A note on cash-in-advance constraints in continuous time
This paper demonstrates a robust proof of the continuous-time transformations of Stockman's cash-in-advance constraints. When the constraint applies to consumption and capital purchases, monetary growth lowers steady state consumption and capital. When the constraint applies only to consumption purchases, monetary growth is superneutral., Also available for download from:
A practical servomotor project: combining the Web with simulation tools to solidify concepts in undergraduate control education
Current technology enables the lecturer to use computer tools to enhance the conceptualisation of lecture material. This can be especially useful in an engineering curriculum, as the course material can be rendered less abstract through visual illustration of difficult mathematical concepts. In this paper, we present an example of a multimedia enhanced course in linear control theory, taught by authors at Ryerson Polytechnic University (Toronto, Canada). In our implementation of the course, we combine software simulations of practical systems to illustrate control theory concepts with extensive online course notes to assist with comprehension. Followup analysis shows that the use of the WWW and computer tools to enhance the learning process leads to increased enthusiasm, comprehension, and information retention. A review of the process required to create the technology enabled learning environment shows that initially there is a great deal of work involved. However, we conclude that the effort is justified by allowing a positive qualitative change in the way we educate engineering students, Proceedings of the 1998 American Control Conference. 21-26 Jun 1998: Volume 2: 1309-1313.
A randomized controlled dismantling trial of post-workshop consultation strategies to increase effectiveness and fidelity to an evidence-based psychotherapy for posttraumatic stress disorder
Background: Posttraumatic Stress Disorder (PTSD) is a serious mental health condition with substantial costs to individuals and society. Among military veterans, the lifetime prevalence of PTSD has been estimated to be as high as 20%. Numerous research studies have demonstrated that short-term cognitive-behavioral psychotherapies, such as Cognitive Processing Therapy (CPT), lead to substantial and sustained improvements in PTSD symptoms. Despite known benefits, only a minority of clinicians provide these therapies. Transferring this research knowledge into clinical settings remains one of the largest hurdles to improving the health of veterans with PTSD. Attending a workshop alone is insufficient to promote adequate knowledge transfer and sustained skill; however, relatively little
research has been conducted to identify effective post-training support strategies.
Methods: The current study investigates whether clinicians receiving post-workshop support (six-month duration) will deliver CPT with greater fidelity (i.e., psychotherapy adherence and competence) and have improved patient outcomes compared with clinicians receiving no formal post-workshop support. The study conditions are: technology-enhanced group tele-consultation; standard group tele-consultation; and fidelity assessment with no consultation. The primary outcome is independent assessment (via audio-recordings) of the clinicians’ adherence and competence in delivering CPT. The secondary outcome is observed changes in patient symptoms during and following treatment as a function of clinician fidelity. Post-consultation interviews with clinicians will help identify facilitators and barriers to psychotherapy skill acquisition. The study results will inform how best to implement and
transfer evidence-based psychotherapy (e.g., CPT) to clinical settings to attain comparable outcomes to those observed in research settings.
Discussion: Findings will deepen our understanding of how much and what type of support is needed following a workshop to help clinicians become proficient in delivering a new protocol. Several influences on clinician learning and patient outcomes will be discussed. An evidence-based model of clinical consultation will be developed, with the ultimate goal of informing policy and influencing best practice in clinical consultation.
Trial registration: ClinicalTrials.gov: NCT01861769, Wiltsey Stirman, S., Shields, N., Deloriea, J., Landy, M. S. H., Belus, J. M., Maslej, M. M., & Monson, C. M. (2013). A randomized controlled dismantling trial of post-workshop consultation strategies to increase effectiveness and fidelity to an evidence-based psychotherapy for posttraumatic stress disorder. Implementation Science : IS, 8, 82.
A realist review of brief interventions for alcohol misuse delivered in emergency departments
Background: Brief interventions (BIs) involve screening for alcohol misuse and providing feedback to patients
about their use, with the aim of reducing alcohol consumption and related consequences. BIs have been implemented
in various healthcare settings, including emergency departments (ED), where they have been found to contribute
mixed results in their ability to address alcohol misuse among adults. Mechanisms through which BIs work and
contextual factors impacting BI effectiveness are not clear. The purpose of this review was to understand how, for
whom, and under what circumstances BIs work for adults misusing alcohol and who have been admitted to an
ED. A realist review was chosen to answer these questions as realist reviews create context-mechanism-outcome
configurations, leading to the development of comprehensive and detailed theories; in this case explaining how
and for whom BIs work.
Methods: Databases including PsycINFO, Healthstar, CINAHL, Medline, and Nursing and Allied Health were
searched for articles published until December 2013. The search strategy focused on studies examining BIs that
targeted alcohol misuse among adults admitted into the ED. The search identified 145 relevant abstracts, of
which 36 were included in the review. The literature was synthesized qualitatively (immersion/crystallization).
Results: Four mechanisms were found within reviewed studies, including engagement in/retention of BI materials,
resolving ambivalence, increased awareness/insight into consequences of drinking, and increased self-efficacy/empowerment to use skills for change. The following contexts were found to impact mechanisms: emotional state, injury attributed to alcohol use, severity of alcohol use, and baseline stage of change.
Conclusions: This realist review provides advances in theories regarding which mechanisms to target during a BI and
which contexts create the most favorable conditions for these mechanisms to occur, ultimately leading to optimal BI
outcomes. These results can inform future clinical decision-making when delivering BIs in ED settings. Future research should conduct quantitative examination to confirm these findings.
Systematic review registration: PROSPERO CRD42013006549, Davey, C. J., Landy, M. S. H., Pecora, A., Quintero, D., & McShane, K. E. (2015). A realist review of brief interventions for alcohol misuse delivered in emergency departments. Systematic Reviews, 4(1), 45.
A realistic review of family-based interventions for children of substance abusing parents.
Millions of children across North America and Europe live in families with alcohol or drug abusing parents. These children are at risk for a number of negative social, emotional and developmental outcomes, including an increased likelihood of developing a substance use disorder later in life. Family-based intervention programs for children with substance abusing parents can yield positive outcomes. This study is a realist review of evaluations of family-based interventions aimed at improving psychosocial outcomes for children of substance abusing parents (COSAPs). The primary objectives were to uncover patterns of contextual factors and mechanisms that generate program outcomes, and advance program theory in this field.
Realist review methodology was chosen as the most appropriate method of systematic review because it is a theory-driven approach that seeks to explore mechanisms underlying program effectiveness (or lack thereof). A systematic and comprehensive search of academic and grey literature uncovered 32 documents spanning 7 different intervention programs. Data was extracted from the included documents using abstraction templates designed to code for contexts, mechanisms and outcomes of each program. Two candidate program theories of family addiction were used to guide data analysis: the family disease model and the family prevention model. Data analysis was undertaken by a research team using an iterative process of comparison and checking with original documents to determine patterns within the data.
Programs originating in both the family disease model and the family prevention model were uncovered, along with hybrid programs that successfully included components from each candidate program theory. Four demi-regularities were found to account for the effectiveness of programs included in this review: (1) opportunities for positive parent-child interactions, (2) supportive peer-to-peer relationships, (3) the power of knowledge, and (4) engaging hard to reach families using strategies that are responsive to socio-economic needs and matching services to client lived experience.
This review yielded new findings that had not otherwise been explored in COSAP program research and are discussed in order to help expand program theory. Implications for practice and evaluation are further discussed., Usher, A. M., McShane, K. E., & Dwyer, C. (2015). A realist review of family-based interventions for children of substance abusing parents. Systemic Reviews, 4, 177. doi:10.1186/s13643-015-0158-4
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
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
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
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.
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.
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.
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.
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
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.
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.
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.
Different DSME intervention features may influence broad and specific self-management outcomes for women of African/Caribbean and Hispanic/Latin ethnicity.
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
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