The oligosaccharide β-d-Galf-(1→3)-α-d-Manp-(1→2)-[β-d-Galf-(1→3)]-α-d-Manp-(1→2)-α-d-Manp corresponds to the terminal end of the glycosylinositolphospholipid oligosaccharide of the protozoan Trypanosomacruzi, the causative agent of Chagas’ disease. Syntheses of methyl or ethylthio glycosides of the terminal disaccharide, trisaccharide, tetrasaccharide, and pentasaccharide corresponding to this structure are described. These syntheses employ the selective activation of a phenyl 1-selenogalactofuranoside or a phenyl 1-selenomannopyranoside donor over ethyl 1-thioglycoside acceptors with NIS–TfOH., Peer-reviewed article, Published. Received 8 December 1999; Accepted 14 December 1999; Available online 19 April 2000.
Proceedings from the 23rd Annual ACM Conference on Innovation and Technology in Computer Science Education. Since computing education began, we have sought to learn why students struggle in computer science and how to identify these at-risk students as early as possible. Due to the increasing availability of instrumented coding tools in introductory CS courses, the amount of direct observational data of student working patterns has increased significantly in the past decade, leading to a flurry of attempts to identify at-risk students using data mining techniques on code artifacts. The goal of this work is to produce a systematic literature review to describe the breadth of work being done on the identification of at-risk students in computing courses. In addition to the review itself, which will summarize key areas of work being completed in the field, we will present a taxonomy (based on data sources, methods, and contexts) to classify work in the area., Peer reviewed, Conference paper, Published.
Understanding temperature and airflow patterns in an attic roof helps to identify the sections of the roof where moisture damage and roofing material durability problems can be expected. In this paper, the temperature distribution and the airflow patterns inside an attic space in a climate that can be characterized with cold winter and hot summer periods are discussed. In the study, transient boundary conditions were applied, and the dynamic responses of a typical attic roof, including the flow patterns, attic air and roof sheathing temperatures, ventilation rates, and heating and cooling loads, are presented. These findings can be used to understand the airflow pattern and how it can be affected by an incoming wind speed and solar gain., Peer reviewed article, Published. Received: September 14, 2016; Accepted: March 08, 2017; Published online: June 22, 2017.
14th Canadian Conference on Building Science and Technology, Toronto, Canada, October 29th-30th, 2014.
It is essential to design and operate buildings with good indoor air quality as people spend most of their time indoor. Their productivity, comfort and health depend on the quality of the indoor air. In addition to other air quality parameters, indoor humidity and temperature need to be controlled and maintained to acceptable ranges. These conditions may not be uniform within the house/building due to local heat and moisture sources and absence of an effective indoor air mixing mechanism as in the case of in buildings with baseboard heating systems. Localized high humidity creates favourable conditions for localized mold growth, poor indoor air quality and building envelope damage. In this paper, the indoor humidity and temperature distributions within four suites (designated as Suite ‘A’, ‘B’, ‘C’ and ‘D’) in a six-storey multi-residential building are studied. A total of 22 rooms are monitored with indoor temperature and relative humidity data loggers, and the outdoor climatic conditions are measured with a weather station for over a year. The hygrothermal performances of exterior walls in the master bedrooms of the respective suites are assessed. Analysis of the measured data suggests that the temperature variations between the rooms (bedrooms, living room, kitchen excluding bathroom) are relatively low during the summer period (mean temperature difference less than 1oC) compared to the winter period where the variations between the rooms can be as high as 2oC. The excess humidity differences between the rooms, excluding the kitchens, are in the range of 0.2 g/m 3 to 1.0 g/m 3 during both winter and summer periods, whereas the excess humidity fluctuations within the rooms are fairly the same and have standard deviation values between 0.8 g/m 3 and 1.0 g/m 3. Excess humidity is defined as the difference between the indoor and outdoor absolute humidities, quantities that
are derived from the simultaneously measured temperature and relative humidity of the indoor and outdoor locations. Hygrothermal simulation results of exterior wall systems indicate that, in a mild coastal climate, the winter average indoor relative humidity shall be below 43% (for a seasonal average indoor temperature of 20oC) to avoid building envelope moisture damage., Peer reviewed article, Published.
Meeting and exceeding requirements for indoor air quality, thermal comfort, and acoustic and visual quality can lead to optimized environments that maximize well-being and performance. However, surveys on numerous buildings have revealed that satisfactory indoor environmental conditions are often not achieved. This suggests the whole industry needs more systematic methods to analyze and design indoor environments., Peer reviewed, Technical feature, Published 2018., Thermal comfort, Thermal environmental quality, ASHRAE Standard 55-2017
Proceedings of Building Physics Symposium: 29 October 2008, Leuven, Belgium.
This paper describes the use of a whole building hygrothermal model (HAMFitPlus) to analyze the energy savings resulting from three programmable thermostat setting schemes in a real occupied residential house. It discusses the effect of these schemes on the indoor relative humidity and moisture performance. In the first thermostat-setting scheme, the indoor temperature is maintained constant at 21 at all time (no set-back). In the second thermostat-setting scheme, the indoor temperature is maintained at 21ºC from 7:00 to 21:00 h, and then setback to 17ºC for the remaining hours (21:00 to 7:00 h)., Conference paper, Published. A version of this document is published in: Building Physics Symposium, Lueven, Belgium, October 29-31, 2008, pp. 1-5.
Anterior-posterior (AP) body segmentation of the fruit fly (Drosophila) is first seen in the 7-stripe spatial expression patterns of the pair-rule genes, which regulate downstream genes determining specific segment identities. Regulation of pair-rule expression has been extensively studied for the even-skipped (eve) gene. Recent live imaging, of a reporter for the 2nd eve stripe, has demonstrated the stochastic nature of this process, with ‘bursts’ in the number of RNA transcripts being made over time. We developed a stochastic model of the spatial and temporal expression of eve stripe 2 (binding by transcriptional activators (Bicoid and Hunchback proteins) and repressors (Giant and Krüppel proteins), transcriptional initiation and termination; with all rate parameters constrained by features of the experimental data) in order to analyze the noisy experimental time series and test hypotheses for how eve transcription is regulated. These include whether eve transcription is simply OFF or ON, with a single ON rate, or whether it proceeds by a more complex mechanism, with multiple ON rates. We find that both mechanisms can produce long (multi-minute) RNA bursts, but that the short-time (minute-to-minute) statistics of the data is indicative of eve being transcribed with at least two distinct ON rates, consistent with data on the joint activation of eve by Bicoid and Hunchback. We also predict distinct statistical signatures for cases in which eve is repressed (e.g. along the edges of the stripe) vs. cases in which activation is reduced (e.g. by mutagenesis of transcription factor binding sites). Fundamental developmental processes such as gene transcription are intrinsically noisy; our approach presents a new way to quantify and analyze time series data during developmental patterning in order to understand regulatory mechanisms and how they propagate noise and impact embryonic robustness., Peer-reviewed article, Published. Received: November 21, 2016; Accepted: April 8, 2017; Published: April 24, 2017.
Most building materials are porous, composed of solid matrix and pores. The time varying indoor and outdoor climatic conditions result heat, air and moisture (HAM) transfer across building enclosures. In this paper, a transient model that solves the coupled heat, air and moisture transfer through multilayered porous media is developed and benchmarked using internationally published analytical, numerical and experimental test cases. The good agreements obtained with the respective test cases suggest that the model can be used to assess the hygrothermal performance of building envelope components as well as to simulate the dynamic moisture absorption and release of moisture buffering materials., Peer reviewed article, Published. Received 26 February 2009, Revised 30 September 2009, Accepted 1 October 2009, Available online 13 April 2010.
Douglas-fir heartwood thermomechanical pulp was treated with laccase enzymes at 25 and 50°C with and without added oxygen. The treated pulps were cleached with hudrogen peroxide at increasing alkali charges. Laccase treatments without added oxygen increased bleached brightness by 1.5-2.5 pts ISO, and decreased hydrogen peroxide consumption by 15-20%. The enzyme treatments were not enhanced when supplemented with oxygen. When the effectiveness of four different laccase enzymes was compared for the treatment of Douglas-fir heartwood thermomechanical pulp, there were no significant differences found in the performance among the enzymes. Possible explanations for the observed results are given., Peer-reviewed article, Published.
Belief revision is concerned with incorporating new information into a pre-existing set of beliefs. When the new information comes from another agent, we must first determine if that agent should be trusted. In this paper, we define trust as a pre-processing step before revision. We emphasize that trust in an agent is often restricted to a particular domain of expertise. We demonstrate that this form of trust can be captured by associating a state partition with each agent, then relativizing all reports to this partition before revising. We position the resulting family of trust-sensitive revision operators within the class of selective revision operators of Ferme and Hansson, and we prove a representation result that characterizes the class of trust-sensitive revision operators in terms of a set of postulates. We also show that trust-sensitive revision is manipulable, in the sense that agents can sometimes have incentive to pass on misleading information., Article, Published.
Proceedings of the Twenty-Fourth International Joint Conference on Artificial Intelligence in Buenos Aires, Argentina, 25–31 July 2015. Belief revision is concerned with incorporating new information into a pre-existing set of beliefs. When the new information comes from another agent, we must first determine if that agent should be trusted. In this paper, we define trust as a pre-processing step before revision. We emphasize that trust in an agent is often restricted to a particular domain of expertise. We demonstrate that this form of trust can be captured by associating a state partition with each agent, then relativizing all reports to this partition before revising. We position the resulting family of trust-sensitive revision operators within the class of selective revision operators of Ferme and Hansson, and we examine its properties. In particular, we show how trust-sensitive revision is manipulable, in the sense that agents can sometimes have incentive to pass on misleading information. When multiple reporting agents are involved, we use a distance function over states to represent differing degrees of trust; this ensures that the most trusted reports will be believed., Conference paper, Published.