Project-Based Learning and its Impact on High School Students\u27 Attitudes Towards Mathematics: A Quantitative Study

This quantitative, quasi experimental, nonequivalent control group study analyzed the relationship between students engaging in project-based learning and its impact on their attitudes towards mathematics. Sixty-six high school students taking a non-entry level mathematics class participated in the study. This study compared students taking the same high school mathematics course with one group taught in the traditional way of lecture notes and tests and the second group being taught using projects. These students’ responses from the Attitudes Towards Mathematics Inventory were compared using one-way analysis of covariance to determine a difference in student attitudes. The study determined that there was no significant statistical difference in student attitudes toward mathematics between the project-based group and the traditional instruction group when controlling for pretest scores. Future research recommendations include a longer timeframe, focusing on special education students, and making accommodations for English Language Learners to help ameliorate language barriers

Development of a chordate anterior–posterior axis without classical retinoic acid signaling

AbstractDevelopmental signaling by retinoic acid (RA) is thought to be an innovation essential for the origin of the chordate body plan. The larvacean urochordate Oikopleura dioica maintains a chordate body plan throughout life, and yet its genome appears to lack genes for RA synthesis, degradation, and reception. This suggests the hypothesis that the RA-machinery was lost during larvacean evolution, and predicts that Oikopleura development has become independent of RA-signaling. This prediction raises the problem that the anterior–posterior organization of a chordate body plan can be developed without the classical morphogenetic role of RA. To address this problem, we performed pharmacological treatments and analyses of developmental molecular markers to investigate whether RA acts in anterior–posterior axial patterning in Oikopleura embryos. Results revealed that RA does not cause homeotic posteriorization in Oikopleura as it does in vertebrates and cephalochordates, and showed that a chordate can develop the phylotypic body plan in the absence of the classical morphogenetic role of RA. A comparison of Oikopleura and ascidian evidence suggests that the lack of RA-induced homeotic posteriorization is a shared derived feature of urochordates. We discuss possible relationships of altered roles of RA in urochordate development to genomic events, such as rupture of the Hox-cluster, in the context of a new understanding of chordate phylogeny

Expression signatures of cisplatin- and trametinib-treated early-stage medaka melanomas

Small aquarium fish models provide useful systems not only for a better understanding of the molecular basis of many human diseases, but also for first-line screening to identify new drug candidates. For testing new chemical substances, current strategies mostly rely on easy to perform and efficient embryonic screens. Cancer, however, is a disease that develops mainly during juvenile and adult stage. Long-term treatment and the challenge to monitor changes in tumor phenotype make testing of large chemical libraries in juvenile and adult animals cost prohibitive. We hypothesized that changes in the gene expression profile should occur early during anti-tumor treatment, and the disease-associated transcriptional change should provide a reliable readout that can be utilized to evaluate drug-induced effects. For the current study, we used a previously established medaka melanoma model. As proof of principle, we showed that exposure of melanoma developing fish to the drugs cisplatin or trametinib, known cancer therapies, for a period of seven days is sufficient to detect treatment-induced changes in gene expression. By examining whole body transcriptome responses we provide a novel route toward gene panels that recapitulate anti-tumor outcomes thus allowing a screening of thousands of drugs using a whole-body vertebrate model. Our results suggest that using disease-associated transcriptional change to screen therapeutic molecules in small fish model is viable and may be applied to pre-clinical research and development stages in new drug discovery

Female Sex Development and Reproductive Duct Formation Depend on Wnt4a in Zebrafish.

In laboratory strains of zebrafish, sex determination occurs in the absence of a typical sex chromosome and it is not known what regulates the proportion of animals that develop as males or females. Many sex determination and gonad differentiation genes that act downstream of a sex chromosome are well conserved among vertebrates, but studies that test their contribution to this process have mostly been limited to mammalian models. In mammals, WNT4 is a signaling ligand that is essential for ovary and Müllerian duct development, where it antagonizes the male-promoting FGF9 signal. Wnt4 is well conserved across all vertebrates, but it is not known if Wnt4 plays a role in sex determination and/or the differentiation of sex organs in nonmammalian vertebrates. This question is especially interesting in teleosts, such as zebrafish, because they lack an Fgf9 ortholog. Here we show that wnt4a is the ortholog of mammalian Wnt4, and that wnt4b was present in the last common ancestor of humans and zebrafish, but was lost in mammals. We show that wnt4a loss-of-function mutants develop predominantly as males and conclude that wnt4a activity promotes female sex determination and/or differentiation in zebrafish. Additionally, both male and female wnt4a mutants are sterile due to defects in reproductive duct development. Together these results strongly argue that Wnt4a is a conserved regulator of female sex determination and reproductive duct development in mammalian and nonmammalian vertebrates

A Vision for Change in Bioscience Education: Building on Knowledge from the Past

High quality undergraduate education is central to the success of all life scientists. Several major bioscience educational issues are the targets of much debate, research, funding, publications, and reports (e.g. Vision and Change). Surprisingly, these issues are considered by modern bioscience instructors as unresolved despite historical reports that claim the contrary. Here we illustrate with evidence how, more than 50 years ago, Sam Postlethwait successfully instituted strategies to address several issues in plant biology education with his audio-­‐tutorials. These strategies succeeded in individualizing instruction of students with diverse educational backgrounds in large classes, incorporating authentic and active learning, integrating lab and lecture to teach about research, developing science competencies, and advancing curriculum and faculty change informed by empirical data. We contend that modern educators could greatly benefit by building on the historical advancements of the past, to ensure they do not waste their efforts re-­‐ inventing the wheel

Cupule Formation on Seedlings of Galinsoga Ciliata (RAF.) Blake and Helianthus Annuus L. Following Exposure to 2, 4-Dichlorophenoxyacetic Acid

Early experiments involving the use of various growth-promoting substances were concerned generally with formative effects and morphological changes induced by these substances. Later experiments were of a more practical nature in which the hormones were tested to determine their numerous commercial applications. The results of morphological investigations disclose the most common reactions to be: (1) cell division, (2) cell enlargement, (3) differentiation of the newly formed tissues, especially into vascular structures, (4) changes in the thickness of cell membranes, and (5) organ building manifested in the development of root primordia, or rarely as bud primordia (Bausor et. al., 1940). Only a few studies have been concerned with the response of leaves to 2, 4-D (Burton, 1947, Felber, 1948). The major emphasis of other morphological reports has been placed on the response of stems and other plant organs to this hormone

Suture Materials, 1980s: Properties, Uses, and Abuses

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66057/1/j.1365-4362.1982.tb03154.x.pd