Identification of a nonlinear dynamic biological model using the dominant parameter selection method

The identification of nonlinear models sometimes encounters problems because of the limited amount of available measurements in combination with a large number of uncertain model parameters to be identified. E.g., the determination of the chemical composition of a lettuce crop is a rather expensive procedure; thus the number of experimental measurements is limited. As a result, the number of parameters of the dynamic model that can be successively identified is also limited, and the subset of the parameters to be identified must be chosen in a reasonable way.Parameter estimation for an extended nonlinear three-state model for lettuce growth in greenhouses is presented in this paper. The varying structural nitrogen concentration and water contents are the new elements included in the model. The dominant parameter selection (DPS) method was used to select a suitable set of identifiable parameters. The resulting calibrated model predicts quite well the experimental data which also include observations with severe nitrogen stress.     

Consolidating properties of Regalrez 1126 and Paraloid B72 applied to wood

This study is aimed at an assessment of the properties of two polymeric products applied to Norway spruce (Picea abies) and White poplar (Populus alba) wood species. It contributes to ongoing research experiments on the consolidating properties of two synthetic resins and their potential synergic action on wood, resulting from their different interaction with the substrate: Paraloid B72 and Regalrez 1126. Experiments were carried out on a series of samples of the two wood varieties. The consolidants were applied alone and one after the other, with one coat of Regalrez and then one of Paraloid. Porosity and variations in pore size distribution were ascertained by mercury intrusion porosimetry (MIP). Colorimetric and IR spectroscopic measurements were also taken before and after aging by solar radiation and freeze/thaw cycles, to verify the possible slowing of photodegradation of the treated wood and the consolidating resistance. Results confirm that both products penetrate the wood with a different behaviour. After double treatment with Regalrez + Paraloid, a significant advantage was observed in terms of mechanical resistance and pore size distribution, although no advantages as regards resistance to photo-oxidizing processes or colour changes were observed.     

Ammonium oxalate treatment: Evaluation by μ-Raman mapping of the penetration depth in different plasters

This study is focused on the evaluation by μRaman mapping of the penetration depth achieved by ammonium oxalate treatment in different plaster specimens, a hot issue in the conservation field. The role of the carbonatic aggregate particles and the influence of the different variables of the treatment on the penetration depth and on the distribution of the newly-formed phase (whewellite) have been ascertained. Based on the results of μRaman mapping, analyses with Field Emission Scanning Electron Microscopy have been carried out in order to observe the whewellite crystals and the carbonatic aggregate particles involved in the reaction with ammonium oxalate.     

Learning from human cadaveric prosections: Examining anxiety in speech therapy students

Human anatomy education often utilizes the essential practices of cadaver dissection and examination of prosected specimens. However, these exposures to human cadavers and confronting death can be stressful and anxiety‐inducing for students. This study aims to understand the attitudes, reactions, fears, and states of anxiety that speech therapy students experience in the dissection room. To that end, a before‐and‐after cross‐sectional analysis was conducted with speech therapy students undertaking a dissection course for the first time. An anonymous questionnaire was administered before and after the exercise to understand students' feelings and emotions. State‐Trait Anxiety Inventory questionnaires (STAI‐S and STAI‐T) were used to evaluate anxiety levels. The results of the study revealed that baseline anxiety levels measured using the STAI‐T remained stable and unchanged during the dissection room experience (P > 0.05). Levels of emotional anxiety measured using the STAI‐S decreased, from 15.3 to 11.1 points (P < 0.05). In the initial phase of the study, before any contact with the dissection room environment, 17% of students experienced anxiety, and this rate remained unchanged by end of the session (P > 0.05). A total of 63.4% of students described having thoughts about life and death. After the session, 100% of students recommended the dissection exercise, giving it a mean score of 9.1/10 points. Anatomy is an important subject for students in the health sciences, and dissection and prosection exercises frequently involve a series of uncomfortable and stressful experiences. Experiences in the dissection room may challenge some students' emotional equilibria. However, students consider the exercise to be very useful in their education and recommend it. Anat Sci Educ 10: 487–494. © 2017 American Association of Anatomists.     

The Elusive Relationship Between Teacher Characteristics and Student Academic Growth: A Longitudinal Multilevel Model for Change

Teacher characteristics and student achievement growth are currently a significant topic of investigation in the educational accountability arena. Given the environment of high-stakes accountability associated with the No Child Left Behind (NCLB) legislation and state accountability systems, staffing all classrooms with highly qualified teachers is a critical national concern. A new era of research is needed to understand the complexity of teacher quality when defined by student learning growth. The present study evaluated the effects of teacher characteristics (i.e., experience, education, and race) in high school reading achievement gains using a multi-level growth model in an urban school district in Kentucky. Findings showed significant effects of time, but non-significant effects of teacher characteristics in high school reading achievement growth. Implications for educational policy and future research are discussed.     

Evaluating Teacher-Leaders for Careers as Administrators: Effects of Job Attributes, Teacher Leader Role, and Teaching Assignment Area

Recruitment of public school administrators is an important issue due to the shortage of qualified job applicants nationwide. The shortage of applicants requires school districts to evaluate their internal pools of potential applicants for administrative vacancies. This evaluation research addressed the recruitment of teacher-leaders to serve as assistant principals (APs) using a recruitment simulation technique. The participants were secondary school teacher-leaders who were counselors, school council members, department chairs, or resource teachers. The evaluation technique used involved an innovative experimental design approach. Teacher-leaders, whose current or past primary teaching assignment was in the core content areas (e.g., English/language arts, mathematics, science, social studies), rated the job of AP highest. Resource teachers rated the job significantly higher when the AP job emphasized instruction than when the job emphasized discipline. Implications for recruitment practice and future research are discussed.     

Understanding teachers' attitudes to change in a Logomathematics environment

We describe the views and attitudes of a group of Portuguese primary teachers as they unfolded during a course aimed at introducing a Logo-mathematical culture. We identify what was at stake for them in interacting with such a culture by focusing on sketches of two participants. The study had threefold aims: to describe and analyse attitudes towards mathematics and mathematics teaching; to examine the interactions between participants' attitudes and their activities on the course; and to investigate what kinds of influences the course had on their attitudes.     

How to Analyze Interpersonal and Individual Effects in Peer-Tutored Reading Intervention

Reading strategy interventions relying upon peer tutoring are a common way to foster poor readers' comprehension skills. Those interventions are based on the assumption that tutees benefit from the (higher) reading skills of their tutors. However, this interpersonal effect has not yet been tested explicitly because the effectiveness of peer tutoring is commonly analyzed separately for tutees and tutors or with aggregated data. The present study illustrates how interpersonal and individual effects of a peer-tutored reading strategy intervention can be estimated using dyads as units of analysis in structural equation modeling. To demonstrate the application of the model, data from an experimental intervention study comparing the effects of a peer-tutored reading strategy training and a control condition in Grade 4 (N = 68 dyads) were analyzed.     

Deprivation level and choice in pigeons: a test of within-trial contrast

Within-trial contrast has been proposed as a mechanism underlying preferences for stimuli that follow relatively more aversive events over stimuli that follow less aversive events. In this study, we manipulated deprivation level to test within-trial contrast predictions. In Experiment 1, pigeons encountered two discriminative stimuli, one presented when they were deprived and the other when they were prefed. When later given a choice between the two stimuli, pigeons strongly preferred the stimulus encountered when deprived, independently of their deprivation level at test. In Experiment 2, pigeons learned two simultaneous discriminations, one when deprived and the other when prefed. Here, subsequent tests between the two S⁺ or the two S⁻ stimuli revealed no consistent preferences. These contrasting findings suggest that differential aversiveness is necessary but not sufficient to induce preferences via within-trial contrast.