variation is not too large. Then we consider interlinked contracts that have both tenancy and crop-buying elements and show that there are multiple optimal interlinked contracts. Finally, proposing an equilibrium refinement that incorporates imperfect competition in the rural product market, it is shown that the unique contract that is robust to this refinement results in sharecropping., Also available for download here: http://mpra.ub.uni-muenchen.de/14898/
    A ‘Natural’ Approach to Design
    A ‘Natural’ Approach to Design
    Current design processes are all generally similar in approach, but none yet address sustainability directly. When sustainable design is pursued, bio-inspired design or biomimicry are invariably used. These approaches attempt to reuse principles found in nature to conceptualize artifact designs. However, sustainable design approaches have yet to be integrated into typical design processes as they occur in practice; these methods generally work by seeking solutions only on a case-by-case basis. As a result, sustainable design methods like biomimicry tend to be used as ancillary or "after the fact" techniques. To fully integrate sustainability into design processes, the authors believe we must look more deeply at the processes that occur in nature and that have led to the organisms often referred to in biomimicry and related methods.The authors’ study of natural evolutionary processes has led them to believe that there is signifi- cant similarity in the way successive generations of artifacts and organisms change. We found that we could describe processes in generic terms that applied equally well to natural evolution and the way that artifacts change over time: that is to say, we found an analogy between generational changes in artifacts and in organisms. The authors are now delving into more detail, and are finding that the analogy can extend to cover natural selection, mutation, and genetic structures. A detailed explanation of this analogy, working at several different levels, is given in this paper. Furthermore, natural and artificial lifecycle processes are shown to be nearly identical.Since the analogy appears to hold well at many levels of detail, the authors propose to create a ge- netic structure (a genome) for artifacts. We contend that such a structure would be useful for designers. For example, we find that using the structure of the analogy as a guide can help reduce complexity of design problems. Also, we show that the artificial “genes” lend themselves to description via pattern languages, which are also known to reduce problem complexity. We hypothesize that using pattern languages to represent an artificial genome for designed artifacts will result in a useful, more holistic approach to sustainable design - one that is literally inspired by nature., Preprint.
    AMP-Activated Protein Kinase Regulates the Cell Surface Proteome and Integrin Membrane Traffic
    AMP-Activated Protein Kinase Regulates the Cell Surface Proteome and Integrin Membrane Traffic
    The cell surface proteome controls numerous cellular functions including cell migration and adhesion, intercellular communication and nutrient uptake. Cell surface proteins are controlled by acute changes in protein abundance at the plasma membrane through regulation of endocytosis and recycling (endomembrane traffic). Many cellular signals regulate endomembrane traffic, including metabolic signaling; however, the extent to which the cell surface proteome is controlled by acute regulation of endomembrane traffic under various conditions remains incompletely understood. AMP-activated protein kinase (AMPK) is a key metabolic sensor that is activated upon reduced cellular energy availability. AMPK activation alters the endomembrane traffic of a few specific proteins, as part of an adaptive response to increase energy intake and reduce energy expenditure. How increased AMPK activity during energy stress may globally regulate the cell surface proteome is not well understood. To study how AMPK may regulate the cell surface proteome, we used cell-impermeable biotinylation to selectively purify cell surface proteins under various conditions. Using ESI-MS/MS, we found that acute (90 min) treatment with the AMPK activator A-769662 elicits broad control of the cell surface abundance of diverse proteins. In particular, A-769662 treatment depleted from the cell surface proteins with functions in cell migration and adhesion. To complement our mass spectrometry results, we used other methods to show that A-769662 treatment results in impaired cell migration. Further, A-769662 treatment reduced the cell surface abundance of β1-integrin, a key cell migration protein, and AMPK gene silencing prevented this effect. While the control of the cell surface abundance of various proteins by A-769662 treatment was broad, it was also selective, as this treatment did not change the cell surface abundance of the transferrin receptor. Hence, the cell surface proteome is subject to acute regulation by treatment with A-769662, at least some of which is mediated by the metabolic sensor AMPK., Ross E, Ata R, Thavarajah T, Medvedev S, Bowden P, Marshall JG, et al. (2015) AMP-Activated Protein Kinase Regulates the Cell Surface Proteome and Integrin Membrane Traffic. PLoS ONE 10(5): e0128013.
    Absence of Evidence and Evidence of Absence
    Absence of Evidence and Evidence of Absence
    I defend the first premise of William Rowe’s well-known arguments from evil against influential criticisms due to William Alston. I next suggest that the central inference in Rowe’s arguments is best understood to move from the claim that we have an absence of evidence of a satisfactory theodicy to the claim that we have evidence of absence of such a theodicy. I endorse the view which holds that this move succeeds only if it is reasonable to believe that (roughly) if there were such a theodicy, we would probably know it. After conceding that there may be modest prima facie support for this latter claim via the Principle of Credulity, I consider and reject four more ambitious arguments in its favour. I conclude that this necessary condition on Rowe’s crucial inference has not been shown to be satisfied., This paper appears in Faith and Philosophy 24 (2007): 203-228. The published version can be found online at: http://www.pdcnet.org/collection/faithphil_2007_0024_0002_0203_0228.pdf .