Mathematics as a Gatekeeper to Engineering: Preliminary Findings from the Interview Data

Mathematics as a Gatekeeper to Engineering: Preliminary Findings from the Interview DataResearch suggests that students’ pre-college experience may support or hinder future success inengineering. The experiences that students have had with engineering may shape their perceptionof engineering curriculum at the college level. It may also cause cognitive and learningdissonance, when the ways that a student engaged with engineering activities at the pre-collegelevel do not align with the student’s experiences in the engineering classroom. At a largeMidwestern University with a unique first-year engineering program, first-year engineering andsenior mathematics, engineering, and design students were invited to participate in an openended design task. After completing the task, they were interviewed about how they solved thestudy design task as well as about their perceptions of their mathematical and design abilities.Finally, the students provided insight into their previous experiences with engineering.This paper will present findings and discussion based upon the students’ responses in the follow-up interview. Some emergent themes in the student’s responses are: 1) pre-college engineeringexperiences are structurally different than college engineering experiences, 2) students fail torecognize the diverse types of mathematical knowledge they are applying to solve the design taskand 3) pre-college engineering is more hands-on than college engineering coursework. Weanticipate that this work will give instructors insight in to the perceptions and experiences thatstudents have when they enter the engineering classroom as freshmen and how those ideas maychange over time as they work towards completing their degree. This work may also contributeto on-going discussions about how students understand the relationship between engineering,design and mathematical thinking as they are solving everyday engineering problems

Persistence of low pathogenic influenza A virus in water: a systematic review and quantitative meta-analysis

Avian influenza viruses are able to persist in the environment, in-between the transmission of the virus among its natural hosts. Quantifying the environmental factors that affect the persistence of avian influenza virus is important for influencing our ability to predict future outbreaks and target surveillance and control methods. We conducted a systematic review and quantitative meta-analysis of the environmental factors that affect the decay of low pathogenic avian influenza virus (LPAIV) in water. Abiotic factors affecting the persistence of LPAIV have been investigated for nearly 40 years, yet published data was produced by only 26 quantitative studies. These studies have been conducted by a small number of principal authors (n = 17) and have investigated a narrow range of environmental conditions, all of which were based in laboratories with limited reflection of natural conditions. The use of quantitative meta-analytic techniques provided the opportunity to assess persistence across a greater range of conditions than each individual study can achieve, through the estimation of mean effect-sizes and relationships among multiple variables. Temperature was the most influential variable, for both the strength and magnitude of the effect-size. Moderator variables explained a large proportion of the heterogeneity among effect-sizes. Salinity and pH were important factors, although future work is required to broaden the range of abiotic factors examined, as well as including further diurnal variation and greater environmental realism generally. We were unable to extract a quantitative effect-size estimate for approximately half (50.4%) of the reported experimental outcomes and we strongly recommend a minimum set of quantitative reporting to be included in all studies, which will allow robust assimilation and analysis of future findings. In addition we suggest possible means of increasing the applicability of future studies to the natural environment, and evaluating the biological content of natural waterbodies.Antonia E. Dalziel, Steven Delean, Sarah Heinrich, Phillip Casse

Distribution and Abundance of the Dugong in Gulf of Carpentaria Waters: a basis for cross-jurisdictional conservation planning and management

[Extract] This survey provides the first synopsis of the distribution and abundance of the dugong in the Gulf of Carpentaria. The results of previous surveys of parts of this region in both Queensland and the Northern Territory have been difficult to interpret because of the potentially confounding influences of unpredictable dugong movements between areas within the region

The influence of three endodontic sealers on bone healing: an experimental study

Background: The aim of this experimental study is to assess the bone healing phenomenon produced in the presence of 3 dental materials used for the root canal obturation. Materials and methods: The biocompatibility of 3 endodontic sealers (a self-curing epoxy resin — AH Plus, a dual cure urethane dimethacrylate resin — RealSeal and a new dual cure endodontic hydroxyapatite based filling material) was investigated after intra-osseous implantation of the materials in rats’ calvaria. Tissue reaction was studied at 2, 4, 6, 8, 10 and 12 weeks after implantation using calibrated image retrieval by Olympus. We took into consideration the presence of inflammatory cells (polymorphonuclear leukocytes, macrophages, plasma cells, lymphocytes and giant cells) and classified the aspects of the histological samples according to the following scale: 0 — no inflammation, 1 — mild, isolated inflammation, 2 — moderate, localised inflammatory reaction, 3 — severe, diffuse and intense inflammatory reaction. Results: The inflammatory reaction was present at the 6 intervals for all the tested materials, but a decrease of the inflammatory infiltrate, statistically significant, until extinction for all tested materials was observed at the end of the experimental period. The reaction of bone tissue recovery was most intense in the case of the control area. Lower intensity osteogenesis phenomenon was observed in case of all 3 tested sealers at the end of the experimental period. Conclusions: Biocompatibility and bone healing induction of the new hydroxyapatite based endodontic filling material is comparable to other commercial materials, AH Plus and RealSeal

A Tale of Two Design Contexts: Quantitative and Qualitative Explorations of Student-Instructor Interactions Amidst Ambiguity

Designers develop design skills and knowledge through experience and feedback – feedback from colleagues, clients, supervisors, users, stakeholders, the success or failure of a solution, and design educators. In this project, we focus on the feedback provided to mechanical engineering students completing their undergraduate studies and industrial design graduate students during design reviews. The design coaches (educators and industry clients) and design students must negotiate ambiguity in the process. The students must reduce ambiguity in the sense of providing clear details as they communicate their design work, reduce ambiguity in the coaches’ perceptions of the design work quality by providing evidence and rationales for their design approaches. However, they also maintain ambiguity in the sense of not converging on an idea too quickly in the design process, but instead considering many possibilities. We investigate the different forms of feedback provided by coaches, students’ responses to the feedback, and the ways the students and coaches navigate ambiguity. Finally, we characterize differences between the two environments in terms of the types of feedback given and students’ responses to the feedback

Lasting the distance: The survival of alien birds shipped to New Zealand in the 19th century

Invasive alien species are a major threat to biodiversity and human activities, providing a strong incentive to understand the processes by which alien invasion occurs. While it is important to understand the determinants of success at each of several invasion stages—transport, introduction, establishment, and spread—few studies have explored the first of these stages. Here, we quantify and analyze variation in the success of individual animals in surviving the transport stage, based on shipping records of European passerines destined for New Zealand. We mined the original documents of Acclimatisation Societies, established in New Zealand for the purpose of introducing supposedly beneficial alien species, in combination with recently digitized newspaper archives, to produce a unique dataset of 122 ships that carried passerines from Europe to New Zealand between 1850 and 1885. For 37 of these shipments, data on the survival of individual species were available. Using generalized linear mixed models, we explored how survival was related to characteristics of the shipments and the species. We show that species differed greatly in their survival, but none of the tested traits accounted for these differences. Yet, survival increased over time, which mirrors the switch from early haphazard shipments to larger organized shipments. Our results imply that it was the quality of care received by the birds that most affected success at this stage of the invasion process

Where did all the pangolins go? International CITES trade in pangolin species

Available online 24 October 2016The pangolin is greatly sought after for its various body parts, largely driven by demand from China. The mammal has been driven to the edge of extinction in Asia, with two Asian species listed as Critically Endangered in the International Union for Conservation of Nature Red List. With declining Asian pangolin populations, a shift in trade from Asian to African pangolin species has been suggested. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Trade Database provides a unique opportunity to investigate global trends in pangolin trade at the species level, across a broad temporal scale (1977–2014). We found that CITES trade in Asian pangolin species decreased through time, whilst trade in African species increased post 2000. The total number of incidents involving Asian species declined since 2000, yet they were still being traded in large volumes (more than 17,500 estimated whole Asian pangolins were traded from 2001 to 2014) despite a zero export quota for all wild sourced Asian species, traded for primarily commercial purposes. In 2014 all eight pangolin species were recorded in the CITES trade for the first time. An increasingly complex international network was identified through time, with the United States of America (US) being the dominant player in the global pangolin trade that was reported to CITES. The US was the most frequent trade country throughout the entire period and was the greatest importer of pangolins, and their products; measured both in volume as well as frequency. We hope that identifying these global trade network characteristics, and pangolin trade dynamics will help to inform pangolin conservation efforts, and guide enforcement and legislative changes in the future.Sarah Heinrich, Talia A. Wittmann, Thomas A.A. Prowse, Joshua V. Ross, Steven Delean, Chris R. Shepherd, Phillip Casse

The Environmental Estrogen Bisphenol A Inhibits Estradiol-Induced Hippocampal Synaptogenesis

Bisphenol A (BPA) is an estrogenic chemical that is widely used in the manufacture of plastics and epoxy resins. Because BPA leaches out of plastic food and drink containers, as well as the BPA-containing plastics used in dental prostheses and sealants, considerable potential exists for human exposure to this compound. In this article we show that treatment of ovariectomized rats with BPA dose-dependently inhibits the estrogen-induced formation of dendritic spine synapses on pyramidal neurons in the CA1 area of the hippocampus. Significant inhibitory effects of BPA were observed at a dose of only 40 μg/kg, below the current U.S. Environmental Protection Agency reference daily limit for human exposure. Because synaptic remodeling has been postulated to contribute to the rapid effects of estrogen on hippocampus-dependent memory, these data suggest that environmental BPA exposure may interfere with the development and expression of normal sex differences in cognitive function, via inhibition of estrogen-dependent hippocampal synapse formation. It may also exacerbate the impairment of hippocampal function observed during normal aging, as endogenous estrogen production declines

Spatial and temporal variation in the effects of climatic variables on Dugong calf production

Knowledge of the relationships between environmental forcing and demographic parameters is important for predicting responses from climatic changes and to manage populations effectively. We explore the relationships between the proportion of sea cows (Dugong dugon) classified as calves and four climatic drivers (rainfall anomaly, Southern Oscillation El Niño Index [SOI], NINO 3.4 sea surface temperature index, and number of tropical cyclones) at a range of spatially distinct locations in Queensland, Australia, a region with relatively high dugong density. Dugong and calf data were obtained from standardized aerial surveys conducted along the study region. A range of lagged versions of each of the focal climatic drivers (1 to 4 years) were included in a global model containing the proportion of calves in each population crossed with each of the lagged versions of the climatic drivers to explore relationships. The relative influence of each predictor was estimated via Gibbs variable selection. The relationships between the proportion of dependent calves and the climatic drivers varied spatially and temporally, with climatic drivers influencing calf counts at sub-regional scales. Thus we recommend that the assessment of and management response to indirect climatic threats on dugongs should also occur at sub-regional scales. © 2016 Fuentes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Preliminary revision of the morphology of Phyllozoon hanseni from the Ediacaran of South Australia

Abstract and Keywords in Spanish and EnglishEn este trabajo se analiza la morfología de Phyllozoon hanseni Jenkins y Gehling, un organismo fósil con forma de fronde y de simetría deslizada del Ediacárico de la Sierra de Flinders, Australia del Sur. El estudio se centra en la medición de los parámetros básicos de estos fósiles con la intención de identificar tendencias que sean diagnósticas para P. hanseni, ayudar a definir su morfología funcional, y reconciliar esta información con el contexto paleobiológico. Los principales hallazgos han sido que el tamaño de los ejemplares presenta una distribución no-normal y de sesgo negativo, y que los extremos de P. hanseni son muy distintos. Uno lo denominamos ‘cuchara’, y es redondeado, con unidades anchas dispuestas en ángulo agudo respecto al eje sagital. Dicho ángulo es mayor hacia el ápice y le confiere a éste un aspecto de pimpollo de rosa. La primera unidad consistentemente está en el lado izquierdo del epirelieve positivo. El otro extremo, el ‘cuchillo’, tiene un característico descenso lineal de anchura y longitud de sus unidades, que se mantienen perpendicular al eje del organismo. El área central, entre estas dos secciones, presenta bordes subparalelos, y lo denominamos ‘tronco’. Se ha detectado una fuerte correlación positiva entre la Longitud Mínima del Ejemplar y el Número Mínimo de Unidades, así como una moderada correlación positiva entre anchura y longitud de las unidades en la región central. Adicionalmente, los resultados sugieren un patrón de crecimiento asimétrico entre el incremento de tamaño y el número total de unidades desde el ápice del ‘cuchillo’. La morfología observada en P. hanseni se interpreta como un indicio de hábito bentónico postrado. = We have investigated the morphology of Phyllozoon hanseni Jenkins and Gehling, a frond-like fossil organism with glide reflection symmetry from the Ediacaran of the Flinders Ranges, South Australia. The focus of this study was to measure some basic physical parameters of these fossils to identify some distinguishing trends, to help build a picture of the functional morphology of P. hanseni, and then to reconcile this information in a palaeobiological context. The main findings are that specimen length displayed a non-normal, negatively skewed distribution, and that P. hanseni possesses two distinct ends. One dubbed here the ‘spoon’, is rounded in profile, with steep-angled positioning of thicker units and a rosebud-like appearance at the terminus, found to always begin on the left bank of the positive hyporelief. The other end, the ‘knife’, displays instead a gradual decrease in both unit width and length with positioning of units perpendicular to the body axis. The area between these two sections, with sub-parallel edges, is referred to as the ‘trunk’. Specimen length was found to be positively associated with both unit number and specimen width. Additionally, the findings suggest a longitudinally asymmetrical growth pattern of increasing size and number of units, with serial addition of units at the knife terminus. The observed morphology of P. hanseni suggests a lifestyle as a benthic, prostrate organism.Ashten M. Turner, Steven Delean, Diego C. García-Bellid