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Western University

2010

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D-Dimensional Bose Gases And The Lambert W Function, Sree Ram Valluri, J Tanguay, M Gil, D J. Jeffrey Dec 2010

D-Dimensional Bose Gases And The Lambert W Function, Sree Ram Valluri, J Tanguay, M Gil, D J. Jeffrey

Physics and Astronomy Publications

The applications of the Lambert W function (also known as the W function) to D-dimensional Bose gases are presented. We introduce two sets of families of logarithmic transcendental equations that occur frequently in thermodynamics and statistical mechanics and present their solution in terms of the W function. The low temperature T behavior of free ideal Bose gases is considered in three and four dimensions. It is shown that near condensation in four dimensions, the chemical potential μ and pressure P can be expressed in terms of T through the W function. The low T behavior of one- and two-dimensional ideal …


A Stakeholder Generated Conceptualization For Successful Return To Work Outcome Evaluation: A Concept Mapping Approach, Rhysa Leyshon Dec 2010

A Stakeholder Generated Conceptualization For Successful Return To Work Outcome Evaluation: A Concept Mapping Approach, Rhysa Leyshon

Electronic Thesis and Dissertation Repository

Measurement of return to work (RTW) lacks attention to outcomes of relevance to all stakeholders. The objective of this thesis was to define what constitutes a successful RTW outcome from a stakeholder perspective and determine how to best measure it. A concept mapping method was used to create a conceptualization of successful RTW outcome based on indicators of interest and importance to various stakeholders. RTW researchers were questioned and the literature was searched for measures that mapped to the conceptualization and concepts. Stakeholders, made up of RTW consumers and providers, generated 48 indicators of successful RTW which were subsequently grouped …


Occasioning Dialogic Spaces Of Innovation: The Pan-Canadian Ehr, Infoway And The Re-Scripting Of Healthcare, Akbar M. Saeed Dec 2010

Occasioning Dialogic Spaces Of Innovation: The Pan-Canadian Ehr, Infoway And The Re-Scripting Of Healthcare, Akbar M. Saeed

Electronic Thesis and Dissertation Repository

The Canadian public healthcare system appears to currently be under considerable strain. Escalating costs, dwindling budgets and growing patient dissatisfaction are just a few of the systemic pressures that have called into question our current ways of delivering healthcare. As a consequence, there is a growing recognition that renewal is needed, and that this renewal, to be successful, should meet the needs of a wide array of stakeholders, hence calling for unprecedented levels of collaboration among increasingly fragmented interests. In order to bring about this renewal, the federal government seems to be intent on implementing a pan-Canadian electronic health record …


Improvements In Cardiac Spect/Ct For The Purpose Of Tracking Transplanted Cells, Eric Sabondjian Dec 2010

Improvements In Cardiac Spect/Ct For The Purpose Of Tracking Transplanted Cells, Eric Sabondjian

Electronic Thesis and Dissertation Repository

Regenerative therapy via stem cell transplantation has received increased attention to help treat the myocardial injury associated with heart disease. Currently, the hybridisation of SPECT with X-ray CT is expanding the utility of SPECT. This thesis compared two SPECT/CT systems for attenuation correction using slow or fast-CT attenuation maps (mu-maps). We then developed a method to localize transplanted cells in relation to compromised blood flow in the myocardium following a myocardial infarction using SPECT/CT. Finally, a method to correct for image truncation was studied for a new SPECT/CT design that incorporated small field-of-view (FOV) detectors. Computer simulations compared gated-SPECT reconstructions …


Advanced Topics On State Complexity Of Combined Operations, Yuan Gao Dec 2010

Advanced Topics On State Complexity Of Combined Operations, Yuan Gao

Electronic Thesis and Dissertation Repository

State complexity is a fundamental topic in formal languages and automata theory. The study of state complexity is also strongly motivated by applications of finite automata in software engineering, programming languages, natural language and speech processing and other practical areas. Since many of these applications use automata of large sizes, it is important to know the number of states of the automata. In this thesis, we firstly discuss the state complexities of individual operations on regular languages, including union, intersection, star, catenation, reversal and so on. The state complexity of an operation on unary languages is usually different from that …


Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade Dec 2010

Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade

Electronic Thesis and Dissertation Repository

In the ongoing quest to extract more information from MRI images, there has arisen a need to rapidly map the flip angle. This has been primarily driven by the shift to stronger main field strengths, which bring with them improved SNR, but also new difficulties. In particular, the radio frequency field used to excite the magnetization can no longer be assumed uniform at field strengths of 3 Tesla and above. New rapid quantitative imaging techniques, such as DESPOT1 and DESPOT2, rely on accurate knowledge of the flip angle, and while this could safely be assumed to be the prescribed value …


Descending Central Series Of Free Pro-P-Groups, German A. Combariza Dec 2010

Descending Central Series Of Free Pro-P-Groups, German A. Combariza

Electronic Thesis and Dissertation Repository

In this thesis, we study the first three cohomology groups of the quotients of the descending central series of a free pro-p-group. We analyse the Lyndon-Hochschild- Serre spectral sequence up to degree three and develop what we believe is a new technique to compute the third cohomology group. Using Fox-Calculus we express the cocycles of a finite p-group G with coefficients on a certain module M as the kernel of a matrix composed by the derivatives of the relations of a minimal presentation for G. We also show a relation between free groups and finite fields, this is a new …


Wake Dynamics And Passive Flow Control Of A Blunt Trailing Edge Profiled Body, Lakshmana Sampat Doddipatla Dec 2010

Wake Dynamics And Passive Flow Control Of A Blunt Trailing Edge Profiled Body, Lakshmana Sampat Doddipatla

Electronic Thesis and Dissertation Repository

Wake flows behind two-dimensional bodies are dominated mainly by two types of coherent structures, namely, the Karman Benard vortices and the streamwise vortices, also referred to as rolls and ribs respectively. The three-dimensional wake instabilities lead to distinct instability modes (mode-A, mode-B and mode-C or mode S) depending on the flow Reynolds number and geometric shape. The present investigation explores the mechanism by which the flow transitions take place to three-dimensionality in the near wake of a profiled leading edge and blunt trailing edge body. Experiments consisting of a combination of Planar Laser Induced Fluorescence visualizations and Particle Image Velocimetry …


Toronto The Green: Pollution Probe And The Rise Of The Canadian Environmental Movement, Ryan Ernest O'Connor Dec 2010

Toronto The Green: Pollution Probe And The Rise Of The Canadian Environmental Movement, Ryan Ernest O'Connor

Electronic Thesis and Dissertation Repository

This dissertation utilizes the first fifteen years of Pollution Probe’s history (1969-1984) as a prism for examining the origins and development of environmental activism in Canada. The organization was pivotal in the evolution of environmentalist discourse and activism in Toronto, both through its own activities and its role in institution-building. Rooted in Toronto, Pollution Probe provides insight into the early history of the Canadian environmental movement, demonstrating the many ways that this movement differed from the one that took shape in the United States. As will be demonstrated, Pollution Probe was representative of the first wave of Canadian environmental non-governmental …


Reducing The Pain Of Childhood Vaccination: An Evidence-Based Clinical Practice Guideline, Anna Taddio, Mary Appleton, Robert Bortolussi, Christine Chambers, Vinita Dubey, Scott Halperin, Anita Hanrahan, Moshe Ipp, Donna Lockett, Noni Macdonald, Deana Midmer, Patricia Mousmanis, Valerie Palda, Karen Pielak, Rebecca Pillai Riddell, Michael Rieder, Jeffrey Scott, Vibhuti Shah Dec 2010

Reducing The Pain Of Childhood Vaccination: An Evidence-Based Clinical Practice Guideline, Anna Taddio, Mary Appleton, Robert Bortolussi, Christine Chambers, Vinita Dubey, Scott Halperin, Anita Hanrahan, Moshe Ipp, Donna Lockett, Noni Macdonald, Deana Midmer, Patricia Mousmanis, Valerie Palda, Karen Pielak, Rebecca Pillai Riddell, Michael Rieder, Jeffrey Scott, Vibhuti Shah

Paediatrics Publications

No abstract provided.


Reducing The Pain Of Childhood Vaccination: An Evidence-Based Clinical Practice Guideline (Summary), Anna Taddio, Mary Appleton, Robert Bortolussi, Christine Chambers, Vinita Dubey, Scott Halperin, Anita Hanrahan, Moshe Ipp, Donna Lockett, Noni Macdonald, Deana Midmer, Patricia Mousmanis, Valerie Palda, Karen Pielak, Rebecca Pillai Riddell, Michael Rieder, Jeffrey Scott, Vibhuti Shah Dec 2010

Reducing The Pain Of Childhood Vaccination: An Evidence-Based Clinical Practice Guideline (Summary), Anna Taddio, Mary Appleton, Robert Bortolussi, Christine Chambers, Vinita Dubey, Scott Halperin, Anita Hanrahan, Moshe Ipp, Donna Lockett, Noni Macdonald, Deana Midmer, Patricia Mousmanis, Valerie Palda, Karen Pielak, Rebecca Pillai Riddell, Michael Rieder, Jeffrey Scott, Vibhuti Shah

Paediatrics Publications

No abstract provided.


A Step Towards Continuous Production Of Nay Zeolite In Amorphous Silica Particles Using A Dry Process, Syed Sameen Ali Zaidi Dec 2010

A Step Towards Continuous Production Of Nay Zeolite In Amorphous Silica Particles Using A Dry Process, Syed Sameen Ali Zaidi

Electronic Thesis and Dissertation Repository

This thesis is focused on the synthesis of nano-size (50-100nm) NaY zeolite crystals inside the micro/meso pores of preshaped amorphous silica particles of size 50 micrometer using a dry process, which reduced several operational steps and the zeolite synthesis time that are generally required for current in-practice processes. Three types of reactors namely; polypropylene bottles, a stainless steel tubular reactor, and a novel vibrated baffles fluidized bed (VBFB) reactor coupled with infrared radiation emitters were used to evaluate the effects of different operating parameters on the synthesis of NaY zeolite. The synthesis process took place without using any structure directing …


The Role Of The Mcm2 Subunit In Regulating The Activities Of The Mcm2-7 Helicase, Brent E. Stead Dec 2010

The Role Of The Mcm2 Subunit In Regulating The Activities Of The Mcm2-7 Helicase, Brent E. Stead

Electronic Thesis and Dissertation Repository

The transmission of genetic information from parental to daughter cells requires the faithful duplication of an organism’s genome. Uncontrolled DNA replication can result in proliferative diseases, such as cancer. DNA replication requires a single-stranded DNA template to be produced from duplex DNA. In eukaryotes, DNA unwinding for replication is performed by the heterohexameric replicative helicase complex comprised of the minichromosome maintenance proteins 2 through 7.

Each of the Mcm2-7 subunits likely has a unique role in DNA binding and unwinding by the Mcm2-7 complex. The present study examines the role of the Saccharomyces cerevisiae Mcm2 subunit in regulating the activities …


Incentives For Optimal Allocation Of Hiv Prevention Resources, Monali M. Malvankar Dec 2010

Incentives For Optimal Allocation Of Hiv Prevention Resources, Monali M. Malvankar

Electronic Thesis and Dissertation Repository

The thesis consists of three main chapters on optimal incentives for a multi-level allocation process of HIV/AIDS prevention funds. HIV/AIDS prevention funds often traverse several levels of distribution. At each level, equity-based heuristics are often used by decision-makers that may lead to sub-optimal allocation. Mathematical programming models may help to allocate prevention funds optimally. Thus, incentives could be given to decision-makers to encourage optimal allocation.

Chapter 4 investigates the impact of incentives by developing a model in which an upper-level decision-maker (UD) allocates funds to a single lower-level decision-maker (LD) who then distributes funds to local programs. The UD makes …


Parenting At Midnight: Measuring Parents' Thoughts And Strategies To Help Young Children Sleep Through The Night, Aimee J. Coulombe Dec 2010

Parenting At Midnight: Measuring Parents' Thoughts And Strategies To Help Young Children Sleep Through The Night, Aimee J. Coulombe

Electronic Thesis and Dissertation Repository

Throughout the night, brief periods of arousal are common and not necessarily indicative of problematic sleep. Awakening without an easy return to sleep (“night-waking”), however, can be problematic for parents and children alike. Approximately 30% of preschool-aged children wake at least once per night and require parental intervention (“help or assistance”). Although parents’ responses to children’s night-waking (i.e., parents’ night-waking strategies) can determine the course of night-waking over time, very little is known about night-waking strategy use among parents of preschool-aged children. The purpose of the present dissertation was to lay the foundation upon which a better understanding of the …


Cross-Sectional Morphology And Mechanical Loading In Plio-Pleistocene Hominins: Implications For Locomotion And Taxonomy, Michele M. Bleuze Ms. Dec 2010

Cross-Sectional Morphology And Mechanical Loading In Plio-Pleistocene Hominins: Implications For Locomotion And Taxonomy, Michele M. Bleuze Ms.

Electronic Thesis and Dissertation Repository

This study explores locomotion and locomotor variability in Plio-Pleistocene hominins by examining cross-sectional properties and mechanical loading patterns in the proximal and midshaft femur of Paranthropus, fossil Homo sp. and H. erectus. Modern human and Pan models are used for comparative purposes. Cross-sectional properties in the proximal and midshaft femur of fossil hominins are examined to test the hypothesis that members of the same genus should exhibit similar locomotor behavior. In the proximal femur, fossil Homo sp. cluster with modern humans to the exclusion of Paranthropus, and East and South African Paranthropus cluster together. Group differences are primarily due to …


Perception Meets Action: Fmri And Behavioural Investigations Of Human Tool Use, Kenneth F. Valyear Dec 2010

Perception Meets Action: Fmri And Behavioural Investigations Of Human Tool Use, Kenneth F. Valyear

Electronic Thesis and Dissertation Repository

Tool use is essential and culturally universal to human life, common to hunter-gatherer and modern advanced societies alike. Although the neuroscience of simpler visuomotor behaviors like reaching and grasping have been studied extensively, relatively little is known about the brain mechanisms underlying learned tool use.

With learned tool use, stored knowledge of object function and use supervene requirements for action programming based on physical object properties. Contemporary models of tool use based primarily on evidence from the study of brain damaged individuals implicate a set of specialized brain areas underlying the planning and control of learned actions with objects, distinct …


Effects Of Acute Synchronous Whole-Body Vibration Exercise, Tom J. Hazell Dec 2010

Effects Of Acute Synchronous Whole-Body Vibration Exercise, Tom J. Hazell

Electronic Thesis and Dissertation Repository

Recently, whole-body vibration (WBV) exercise has been gaining interest in the health/fitness community for its reported beneficial outcomes. However, most of these have not been evaluated scientifically leading to some reservation in promoting this new exercise modality. The purpose of this dissertation was to assess the viability of WBV exercise to enhance several selected indices of health.

Study 1 demonstrated that the addition of WBV to an isometric semi-squat in young healthy men (n = 8, 25±2.6 y, 177±7.0 cm, 84±12.1 kg) resulted in increases in femoral artery blood flow and leg skin temperature vs the same exercise without vibration …


Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel Dec 2010

Identification Of Regions Responsible For The Open Conformation Of S100a10 Using Chimaeric S100a11/S100a10 Proteins, Liliana Santamaria-Kisiel

Electronic Thesis and Dissertation Repository

S100A11 is a dimeric, EF-hand calcium-binding protein. Calcium binding to S100A11 results in a large conformational change that uncovers a broad hydrophobic surface used to interact with phospholipid-binding proteins (annexins A1 and A2), and facilitate membrane vesiculation events. In contrast to other S100 proteins, S100A10 is unable to bind calcium due to deletion and substitution of calcium-ligating residues. Despite this, calcium-free S100A10 assumes an “open” conformation that is very similar to S100A11 in its calcium-bound state (Ca2+-S100A11). To understand how S100A10 is able to adopt an open conformation in the absence of calcium, seven chimeric proteins were constructed where regions …


Nickel-Based Catalysts For Gasification Of Glucose In Supercritical Water, Muhammad Badrul Islam Chowdhury Dec 2010

Nickel-Based Catalysts For Gasification Of Glucose In Supercritical Water, Muhammad Badrul Islam Chowdhury

Electronic Thesis and Dissertation Repository

Gasification of waste biomass to form hydrogen, H2, is a promising new source of green energy; while providing the additional benefit of treating challenging and hazardous waste streams that pollute the environment. Gasification of biomass in supercritical water (SCW) offers an attractive alternative to avoid the energy intensive drying process. In this approach, biomass is hydrolyzed by water into smaller molecules in the presence of a suitable catalyst. This study was aimed at developing an alumina supported nickel based non-noble metal catalyst suitable for biomass gasification in SCW. A lack of detailed characterization on fresh and spent catalysts in SCW …


The Problem Of Katholou (Universals) In Aristotle, Riin Sirkel Dec 2010

The Problem Of Katholou (Universals) In Aristotle, Riin Sirkel

Electronic Thesis and Dissertation Repository

My dissertation focuses on what I call Aristotle’s “problem of katholou ” in order to distinguish it from the “problem of universals” which is traditionally framed as the problem about the ontological status of universals. Aristotle coins the term katholou (traditionally translated as “universal”) and defines it as “that which is by nature predicated of many things". Yet, the traditional focus on the ontological status of universals is not Aristotle’s. His positive remarks about universals remain neutral with regard to their ontological status and escape the standard divide of realism and nominalism. I start with Aristotle’s neutrality and focus on …


Structural Insights Into Dna Replication And Lesion Bypass By Y Family Dna Polymerases, Kevin N. Kirouac Dec 2010

Structural Insights Into Dna Replication And Lesion Bypass By Y Family Dna Polymerases, Kevin N. Kirouac

Electronic Thesis and Dissertation Repository

Y family DNA polymerases are specialized enzymes for replication through sites of DNA damage in the genome. Although the DNA damage bypass activity of these enzymes is important for genome maintenance and integrity, it is also responsible for DNA mutagenesis due to the error-prone nature of the Y family. Understanding how these enzymes select incoming nucleotides during DNA replication will give insight into their role in cancer formation, aging, and evolution. This work attempts to mechanistically explain, primarily through X-ray crystallography and enzymatic activity assays, how Y family polymerases select incoming nucleotides in various DNA replication contexts. Initially, we sought …


Regulation Of Akt And Wnt Signalling By The Dopamine D2 Receptor And Metabotropic Glutamate Receptor 2/3, Laurie P. Sutton Dec 2010

Regulation Of Akt And Wnt Signalling By The Dopamine D2 Receptor And Metabotropic Glutamate Receptor 2/3, Laurie P. Sutton

Electronic Thesis and Dissertation Repository

Akt and the Wnt pathway, two cascades that regulate GSK-3, have been implicated in schizophrenia and antipsychotic drug action. Although it is known that antipsychotic drugs alleviate psychosis by blocking the dopamine D2 receptor (D2DR) and that metabotropic glutamate receptor 2/3 (mGluR2/3) agonists may improve some of the symptoms of schizophrenia, it is unclear if both classes of drugs exert their effects through Akt, GSK-3 and/or the Wnt pathway or if changes in these pathways are mediated through the D2DR and mGluR2/3 respectively. In addition to antipsychotics, mood stabilizers and antidepressants also target GSK-3, suggesting that there must be something …


The Evolution Of The Retail Landscape, Mathew Novak Dec 2010

The Evolution Of The Retail Landscape, Mathew Novak

Electronic Thesis and Dissertation Repository

If the city is a theatre of social interaction (Mumford 1996), then one of the principle stage sets is the retail landscape. Retail districts are generally where people congregate, making places of shopping among the liveliest areas the city. In addition to being social settings, retail areas are also where a large component of the city’s economy is transacted, and they are implicated in the political dramas of the city, particularly those dealing with issues of growth and development. Retail shops are highly visible elements of the urban landscape, lining principle arteries and clustering at major transit nodes. Retailing is …


Social Determinants Of Mental Health And Well-Being Among Aboriginal Peoples In Canada, Susan Wingert Dec 2010

Social Determinants Of Mental Health And Well-Being Among Aboriginal Peoples In Canada, Susan Wingert

Electronic Thesis and Dissertation Repository

The articles in this volume address the question: How do social determinants structure the health and well-being of the Aboriginal population in Canada? The first article uses bivariate statistical tests to assess whether First Nations residents’ subjective assessments of personal and community well-being correspond to scores from the Community Well-Being (CWB) Index, which is a measure of socioeconomic conditions in the community. The second article uses path analysis to test the extent to which the stress process model explains the social distribution of psychological distress and well-being in the off-reserve Aboriginal population. Specifically, it investigates whether stress, mastery, and social …


This Tract Of Land: North Buxton, Ontario, 1873-1914, Claudine Y. Bonner Dec 2010

This Tract Of Land: North Buxton, Ontario, 1873-1914, Claudine Y. Bonner

Electronic Thesis and Dissertation Repository

Acknowledging the continued concerns and calls for the education system to improve how it addresses the changing face of Canada in terms of race, gender, class, language and culture, this thesis focuses on the history and narratives of a single African-Canadian community as a starting point for educators who wish to learn about and make use of marginalized histories in their classroom practice. The information would also prove helpful to those educators who often have difficulty in finding material relating to African-Canadian history and as a result fail to add the stories of black Canadians to the national narrative shared …


Cardiac Adaptation To Chronic Blockade Of Voltage-Gated, L-Type Calcium Channels In The Sarcolemma, Ji Zhou Dec 2010

Cardiac Adaptation To Chronic Blockade Of Voltage-Gated, L-Type Calcium Channels In The Sarcolemma, Ji Zhou

Electronic Thesis and Dissertation Repository

L-type Ca2+ channels (dihydropyridine receptors, DHPRs) in the sarcolemma are essential to cardiac excitation-contraction (E-C) coupling. Thus, Ca2+ influx through DHPRs upon cardiomyocyte excitation triggers Ca2+ release from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyRs) to initiate myofilament activation and muscle contraction. Muscle relaxation occurs upon sequestration of Ca2+ back into the SR lumen by sarco/endoplasmic reticulum calcium-ATPase (SERCA) in the SR. As a treatment option for hypertension, long-term use of DHPR blockers is associated with increased risk of heart failure; underlying mechanisms are unknown. This research used male Wistar rats treated with verapamil (subcutaneously, …


Peroxisome Proliferator-Activated Receptor -Β/Δ, -Γ Agonists And Resveratrol Modulate Hypoxia Induced Changes In Nuclear Receptor Activators Of Muscle Oxidative Metabolism, Timothy R.H. Regnault, Lin Zhao, Jacky S.S. Chiu, Stephanie K. Gottheil, Allison Foran, Siu Pok Yee Dec 2010

Peroxisome Proliferator-Activated Receptor -Β/Δ, -Γ Agonists And Resveratrol Modulate Hypoxia Induced Changes In Nuclear Receptor Activators Of Muscle Oxidative Metabolism, Timothy R.H. Regnault, Lin Zhao, Jacky S.S. Chiu, Stephanie K. Gottheil, Allison Foran, Siu Pok Yee

Paediatrics Publications

PPAR-α, PPAR-β, and PPAR-γ, and RXR in conjunction with PGC-1α and SIRT1, activate oxidative metabolism genes determining insulin sensitivity. In utero, hypoxia is commonly observed in Intrauterine Growth Restriction (IUGR), and reduced insulin sensitivity is often observed in these infants as adults. We sought to investigate how changes in oxygen tension might directly impact muscle PPAR regulation of oxidative genes. Following eight days in culture at 1 oxygen, C2C12 muscle myoblasts displayed a reduction of PGC-1α, PPAR-α, and RXR-α mRNA, as well as CPT-1b and UCP-2 mRNA. SIRT1 and PGC-1α protein was reduced, and PPAR-γ protein increased. The addition of …


Sympathetic Neural Activation: An Ordered Affair, Craig D. Steinback, Aryan Salmanpour, Toni Breskovic, Zeljko Dujic, J. Kevin Shoemaker Dec 2010

Sympathetic Neural Activation: An Ordered Affair, Craig D. Steinback, Aryan Salmanpour, Toni Breskovic, Zeljko Dujic, J. Kevin Shoemaker

Paediatrics Publications

Is there an ordered pattern in the recruitment of postganglionic sympathetic neurones? Using new multi-unit action potential detection and analysis techniques we sought to determine whether the activation of sympathetic vasomotor neurones during stress is governed by the size principle of recruitment. Multi-unit postganglionic sympathetic activity (fibular nerve) was collected from five male subjects at rest and during periods of elevated sympathetic stress (end-inspiratory apnoeas; 178 ± 37 s(mean ± S.D.)). Compared to baseline (0.24 ± 0.04 V), periods of elevated stress resulted in augmented sympathetic burst size (1.34 ± 0.38 V, P < 0.05). Increased burst size was directly related to both the number of action potentials within a multi-unit burst of postganglionic sympathetic activity (r= 0.88 ± 0.04, P < 0.001 in all subjects), and the amplitude of detected action potentials (r= 0.88 ± 0.06, P < 0.001 in all subjects). The recruitment of larger, otherwise silent, neurons accounted for approximately 74% of the increase in detected action potentials across burst sizes. Further, action potential conduction velocities (inverse of latencies) were increased as a function of action potential size (R2= 0.936, P= 0.001). As axon diameter is positively correlated with action potential size and conduction velocity, these data suggest that the principle of ordered recruitment based on neuronal size applies to postganglionic sympathetic vasomotor neurones. This information may be pertinent to our understanding of reflex-specific recruitment strategies in postganglionic sympathetic nerves, patterns of vasomotor control during stress, and the malleability of sympathetic neuronal properties and recruitment in health and disease.The sympathetic nervous system is an important controller of blood pressure and blood flow to critical tissues and organs. In other neural systems (e.g. the skeletal motor system) there is a well understood pattern of neural recruitment during activation. Alternatively, our understanding of how sympathetic neurones are coordinated during stress is limited. We demonstrate that during stress otherwise silent sympathetic neurones are activated in an order based on neuronal size (from smallest to largest). This recruitment pattern is similar to what is known in other neural systems. This information has important implications for how blood pressure and blood flow are controlled, and the malleability of sympathetic activation in health and disease. © 2010 The Authors. Journal compilation © 2010 The Physiological Society.


The Dopamine D2 Receptor Gene And Depressive And Anxious Symptoms In Childhood: Associations And Evidence For Gene-Environment Correlation And Gene-Environment Interaction, Elizabeth P. Hayden, Daniel N. Klein, Lea R. Dougherty, Thomas M. Olino, Rebecca S. Laptook, Margaret W. Dyson, Sara J. Bufferd, C. Emily Durbin, Haroon I. Comardelle, Sinead Currie, Caitlin Denton, Cheryce L. Harrison, Tayla Lamerton, Gabriela P. Mena, Lisa Moran, Michelle Mottola, Taniya S. Nagpal, Lisa Vincze, Stephanie Schoeppe Dec 2010

The Dopamine D2 Receptor Gene And Depressive And Anxious Symptoms In Childhood: Associations And Evidence For Gene-Environment Correlation And Gene-Environment Interaction, Elizabeth P. Hayden, Daniel N. Klein, Lea R. Dougherty, Thomas M. Olino, Rebecca S. Laptook, Margaret W. Dyson, Sara J. Bufferd, C. Emily Durbin, Haroon I. Comardelle, Sinead Currie, Caitlin Denton, Cheryce L. Harrison, Tayla Lamerton, Gabriela P. Mena, Lisa Moran, Michelle Mottola, Taniya S. Nagpal, Lisa Vincze, Stephanie Schoeppe

Paediatrics Publications

ObjectiveS: Research implicates the A1 allele of the dopamine D2 receptor gene (DRD2) Taq1A polymorphism in the development of depression and anxiety. Furthermore, recent papers suggest that children with A1 allele of this gene may receive less positive parenting, and that the effects of this gene on child symptoms may be moderated by parenting. We sought to replicate and extend these findings using behavioral measures in a nonclinical sample of young children. Methods: In a sample of 473 preschool-aged children and their mothers, structured clinical interview measures and maternal reports of child symptoms were collected, and standardized observations of parent-child …