Developing Elementary Teachers’ Understandings of Hedges and Personal Pronouns in Inquiry-Based Science Classroom Discourse

This study examined the effectiveness of introducing elementary teachers to the scholarly literature on personal pronouns and hedges in classroom discourse, a professional development strategy adopted during a summer institute to enhance teachers’ social understanding (i.e., their understanding of the social functions of language in science discussions). Teachers became aware of how hedges can be employed to remain neutral toward students’ oral contributions to classroom discussions, invite students to share their opinions and articulate their own ideas, and motivate students to inquire. Teachers recognized that the combined use of I and you can render their feedback authoritative, you can shift the focus from the investigation to students’ competence, and we can lead to authority loss. It is argued that explicitness, reflectivity, and contextualization are essential features of professional development programs aimed at improving teachers’ understandings of the social dimension of inquiry-based science classrooms and preparing teachers to engage in inquiry-based teacher–student interactions.     

Botany and environmental education in elementary school in Brazil: articulating knowledge,values, and procedures

Abstract

The increasing urbanization and alienation from nature reduce children’s opportunities to interact with plants and challenge teachers to devise educational practices that contribute to learning botany. This study presents the results of activities developed in a Brazilian school through explorations, drawings, dried and pressed specimens, and semi-structured interviews. The data were evaluated using mixed methods analysis. Leaves were the structure that was most frequently drawn by 1st- and 2nd-year students, followed by stems. Among students in their 3rd, 4th, and 5th years, more emphasis was on flowers and their detailed morphological structures. The 1st- and 2nd-year students included non-living elements and the surrounding environment in their drawings, whereas the older students focused on the plant itself. These particularities point to methods of teaching botany in context and link students’ specific knowledge to values and practices that contribute to an environmental education that aims to minimize the utilitarian view of nature and move towards a view of human beings as integrated and interdependent with other living and non-living elements.     

From professional development to classroom instruction: addressing issues related to science inquiry discourse

In this rejoinder, I first provide a more detailed account of the discourse-focused professional development activities facilitated as part of the SMIT’N program, specifically addressing issues raised by van Zee with regard to the institute’s overall format, goals and development strategies. Next, I resort to Peter Medawar’s metaphorical view of inquiry as scientific storytelling to reflect about Bencze’s expressed opposition to “politely guided quasi-inductive science inquiry instruction” and highlight the need for science educators to give more careful consideration to oral classroom discourse. I then conclude by describing how guided science inquiry teaching can be conceived in terms of the theoretical notion of negative politeness.     

Output-feedback binary adaptive control of MIMO systems using monitoring function

The problem of adaptive control design for multivariable linear time-invariant plants with unknown control direction is considered. A solution is proposed based on the SDU factorization of the high frequency gain matrix (HFG) and the monitoring function approach. The adaptation scheme is the binary model reference adaptive control (BMRAC) which utilizes parameter projection and sufficiently high adaptation gains. The signs of the leading principal minors of the HFG define the control directions, and the lack of knowledge of which is a major challenge in the multivariable framework. The role of the monitoring function is to monitor the output error transient and then provide the necessary changes of the adaptation gain signs to guarantee a stable adaptive control. In addition to proving the signal boundedness of the resulting closed-loop system, the output tracking error is shown to be asymptotically as well as exponentially practically stable, i.e., exponentially stable with respect to a small residual compact set of size inversely proportional to the BMRAC adaptation gain. The latter implies good transient properties of the output tracking error in contrast to conventional adaptive laws which only guarantee asymptotic stability but can lead to extremely slow error convergence. The extension of the proposed approach to matched disturbances is also briefly discussed following the classical paradigm of disturbance estimators. Numerical results with a visual servoing application illustrate the efficiency of the proposed method.     

Leg preference and interlateral asymmetry of balance stability in soccer players

To examine the effect of long lasting practice on pedal behavior in sport, we compared experienced adult soccer players and nonsoccer players on leg preference in motor tasks requiring general mobilization, soccer related mobilization, and body balance stabilization. We also evaluated performance asymmetry between the right and left legs in static and dynamic unipedal body balance, based on center of pressure displacement, and correlated that with leg preference in balance stabilization tasks. Results revealed (a) a distinct leg preference between mobilization and stabilization tasks, which were significantly different between players and nonplayers, (b) similar balance stability between the right and left legs, (c) greater stability of experienced players compared with nonplayers in static and dynamic balance, and (d) absence of a significant leg preference correlation with interlateral balance asymmetry. These results suggest an effect of extensive soccer skill practice on establishing leg preference for specific mobilization tasks and overall balance control.     

Strong delay-independent stability of linear delay systems

This paper presents a new necessary and sufficient condition for testing the strong delay-independent stability of linear systems subject to a single delay. The proposed method follows from the use of matrix polynomials constraints and the Kalman–Yakubovich–Popov lemma. The resulting condition can be checked exactly by solving a feasibility problem in terms of a linear matrix inequality (LMI). Simple numerical examples are given to show the effectiveness of the proposed method.     

Teacher Accommodation of Academic Language During Head Start Pre-Kindergarten Read-Alouds

Abstract

Little analytical scrutiny has been devoted to teacher accommodation of academic language at the early childhood level, despite being a critical school-level factor to consider when addressing at-risk learners’ academic needs. The present study investigates how fifteen Head Start teachers support three components of academic language during whole-class read-alouds of narrative storybooks: academic vocabulary, conceptual knowledge, and complex syntax. Pairing a corpus-based analysis of linguistic features and content analyses of teachers’ extratextual utterances, we describe teachers’ strategies for accommodating at-risk children’s early experiences with linguistically and syntactically complex texts. Our findings indicate that teachers simplified the language of the texts to accommodate student need, while also providing examples of academic talk through defining terms and providing conceptually-rich talk. Although teachers provided rich support for academic vocabulary, less accommodation was made for complex syntax. Practical and theoretical implications are addressed.     

Extensional flow of hyaluronic acid solutions in an optimized microfluidic cross-slot device

We utilize a recently developed microfluidic device, the Optimized Shape Cross-slot Extensional Rheometer (OSCER), to study the elongational flow behavior and rheological properties of hyaluronic acid (HA) solutions representative of the synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation point device that imposes a planar extensional flow with a homogenous extension rate over a significant length of the inlet and outlet channel axes. Due to the compressive nature of the flow generated along the inlet channels, and the planar elongational flow along the outlet channels, the flow field in the OSCER device can also be considered as representative of the flow field that arises between compressing articular cartilage layers of the knee joints during running or jumping movements. Full-field birefringence microscopy measurements demonstrate a high degree of localized macromolecular orientation along streamlines passing close to the stagnation point of the OSCER device, while micro-particle image velocimetry is used to quantify the flow kinematics. The stress-optical rule is used to assess the local extensional viscosity in the elongating fluid elements as a function of the measured deformation rate. The large limiting values of the dimensionless Trouton ratio, Tr ∼ O(50), demonstrate that these fluids are highly extensional-thickening, providing a clear mechanism for the load-dampening properties of SF. The results also indicate the potential for utilizing the OSCER in screening of physiological SF samples, which will lead to improved understanding of, and therapies for, disease progression in arthritis sufferers.