46 research outputs found
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A case study of mobile internet technology in bilingual elementary classrooms
textResearch about the use of mobile Internet technology in education is increasing, but gaps remain in the literature. This study used a case study approach to understand how teachers in a bilingual English Language Learner (ELL) classroom used iPod touch devices in a Texas public elementary school. Unlike many other studies investigating the use of mobile Internet technology in education by motivated educators and researchers, this research focuses on an initiative where apprehensive teachers were mandated to integrate mobile Internet technology. It also has a relatively rare focus on the implementation process rather than learning outcomes. Research questions were designed to explore how teachers implemented the iPod touch devices, whether the implementation encouraged informal learning, and what implementation challenges arose. Data sources consisted of qualitative interviews with students, teachers, and a school administrator as well as classroom observations and an analysis of student artifacts. Data showed that many activities resulting from the implementation of the iPod touch initiative included elements of constructivist learning and encouraged student interaction. Another finding was that giving students full-time possession of the devices
did lead to students using the device outside of school, but that most of their activities involved practicing what they had learned in the classroom and not true informal learning. Overcoming teachers’ hesitancy and lack of familiarity with technology were found to be major obstacles early in the program, but findings suggested that training, support, and student enthusiasm overcame teachers’ initial reluctance. Implications of this research are that efforts to integrate mobile Internet technology with elementary-level ELLs need an active focus on informal learning to leverage the potential the devices offer. Also, successful implementation requires more than just the availability of the technology; it also requires training and support for teachers to increase their familiarity with the technology and to provide them with ideas that allow them to use the technology most effectively.Curriculum and Instructio
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Molecular Genetics of Beta-Lactam Sensitivity and Resistance in Mycobacterium Tuberculosis
Mycobacterium tuberculosis threatens global health. Its thick, impermeable cell wall renders it tolerant to high doses of many antibiotics. While we understand the biochemical functions of many cell wall-modifying enzymes, we often do not understand their physiological functions: their spatiotemporal roles in the cell cycle, their substrate preferences, or their individual effects on the macromolecular architecture of the cell wall complex. Mycobacterium tuberculosis possesses five peptidoglycan transpeptidases, five lytic transglycosylases, and numerous other peptidoglycan-modifying enzymes that lack precisely-understood roles. The lytic transglycosylases of Mycobacterium tuberculosis are collectively dispensable for in vitro growth. We sought to learn what other classes of peptidoglycan-degrading enzyme might substitute for the lytic transglycosylases or become essential in their absence. A high-throughput chemical screen was performed on a strain lacking all five lytic transglycosylases to identify compounds that specifically killed this strain and not wild-type Mycobacterium tuberculosis. Among the compounds identified were several members of the cephalosporin class of -lactam antibiotics. It was shown that the cephalosporins had greater access to the periplasmic -lactamase of Mycobacterium tuberculosis in the lytic transglycosylase-deficient strain and that this strain had enhanced sensitivity to several antibiotics with unrelated mechanisms of action. Together, greater periplasmic access and broadly heightened susceptibility in the deficient strain suggested a role for the lytic transglycosylases in maintaining the mycolic acid permeability barrier. To identify the specific penicillin-binding protein target of the cephalosporins, we isolated spontaneously-occurring resistant mutants. These strains contained polymorphisms in ponA2, a bifunctional penicillin-binding protein. The polymorphisms conferred sensitivity to heat stress, a phenotype associated with ponA2 loss of function. To clarify the relation between loss of function and cephalosporin resistance, a ponA2 deletion strain was created, which exhibited both cephalosporin resistance and sensitivity to carbapenems, another class of -lactam. Restoration of the wild-type ponA2 allele suppressed both cephalosporin resistance and carbapenem sensitivity. Inactivation of other transpeptidases did not confer resistance to any -lactams. The association of penicillin-binding protein inactivation with -lactam resistance is unusual. One model to explain it is that upon deletion of ponA2, Mycobacterium tuberculosis compensates for its loss by upregulating a cephalosporin-resistant, meropenem-sensitive transpeptidase
Examining How Middle School Science Teachers Implement a Multimedia-enriched Problem-based Learning Environment
This study examined how a group of ten middle school teachers implemented a technology enriched problem-based learning (PBL) environment. The goal was to understand their motivation, document their implementation techniques, and identify factors that teachers considered important in using technology-based PBL tools in their teaching. The analysis identified four factors that provided the impetus for teachers to consider the adoption of technology-based PBL instruction. These factors are (1) the PBL program addresses the teachers’ curricular needs and implementing it has campus administrative and technical support, (2) the method is aligned with teachers’ pedagogical beliefs, (3) the PBL program offers a new way of teaching and promotes the development of higher-order thinking skills, and (4) the PBL program challenges students in a captivating manner and supports the learning needs of all students. Teachers’ implementation techniques with over 1,000 sixth graders were documented in detail with regard to: 1) the teacher’s roles, 2) the student’s role, and 3) the classroom interactions during the implementation of the PBL program. In addition, a detailed description of contrasting narratives of two pairs of teachers is provided, illustrating the range of implementation techniques that can occur using the same PBL program to allow for individualized instruction to meet different students’ needs. The goal of providing detailed implementation practices is to address the lack of “how to” in PBL implementation in K-12 classrooms as indicated in the literature and offer insights and ideas to those interested in adopting and implementing PBL. Findings are discussed within the theoretical framework and implications are provided
Secretome profiling of Propionibacterium freudenreichii reveals highly variable responses even among the closely related strains
This study compared the secretomes (proteins exported out of the cell) of Propionibacterium freudenreichii of different origin to identify plausible adaptation factors. Phylosecretomics indicated strain-specific variation in secretion of adhesins/invasins (SlpA, InlA), cell-wall hydrolysing (NlpC60 peptidase, transglycosylase), protective (RpfB) and moonlighting (DnaK, GroEL, GaPDH, IDH, ENO, ClpB) enzymes and/or proteins. Detailed secretome comparison suggested that one of the cereal strains (JS14) released a tip fimbrillin (FimB) in to the extracellular milieu, which was in line with the electron microscopy and genomic analyses, indicating the lack of surface-associated fimbrial-like structures, predicting a mutated type-2 fimbrial gene cluster (fimB-fimA-srtC2) and production of anchorless FimB. Instead, the cereal strain produced high amounts of SlpB that tentatively mediated adherent growth on hydrophilic surface and adherence to hydrophobic material. One of the dairy strains (JS22), producing non-covalently bound surface-proteins (LspA, ClpB, AraI) and releasing SlpA and InlA into the culture medium, was found to form clumps under physiological conditions. The JS22 strain lacked SlpB and displayed a non-clumping and biofilm-forming phenotype only under conditions of increased ionic strength (300mM NaCl). However, this strain cultured under the same conditions was not adherent to hydrophobic support, which supports the contributory role of SlpB in mediating hydrophobic interactions. Thus, this study reports significant secretome variation in P.freudenreichii and suggests that strain-specific differences in protein export, modification and protein-protein interactions have been the driving forces behind the adaptation of this bacterial species.Peer reviewe
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MreB filaments align along greatest principal membrane curvature to orient cell wall synthesis
MreB is essential for rod shape in many bacteria. Membrane-associated MreB filaments move around the rod circumference, helping to insert cell wall in the radial direction to reinforce rod shape. To understand how oriented MreB motion arises, we altered the shape of Bacillus subtilis. MreB motion is isotropic in round cells, and orientation is restored when rod shape is externally imposed. Stationary filaments orient within protoplasts, and purified MreB tubulates liposomes in vitro, orienting within tubes. Together, this demonstrates MreB orients along the greatest principal membrane curvature, a conclusion supported with biophysical modeling. We observed that spherical cells regenerate into rods in a local, self-reinforcing manner: rapidly propagating rods emerge from small bulges, exhibiting oriented MreB motion. We propose that the coupling of MreB filament alignment to shape-reinforcing peptidoglycan synthesis creates a locally-acting, self-organizing mechanism allowing the rapid establishment and stable maintenance of emergent rod shape
Identification and distribution of Centaurium muhlenbergii (Griseb.) Piper and C. pulchellum (Sw.) Druce (Gentianaceae) in Louisiana, Mississippi, and Texas
Volume: 80Start Page: 23End Page: 2
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Replacing Blackboard: Finding a New Learning Management System for WPI
Poster Presentation, Judge\u27s Winner (2015)https://digitalcommons.wpi.edu/gps-posters/1425/thumbnail.jp
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Chip Recycling: Recycling of Chips from BZZ Conditioning Processes
This project, done in conjunction with Saint-Gobain Abrasives, responds to the rising cost of nickel and chromium, the major components of stainless steel by conducting a comprehensive cost analysis of the stainless steel production and recycling processes. Background research was performed with company surveys for important information about specific machines which recycle stainless steel chips. With these data, conclusions were prepared about the cost-effectiveness of recycling as opposed to selling or dumping the stainless steel chips. A cost structure analysis and new recycling methods for specific applications were proposed