Slip modulus of cold-formed steel members sheathed with wood structural panels

Maher, J. E., & Kramer, K. W. (2007). LEED-NC version 2.2 rating system applications of common structural materials. Paper presented at the Sustainable Construction Materials and Technologies - International Conference on Sustainable Construction Materials and Technologies, 549-562.Cold-formed steel framing sheathed with wood structural panels is a common method of construction for wall, roof and floor systems in cold-formed steel structures. Since wood structural panels are attached with screws at relatively close spacing, a certain amount of composite behavior will be present. The benefit of composite behavior is not currently being taken advantage of in the design of these structural systems. While composite effects are present, they are not yet being accounted for in design due to a lack of statistical data. To determine the amount of composite action taking place in these systems, the slip modulus between steel and wood is required. The slip modulus reflects the amount of shear force able to be transferred through the screw connection, to either member of the composite system. This paper presents the results of a study conducted to determine values of the slip modulus for varying thicknesses of cold-formed steel and plywood sheathing. Shear tests were conducted and the slip moduli were determined based on ISO 6891 and ASTM D1761. Compared with data from a previous preliminary study performed by others, the slip modulus values determined from these tests were deemed reasonable. The determination of the slip modulus will lead to the ability to calculate a composite factor. Determination of a composite factor will allow cold-formed steel wood structural panel construction to become more economical due to the available increase in bending strength

Ways of Being Smart in Engineering: Beliefs, Values, and Introductory Engineering Experiences

Common discourse conveys that to be an engineer, one must be “smart.” Our individual and collective beliefs about what constitutes smart behavior are shaped by our participation in the complex cultural practice of smartness. From the literature, we know that the criteria for being considered “smart” in our educational systems are biased. The emphasis on selecting and retaining only those who are deemed “smart enough” to be engineers perpetuates inequity in undergraduate engineering education. Less is known about what undergraduate students explicitly believe are the different ways of being smart in engineering or how those different ways of being a smart engineer are valued in introductory engineering classrooms. In this study, we explored the common beliefs of undergraduate engineering students regarding what it means to be smart in engineering. We also explored how the students personally valued those ways of being smart versus what they perceived as being valued in introductory engineering classrooms. Through our multi-phase, multi-method approach, we initially qualitatively characterized their beliefs into 11 different ways to be smart in engineering, based on a sample of 36 engineering students enrolled in first-year engineering courses. We then employed quantitative methods to uncover significant differences, with a 95% confidence interval, in six of the 11 ways of being smart between the values personally held by engineering students and what they perceived to be valued in their classrooms. Additionally, we qualitatively found that 1) students described grades as central to their classroom experience, 2) students described the classroom as a context where effortless achievement is associated with being smart, and 3) students described a lack of reward in the classroom for showing initiative and for considerations of social impact or helping others. As engineering educators strive to be more inclusive, it is essential to have a clear understanding and reflect on how students value different ways of being smart in engineering as well as consider how these values are embedded into teaching praxis

Experiences with the Streptococcus mutans in Lakota Sioux (SMILeS) Study: Risk Factors for Caries in American Indian Children 0-3 Years

Severe Early Childhood Caries (S-ECC) is a terribly aggressive and devastating disease that is all too common in lower socio-economic children, but none more so that what is encountered in American Indian Tribes. Nationwide, approximately 27% of 2-5 year olds have decay while 62% percent of American Indian/Alaska Native children in the same age group have a history of decay (IHS 2010, NHANES 1999-2002). We have conducted a study of children from birth to 36 months of age on Pine Reservation to gain a better understanding of the variables that come into play in the development of this disease, from transmission and acquisition of Streptococcus mutans genotypes from mother to child to multiple dietary and behavioral components. This article describes how we established a direct partnership with the Tribe and the many opportunities and challenges we faced in performing this 5-year field study

An Intervention to Promote Growth Mindset and STEM Self-Efficacy of High School Students: Exploring the Complexity of Beliefs

The marginalization of women in engineering is a persistent problem. The overall goal of our collaborative project was to promote interest and participation in science, technology, engineering, and mathematics (STEM), particularly for high school girls. We took an action research approach with a local high school science teacher to develop, implement, and research the impact of a classroom-based intervention designed to encourage growth mindset and STEM self-efficacy beliefs using mixed methods. We analyzed pre- and postsurvey data collected using a control-treatment design to determine the impact of the intervention on high school boys’ and girls’ self-efficacy and mindset beliefs. We also conducted semi-structured, one-on-one interviews with purposefully selected participants from the treatment group to further explore students’ mindset and STEM self-efficacy beliefs qualitatively. We found that the intervention did result in a statistically significant change towards more growth-oriented beliefs for the high school girls who received the intervention as compared to the control group. We found that the intervention did not result in any statistically significant change in the girls’ self-efficacy beliefs, the boys’ mindset beliefs, or the boys’ self-efficacy beliefs. The qualitative analysis revealed that after receiving the intervention, students held contradictory beliefs about the role of effort and the role of innate ability in STEM achievement. Further, we found that context and gender mattered in how students justified their self-efficacy: boys and girls both expressed the belief that effort would lead to their ability to succeed in science classes, but the girls were less likely than the boys to express the belief that effort would lead to their ability to succeed in the context of a science career. By connecting our findings to broader cultural narratives, we suggest that for the continued success of intervention efforts aimed at promoting a growth mindset and STEM self-efficacy, particularly for girls, such efforts should include opportunities for students to reflect upon and unpack the broader cultural narratives about effort, innate ability, and the gendered stereotypes about STEM ability that inform their beliefs. Finally, from the perspective of a high school science teacher, we also advocate for more representation of women among science teachers and classroom speakers and the importance of explicitly connecting class content and success in classrooms to real-world contexts

NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn

We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE dataset. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer Solar System, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.Comment: 17 pages, 3 figures, accepted for publication in Astrophysical Journa

Linguistic Biases in Letters of Recommendation Written for Rheumatology Fellowship Applicants

Our study aimed to investigate for implicit linguistic biases in letters of recommendation written for applicants applying to our rheumatology program, and to determine if differences in gender and race exist between the applicants. Additionally, we wanted to compare these results to the gender, race, academic rank, and position of the letter writers. We found that among the preliminary 50 letters, they showed that our letters seemed to show the opposite trends than other published studies. We anticipate the need for further study, and look forward to the results

The Millisecond Radio Sky: Transients from a Blind Single Pulse Search

We present the results of a search for transient radio bursts of between 0.125 and 32 millisecond duration in two archival pulsar surveys of intermediate galactic latitudes with the Parkes multibeam receiver. Fourteen new neutron stars have been discovered, seven of which belong to the recently identified "rotating radio transients" (RRATs) class. Here we describe our search methodology, and discuss the new detections in terms of how the RRAT population relates to the general population of pulsars. The new detections indicate (1) that the galactic z-distribution of RRATs in the surveys closely resembles the distribution of pulsars, with objects up to 0.86 kpc from the galactic plane; (2) where measurable, the RRAT pulse widths are similar to that of individual pulses from pulsars of similar period, implying a similar beaming fraction; and (3) our new detections span a variety of nulling fractions, and thus we postulate that the RRATs may simply be nulling pulsars that are only "on" for less than a pulse period. Finally, the newly discovered object PSR J0941-39 may represent a link between pulsars and RRATs. This bizarre object was discovered as an RRAT, but in follow-up observations often appeared as a bright (~10 mJy) pulsar with a low nulling fraction. It is obvious therefore that a neutron star can oscillate between being an RRAT and a pulsar. Crucially, the sites of the RRAT pulses are coincident with the pulsar's emission, implying that the two emission mechanisms are linked, and that RRATs are not just pulsars observed from different orientations.Comment: 13 pages, 9 figures, accepted by MNRA

A Time Series Analysis of Air Pollution and Preterm Birth in Pennsylvania, 1997–2001

Preterm delivery can lead to serious infant health outcomes, including death and lifelong disability. Small increases in preterm delivery risk in relation to spatial gradients of air pollution have been reported, but previous studies may have controlled inadequately for individual factors. Using a time-series analysis, which eliminates potential confounding by individual risk factors that do not change over short periods of time, we investigated the effect of ambient outdoor particulate matter with diameter ≤10 μm (PM(10)) and sulfur dioxide on risk for preterm delivery. Daily counts of preterm births were obtained from birth records in four Pennsylvania counties from 1997 through 2001. We observed increased risk for preterm delivery with exposure to average PM(10) and SO(2) in the 6 weeks before birth [respectively, relative risk (RR) = 1.07; 95% confidence interval (CI), 0.98–1.18 per 50 μg/m(3) increase; RR = 1.15; 95% CI, 1.00–1. 32 per 15 ppb increase], adjusting for long-term preterm delivery trends, co-pollutants, and offsetting by the number of gestations at risk. We also examined lags up to 7 days before the birth and found an acute effect of exposure to PM(10) 2 days and 5 days before birth (respectively, RR = 1.10; 95% CI, 1.00–1.21; RR = 1.07; 95% CI, 0.98–1.18) and SO(2) 3 days before birth (RR = 1.07; 95% CI, 0.99–1.15), adjusting for covariates, including temperature, dew point temperature, and day of the week. The results from this time-series analysis, which provides evidence of an increase in preterm birth risk with exposure to PM(10) and SO(2), are consistent with prior investigations of spatial contrasts

Vector Competence of Argentine Mosquitoes (Diptera: Culicidae) for West Nile virus (Flaviviridae: Flavivirus)

We examined the ability of Culex pipiens L. complex mosquitoes from Argentina to vector West Nile virus (WNV) to assess their role in the transmission of WNV in South America. Several egg rafts of Culex spp. were collected from different breeding sites in the suburbs of the city of La Plata, Argentina, and a subset of each progeny was scored with morphological and genetic species indicators. Surprisingly, we did not find Cx. pipiens form pipiens, but found evidence of genetic hybrids of Culex quinquefasciatus and Cx. pipiens f. molestus. We then used morphological traits to create two colonies predominantly composed of one of these two taxa, although some hybrids are likely to have been included in both. These colonies were used in vector competence studies using NY99 and WN02 genotype strains of WNV obtained in New York State. As controls, we also tested colonies of U.S. Cx. quinquefasciatus and Cx. pipiens f. molestus. Additional Culex larvae from three drainage ditches near the cities of La Plata and Berisso, Argentina, were identified by morphological and high-resolution molecular markers (microsatellites) as Cx. quinquefasciatus Say, Cx. pipiens form molestus, and hybrids. Results indicate that Argentinian Culex are competent but only moderately efficient vectors of WNV and are less susceptible to this virus than comparable U.S. mosquito strains. Studies of vertical transmission of NY99 virus by Cx. pipiens f. molestus hybrids from Argentina yielded a minimal filial infection rate of 1.19 from females feeding during their second and later bloodmeals.Centro de Estudios Parasitológicos y de Vectore

You’re an Engineer? You Must Be Really Smart! A Theoretical Discussion of the Need to Integrate “Smart” into Engineering Identity Research

Background: Those who participate in engineering are often assumed to be smart by others. At the same time, the cultural construction of what counts as “smart” is biased and therefore functions as a barrier to broadening participation in engineering. While considerable work has been done to understand engineering identity, how students understand themselves as smart is rarely made explicit in engineering identity research. Purpose: This paper is a theoretical discussion which highlights the need for engineering identity research to integrate students’ understanding of themselves as smart. By not incorporating students’ understanding of themselves as smart explicitly in work on engineering identity, we allow the bias in what gets recognized as smart to remain implicit and oppressive. Scope: In this paper, we argue that the idea of smart is very salient in engineering contexts and contributes to inequity. Then, we demonstrate how three different framings of identity allow for the explicit integration of how students are understanding themselves as smart. We also present selected examples from our empirical data to illustrate the concrete ways in which students’ understandings of themselves as smart manifest in an engineering context. Conclusions: We provided explicit opportunities for researchers to integrate students’ understandings of themselves as smart across three different framings of identity and how such understanding has shown up in our empirical research. In doing so, we conclude that making “smart” explicit in engineering identity provides a way to understand the exclusionary nature of engineering, and a new lens to apply when considering efforts to broaden participation in engineering