Student perceptions of model-based estimating

The use of building information modeling (BIM) is well established in architecture, engineering and construction. However, previous studies note a lack of BIM expertise in academia, leading to slow adoption and limited knowledge on which to base BIM-related content. To improve course development, it is important to understand students’ perceptions of BIM-related subject matter. This study exposed estimating students (n = 214) to a model-based quantity takeoff (QTO) tutorial using Revit. Students’ perceptions of a Revit-based BIM’s usefulness for easily providing reliable and accurate material quantities were measured using a pre-test, tutorial and post-test design. Results revealed significant differences in students’ mean levels of agreement that an accurate QTO is completed for an estimator with the click of a button when a design team generated BIM model is available. Results also revealed significant differences in students’ level of agreement that a Revit-based BIM makes performing QTO by hand obsolete. This study provides educators’ insight into students’ perceptions of BIM use in QTO. Understanding student perceptions is paramount for construction management educators when designing a course and attempting to convey the value of foundational estimating skills while acknowledging the existence of more technologically advance estimating methods. Limitations and opportunities for further research are discussed.     

Optimal strategies to protect a sub-population at risk due to an established epidemic

Epidemics can particularly threaten certain sub-populations. For example, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the elderly are often preferentially protected. For diseases of plants and animals, certain sub-populations can drive mitigation because they are intrinsically more valuable for ecological, economic, socio-cultural or political reasons. Here, we use optimal control theory to identify strategies to optimally protect a ‘high-value’ sub-population when there is a limited budget and epidemiological uncertainty. We use protection of the Redwood National Park in California in the face of the large ongoing state-wide epidemic of sudden oak death (caused by Phytophthora ramorum) as a case study. We concentrate on whether control should be focused entirely within the National Park itself, or whether treatment of the growing epidemic in the surrounding ‘buffer region’ can instead be more profitable. We find that, depending on rates of infection and the size of the ongoing epidemic, focusing control on the high-value region is often optimal. However, priority should sometimes switch from the buffer region to the high-value region only as the local outbreak grows. We characterize how the timing of any switch depends on epidemiological and logistic parameters, and test robustness to systematic misspecification of these factors due to imperfect prior knowledge.     

Promoting CM Student Success: Establishing an Academic Performance Benchmark Given Construction-Education Self-Efficacy,Motivation and Planned Behavior

High levels of self-efficacy, motivation and intentions to perform well are necessary to achieve high grade point averages (GPA) in demanding academic programs including engineering, mathematics and the sciences. However, scant research has investigated these constructs within the domain of construction management (CM) education. The Construction Training Attitudes and Intentions Scale (CTAIS), which adapts self-efficacy, motivation and planned behavior constructs to the construction-education domain, was administered among CM and Non-CM students (n = 633) enrolled in courses required for a bachelor degree at three American Council for Construction Education accredited programs. Significant differences (p < .001) in construction-education domain-level constructs were observed for CM and Non-CM majors providing evidence of face validity. CM majors (n = 587) were separated for ANOVA. Significant differences in self-efficacy (p = .014) and planned behavior (p = .001) were observed by GPA. Post-hoc analysis revealed differences in these constructs based on GPA above, or below, 3.0. CM majors (n = 587) were aggregated using the 3.0 GPA benchmark (GPA > 3.0, n = 328; GPA< 3.0, n = 239). T-test results revealed significantly higher levels of self-efficacy (p = .001) and planned behavior (p < .001) among students with GPAs above 3.0. This study provides CM educators with a domain-specific measure to target students for interventions that promote success. Limitations and opportunities for further research are discussed.     

Extracellular Matrix Deposition and Remodeling after Corneal Alkali Burn in Mice

Corneal transparency relies on the precise arrangement and orientation of collagen fibrils, made of mostly Type I and V collagen fibrils and proteoglycans (PGs). PGs are essential for correct collagen fibrillogenesis and maintaining corneal homeostasis. We investigated the spatial and temporal distribution of glycosaminoglycans (GAGs) and PGs after a chemical injury. The chemical composition of chondroitin sulfate (CS)/dermatan sulfate (DS) and heparan sulfate (HS) were characterized in mouse corneas 5 and 14 days after alkali burn (AB), and compared to uninjured corneas. The expression profile and corneal distribution of CS/DSPGs and keratan sulfate (KS) PGs were also analyzed. We found a significant overall increase in CS after AB, with an increase in sulfated forms of CS and a decrease in lesser sulfated forms of CS. Expression of the CSPGs biglycan and versican was increased after AB, while decorin expression was decreased. We also found an increase in KS expression 14 days after AB, with an increase in lumican and mimecan expression, and a decrease in keratocan expression. No significant changes in HS composition were noted after AB. Taken together, our study reveals significant changes in the composition of the extracellular matrix following a corneal chemical injury.     

Evolution of supramolecular healable composites: a minireview

Efforts to further extend the range of applications of polymer based materials have resulted in the recent production of healable polymers that can regain their strength after damage. Within this field of healable materials, supramolecular polymers have been subject to extensive investigation. By virtue of their reversible non‐covalent interactions, cracks and fractures in such polymers can be readily and repeatedly healed in order to regain key physical properties. However, many supramolecular polymers are relatively weak and elastomeric in nature, which renders them unsuitable for high strength structural applications. To overcome these deficiencies, preliminary studies have shown that it is possible to reinforce supramolecular polymers with microscale and nanoscale fillers to afford composites that are not only stronger and stiffer compared with the polymers alone but also retain their healing abilities. In this minireview we discuss the evolution of these supramolecular composites and their advantages over more conventional, covalent polymeric materials. © 2014 Society of Chemical Industry     

The effects and perceived consequences of testing accommodations on math and science performance assessments.

The present study examined the effect accommodations have on test results of students with and without disabilities and documented experts’ judgments about the appropriateness of testing accommodations. Test score data were collected from 218 fourth-grade students with and without disabilities on mathematics and science performance tasks and from eight testing experts who evaluated the fairness and validity of a sample of testing accommodations used with these students. Results indicated that, for most students with disabilities and some students without disabilities, packages of testing accommodations had a moderate to large effect on performance task scores. Expert reviewers rated most accommodations for a student with disabilities as being both valid and fair, and they gave accommodations listed on a student’s individualized education program (IEP) significantly higher validity and fairness ratings than accommodations that were not listed on the student’s IEP. Interpretations of these data are provided and implications for practice and future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of risk-informed design methods to select the PSACS ultimate heat sink

In the early phases of advanced system design, information is scarce. The technologies, components and processes to be used have not been specified adequately or are not well understood and uncertainties are very large. Yet, it is during these early phases that design teams and other stakeholders are required to make critical decisions to guide the development of the system. To aid in this decision making, a formal process is proposed based on the Analytic-Deliberative Decision-Making Process (ADP) that allows stakeholders to synthesize rationally their knowledge and experience and facilitate learning and sharing of best practices. The ADP identifies and prioritizes attributes relevant to a decision problem and supports the formulation of metrics to measure the performance of different design options. This paper reports on an application of the ADP to the selection of an ultimate heat sink for the Flexible Conversion Ratio (FCR) reactor's Passive Secondary Auxiliary Cooling System (PSACS). Two ultimate heat sink options are identified and evaluated, air and water.