Lesson Planning and Video Analysis as Data Tools for Assessing PCK

This presentation addressed research on science and mathematics teacher learning in the context of an alternative certification program.National Science Foundatio

Optical and structural properties of ternary nanoaggregates in CsI-PbI2 co-evaporated thin films

Thin films were grown by vacuum co-evaporation of CsI and PbI2 compounds from two independent crucibles. X-ray diffraction spectroscopy revealed formation of CsPbI3 and Cs4PbI6 nanoaggregates in the thin film samples and gave an estimate of their volume percentage as well. It provided also the grain size estimates, which were compared with direct observation of a thin film surface by atomic force microscopy. The absorption, luminescence and decay kinetics characteristics of thin films grown were measured. The optical characteristics of the mentioned ternary nanoaggregates were determined and compared with those of CsPbX3 and Cs4PbX6 (X = Cl, Br) bulk structures

Combined theoretical and computational study of interstrand DNA guanine–guanine cross-linking bytrans-[Pt(pyridine)2] derived from the photoactivated prodrugtrans,trans,trans-[Pt(N3)2(OH)2(pyridine)2]

Molecular modeling and extensive experimental studies are used to study DNA distortions induced by binding platinum(II)-containing fragments derived from cisplatin and a new class of photoactive platinum anticancer drugs. The major photoproduct of the novel platinum(IV) prodrug trans,trans,trans-[Pt(N3)2(OH)2(py)2] (1) contains the trans-{Pt(py)2}2+ moiety. Using a tailored DNA sequence, experimental studies establish the possibility of interstrand binding of trans-{Pt(py)2}2+ (P) to guanine N7 positions on each DNA strand. Ligand field molecular mechanics (LFMM) parameters for Pt–guanine interactions are then derived and validated against a range of experimental structures from the Cambridge Structural Database, published quantum mechanics (QM)/molecular mechanics (MM) structures of model Pt–DNA systems and additional density-functional theory (DFT) studies. Ligand field molecular dynamics (LFMD) simulation protocols are developed and validated using experimentally characterized bifunctional DNA adducts involving both an intra- and an interstrand cross-link of cisplatin. We then turn to the interaction of P with the DNA duplex dodecamer, d(5′-C1C2T3C4T5C6G7T8C9T10C11C12-3′)·d(5′-G13G14A15G16A17C18G19A20G21A22G23G24-3′) which is known to form a monofunctional adduct with cis-{Pt(NH3)2(py)}. P coordinated to G7 and G19 is simulated giving a predicted bend toward the minor groove. This is widened at one end of the platinated site and deepened at the opposite end, while the P–DNA complex exhibits a global bend of 67° and an unwinding of 20°. Such cross-links offer possibilities for specific protein–DNA interactions and suggest possible mechanisms to explain the high potency of this photoactivated complex

Preservice Teachers\u27 Strategies for Teaching Mathematics with English Learners

Although English learners (ELs) are one of the fastest growing groups of students in the United States, many teacher preparation programs have yet to require preservice teachers (PSTs) to receive training in effective practices for teaching ELs. We examined four elementary PSTs’ instructional practices when implementing cognitively demanding mathematics tasks with ELs during a 4-week field experience. Through interviews, observations, and written reflections, we found that the PSTs tried to support the ELs, with varying degrees of success, by allowing for multiple modes of communication, including visual supports, pressing for explanations, and checking for understanding. The PSTs’ use of these strategies during the field experience was largely in response to the ELs’ use of language rather than mathematics. Furthermore, although the PSTs’ attention to linguistic supports was well intentioned, it often resulted in the PSTs taking on much of the mathematical thinking or failing to consider different student mathematical conceptions. We conclude that explicit instruction in and reflection on effective instructional strategies with ELs, set in authentic experiences, could help PSTs to more effectively develop the knowledge and skills necessary to meet the needs of ELs in the mathematics classroom

Introducing Dialogic Teaching to Science Student Teachers

It is commonly believed that science teachers rely on language that allows only minor flexibility when it comes to taking into account contrasting views and pupil thoughts. Too frequently science teachers either pose questions that target predefined answers or simply lecture through lessons, a major concern from a sociocultural perspective. This study reports the experiences of science student teachers when introduced to the Communicative Approach to science education drawing on dialogic teacher-talk in addition to authoritative teacher-talk. This approach was introduced to the students in an interventional teaching program running parallel to the student teachers’ field practice. The practical implications of this approach during initial teacher education are the central focus of this study. The data consisting of videos of lessons and interviews indicate that the student teacher awareness of teacher-talk and alternative communicative options did increase. Student teachers reported greater awareness of the different functions of teacher-talk as well as the challenges when trying to implement dialogic teaching.peerReviewe