Physical activity (PA) must be performed regularly to accrue health benefits. However, the majority of manual wheelchair users do not meet PA recommendations. Existing community-based PA programs for manual wheelchair users appear to work, but effect sizes are small and retention is low. Existing PA programs may not fully implement some psychosocial factors that are strongly linked with PA (eg, autonomy). The use of peers and mobile phone technology in the Smartphone Peer PA Counseling (SPPAC) program represents a novel approach to cultivating a PA-supportive environment for manual wheelchair users., Peer-reviewed article, Published.
A study was conducted to review the acoustical features and the potential contributions of green roofs to the acoustical environment, to investigate sound transmission theory, and to report on new empirical findings on the transmission loss of green roofs. The results of the study shows that existing sound transmission algorithms do not adequately predict TL of light-weight roof system or green roofs, nor describe the potential effect of moisture content of the substrate. The sound energy is dissipated in the substrate and provides a mass loading and damping effect on to the light-weight roof deck. The study also suggested that green roofs will provide a higher TL than the additional ceiling element and improve TL throughout the full architectural frequency range, specifically desirable in residential and institutional occupancies that are developed below aircraft flight paths., Article, Published.
During embryonic development, the positional information provided by concentration gradients of maternal factors directs pattern formation by providing spatially dependent cues for gene expression. In the fruit fly, Drosophila melanogaster, a classic example of this is the sharp on-off activation of the hunchback (hb) gene at midembryo, in response to local concentrations of the smooth anterior-posterior Bicoid (Bcd) gradient. The regulatory region for hb contains multiple binding sites for the Bcd protein as well as multiple binding sites for the Hb protein. Some previous studies have suggested that Bcd is sufficient for properly sharpened Hb expression, yet other evidence suggests a need for additional regulation. We experimentally quantified the dynamics of hb gene expression in flies that were wild-type, were mutant for hb self-regulation or Bcd binding, or contained an artificial promoter construct consisting of six Bcd and two Hb sites. In addition to these experiments, we developed a reaction-diffusion model of hb transcription, with Bcd cooperative binding and hb self-regulation, and used Zero Eigenvalue Analysis to look for multiple stationary states in the reaction network. Our model reproduces the hb developmental dynamics and correctly predicts the mutant patterns. Analysis of our model indicates that the Hb sharpness can be produced by spatial bistability, in which hb self-regulation produces two stable levels of expression. In the absence of self-regulation, the bistable behavior vanishes and Hb sharpness is disrupted. Bcd cooperative binding affects the position where bistability occurs but is not itself sufficient for a sharp Hb pattern. Our results show that the control of Hb sharpness and positioning, by hb self-regulation and Bcd cooperativity, respectively, are separate processes that can be altered independently. Our model, which matches the changes in Hb position and sharpness observed in different experiments, provides a theoretical framework for understanding the data and in particular indicates that spatial bistability can play a central role in threshold-dependent reading mechanisms of positional information., Peer-reviewed article, Published. Received October 16, 2007; Accepted August 13, 2008; Published September 26, 2008.
Proceedings of the 18th IEEE Symposium on Logic in Computer Science (LICS-03), Ottawa, ON, 2003. The spectrum of a first-order sentence is the set of cardinalities of its finite models. Relatively little is known about the subclasses of spectra that are obtained by looking only at sentences with a specific signature. In this paper, we study natural subclasses of spectra and their closure properties under simple subdiagonal functions. We show that many natural closure properties turn out to be equivalent to the collapse of potential spectrum hierarchies. We prove all of our results using explicit transformations on first-order structures., Conference paper, Published.
Objective: The objective of this study was to evaluate the association between spinal cord injury (SCI) and type 2 diabetes in a large representative sample and to determine whether an association exists irrespective of known risk factors for type 2 diabetes. Methods: Data were obtained on 60,678 respondents to the Statistics Canada 2010 Cycle of the cross-sectional Canadian Community Health Survey. Multivariable logistic regression, incorporating adjustment for confounders and probability weights to account for the Canadian Community Health Survey sampling method, was conducted to quantify this association. Results: After adjustment for both sex and age, SCI was associated with a significant increased odds of type 2 diabetes (adjusted odds ratio = 1.66, 95% confidence interval 1.16–2.36). These heightened odds persisted after additional adjustment for smoking status, hypertension status, body mass index, daily physical activity, alcohol intake, and daily consumption of fruits and vegetables (fully adjusted odds ratio = 2.45, 95% confidence interval 1.34–4.47). Conclusions: There is a strong association between SCI and type 2 diabetes, which is not explained by known risk factors for type 2 diabetes., Peer-reviewed article, Published. Received May 14, 2013 ; Accepted August 21, 2013.
Study Design: Secure, web-based survey. Objectives: Elicit specific information about sexual function from women with spinal cord injuries (SCI). Setting: World-wide web. Methods: Individuals 18 years or older living with SCI obtained a pass code to enter a secure website and then answered survey questions. Results: Bladder and/or bowel incontinence during sexual activity and/or sexual intercourse were significant concerns and prevented some women from seeking sexual activity. Autonomic dysreflexia (AD) during sexual activity was interpreted negatively by many and was found to interfere with sexual activity. Most subjects reported difficulty becoming psychologically aroused as well as physically aroused, which were both correlated with feeling that their SCI had altered their sexual sense of self. An inverse relationship existed between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. The most commonly reported sexual stimulation leading to the best arousal involved stimulation of the head/neck and torso areas. The majority of subjects reported having experienced intercourse postinjury. Most participants reported difficulty with positioning during foreplay and intercourse, vaginal lubrication, and spasticity during intercourse. Almost half reported experiencing orgasm postinjury and this was positively associated with the presence of genital sensation. Conclusion: SCI significantly impairs psychological and physical aspects of female sexual arousal. In addition, bladder and bowel incontinence as well as AD negatively impact sexual activity and intercourse., Peer-reviewed article, Published.
Thee aim of this chapter is to provide the reader with a general overview of the different phenomena and factors involved with durability of repair and suggest the major aspects which the repair design should focus on. However, it is important to keep in mind that any repair problem needs to be addressed as a unique problem ﬁrst, and the designer, by developing awareness of the several challenges involved, should be able to make mindful choices, adequate to the specific application that is being considered., Book chapter, Published.
Proceedings of 2017 International Conference on Noise and Fluctuations (ICNF), Vilnius, Lithuania on 20-23 June 2017. Segmentation of the developing insect body is preceded by cell-specific gene expression. In fruit flies (Drosophila), pair-rule genes are expressed in spatial stripes specifying segment fates. Transcription of the even-skipped (eve) pair-rule gene was recently shown to proceed in noisy bursts. Here, we develop a stochastic model of eve transcription from DNA to mRNA. This indicates that eve transcription proceeds at two rates, with a slow rate providing basal production and a fast rate allowing for high mRNA output. This two-rate transcription may afford more reliability in mRNA output, and therefore the protein levels which specify cell type, than a simple on-off (one-rate) mechanism., Conference paper, Published.
This work looks at the impact of assumptions made regarding efficiency of storage systems used with variable energy resources and how this applies to a solar PV installation. To find the optimal storage system to work with the cyclic solar output, a linear optimization model is implemented using OSeMOSYS. With 100% efficient, free storage, with no capacity restrictions, it is possible to get down to almost 5 GW of required solar installed capacity, but it requires 1.1 TWh of 100% efficient storage. Existing pumped hydro storage facilities have efficiencies between 70 and 80%, which increase these numbers to 7 GW and 1.2 TWh. With a storage model based on the worlds largest pumped hydro facility between 20 and 25 GW of installed solar capacity are required plus between 15 and 30 GWh of storage capacity to meet the 1 GW load. The capital infrastructure required to allow a solar installation to meet that of a baseload plant is therefore around an order of magnitude larger than what is commonly assumed. A shift away from fossil fuels to renewable/variable energy resources will require more infrastructure than indicated by simply considering the capacity factor of the energy source., Peer-reviewed article, Published. Manuscript received September 30, 2014; revised January 18, 2015.
The use of Fibre Reinforced Polymers (FRP) has grown in popularity in the construction industry. FRP has proven useful in the retrofit of various types of structural elements. It may be used for the strengthening of beams, the seismic upgrade of walls panels, as well as the jacketing of columns to provide confinement. There exist several methods of FRP application for the case of structural retrofits. These include the application of pre-prepared FRP mats, or application of FRP via the wet lay-up process. However, a new technique developed at the University of British Columbia allows for the application of FRP in the form of a spray. Externally bonded Sprayed FRP (SFRP) is known to increase strength and energy absorption capacity of a retrofitted member as well as, or better than, FRP sheets. However, tests have primarily been carried out on concrete members only. An area of interest, into which not much research has been conducted, is the application of SFRP to timber. Timber bridges are extensively used in many parts of the world. Often due to remoteness and practical constraints, it is impossible to apply FRP sheets to retrofit these bridges. SFRP would be a much easier method of FRP application. This study looked at the application of SFRP to Douglas Fir (D.Fir) Beam specimens subjected to 3-Point Flexural Loading only. The specimens were treated with either a water based (Borocol) or oil borne (Creosote) antifungal preservative prior to being sprayed with FRP. Different combinations of adhesives/bonding agents including Hydroxymethylated Resorcinol and Polymeric Isocyanates were used to try to develop a strong bond. When considering using only chemical adhesives to obtain a proper bond between the two constituents of the composite, use of HMR is recommended for timber which is untreated or has been treated with a water borne preservative such as Borocol, while a pMDI adhesive such as AtPrime 2 is recommended for timber treated with an oil borne preservative such as Creosote. For Non Creosoted beams, adhesives did not generate as significant of a strength gain. For Creosoted beams, adhesives may be sufficient to generate significant strength gain when SFRP is applied to a beam. Considering that most structures in use would probably have been treated with a preservative similar to Creosote, in practice, AtPrime 2 or some other some sort of pMDI would probably be the adhesive of choice. Based on the results of the study, it is possible to say that the application of SFRP to retrofit/rehabilitate timber structures shows considerable promise. If a decent bond is achieved between the composite constituents, it is possible to substantially increase the ultimate flexural strength of the member, as well as drastically increase its ductility and energy absorption capacity. It is recommended that further tests be carried out using different types of loading schemes, geometrical configurations of SFRP, other types of anchorage, and development of a proper analytical model before the method is adopted for widespread use., Thesis, Published.
Proceedings of 2012 European Intelligence and Security Informatics Conference (EISIC) in Odense, Denmark 22-24 Aug. 2012. Much of the information exchanged between agents over a network is encapsulated in XML documents. An XML document has a tree structure, and the meaning of the document can be understood in terms of a set of label-value pairs. The content of a document is often secured through digital signatures applied to different sections, while the document is passed between several agents. In this paper, we illustrate that this process is insecure in the sense that a malicious agent can deceive an honest agent to hold beliefs that are untrue. We provide a formal framework for analyzing the security of structured documents, based on the implicit epistemic impact that a signed document will have on a recipient. This kind of analysis can provide significant insight into deception and fraud detection., Conference paper, Published.
Proceedings of 2013 Humaine Association Conference on Affective Computing and Intelligent Interaction, Geneva, Switzerland, 2-5 Sept. 2013. We present the results of a study that explored the emotions experienced by students during interaction with an educational game for math (Heroes of Math Island). Starting from emotion frameworks in affective computing and education, we considered a larger set of emotions than in related research. For emotion labeling, we employed a standard method that relies on trained judges to report emotions over 20-second intervals. However, we asked judges to report all observed emotions in each interval, as opposed to only choosing one, as is standard practice. This variation allows us to discuss the appropriateness of this interval for emotion labeling. We present a detailed analysis of inter-coder reliability, both aggregated and over individual students, that considers not only the matching by judges over emotion type, but also the number of emotions detected., Conference paper, Published., Peer reviewed