Interrogation of Voids in SOlids Utilizing Ramp Function Ultrasonic Pulses

From some low frequency scattering investigations in radar, it is suggested that interrogating the target with ramp function has distinct advantages. This ramp function is a ramp in amplitude, not frequency. The returning echo is predicted to exhibit directly in the time domain, information of the cross-sectional area of a target as the ramp passes the target. From this information, one can infer size, volume, and orientation of the target. The theory for this interpretation is based on the physical optics approximation. This approximation is commonly used in acoustic and elastic wave scattering when the boundary conditions are approximate. The concepts can be verified by exact scattering theories for back-scatter from hard spheres (acoustic) and spherical voids (elastic). Our calculation for these two cases do show that their returning could show cross-sectional information. A proposed system to launch and receive ramp pulses will be discussed. The generation mechanism uses the demodulation properties of absorbtive, nonlinear media on a large amplitude pulse train. The detectior mechanism utilizes fiber optics

Improved omit set displacement recoveries in dynamic analysis

Two related methods for improving the dependent (OMIT set) displacements after performing a Guyan reduction are presented. The theoretical bases for the methods are derived. The NASTRAN DMAP ALTERs used to implement the methods in a NASTRAN execution are described. Data are presented that verify the methods and the NASTRAN DMAP ALTERs

Conservation in the dark? the information used to support management decisions

The management requirements for protected areas are frequently complex and urgent; as a result, managers often need to act quickly and make decisions with limited supporting evidence at their disposal. Despite demands for high-quality information, it is unclear how much of this evidence conservation practitioners use to assist with their decision making. We investigated the information used to manage protected areas, based on the evidence reported by practitioners when evaluating their management performance. We examined the management of over 1000 protected areas run by two Australian conservation agencies - Parks Victoria and the New South Wales Department of Environment and Climate Change - an unprecedented scope for this type of study. We found that very few conservation practitioners use evidence-based knowledge to support their management. The evidence used varies with the management issue, reserve type, and reserve size. Around 60% of conservation management decisions rely on experience-based information, and many practitioners report having insufficient evidence to assess their management decisions. While experience plays an important role in conservation management, the apparent lack of evidence-based information to support decision making in the reserves has the potential to compromise outcomes and jeopardize the investment made in protected areas for conservation

Fostering Agentic Engagement: Working toward Empowerment and Equity through Pedagogical Partnership

An established body of research details the faculty role in promoting student engagement. Newer scholarship on agentic engagement foregrounds student-initiated engagement in classroom learning. Our SoTL project explored how participating in student-faculty pedagogical partnerships supported two undergraduate students in expanding agentic engagement to encompass student empowerment and equity both within and beyond the classroom. We draw on the students’ autoethnographic accounts of three interrelated experiences: (1) joining a pedagogical partnership program as pedagogical consultants and developing confidence in, capacity for, and commitment to supporting student and faculty learning; (2) carrying that confidence, capacity, and commitment into the courses in which those students were enrolled to enact agentic engagement in their own and in support of others’ learning; and (3) expanding the agentic engagement they developed in the first two instances beyond classroom learning. This study has implications for classroom instruction, faculty professional development, and student advising and retention

The Number Systems Tower

For high school and college instructors and students, this paper connects number systems, field axioms, and polynomials. It also considers other properties such as cardinality, density, subset, and superset relationships. Additional aspects of this paper include gains and losses through sequences of number systems. The paper ends with a great number of activities for classroom use

Improved management of key northern region weeds: diverse problems, diverse solutions

The cropping region of northern Australia has a diverse range of cropping systems and weed flora. A fallow phase is commonly required between crops to enable the accumulation of stored soil water in these farming systems dominated by reduced tillage. During the fallow phase, weed control is important and is heavily reliant on herbicides. The most commonly used herbicide has been glyphosate. As a result of over-reliance on glyphosate, there are now seven confirmed glyphosate-resistant weeds and several glyphosate-tolerant species common in the region. As a result, the control of summer fallow weeds is become more complex. This paper outlines project work investigating improved weed control for summer fallows in the northern cropping region. Areas of research include weed ecology, chemical and non-chemical tactics, glyphosate resistance and resistance surveys. The project also has an economic and extension component. As a result of our research we have a better understanding of the ecology of major northern weeds and spread of glyphosate resistance in the region. We have identified and defined alternative herbicide and non-chemical approaches for the effective control of summer fallow weeds and have extended our research effectively to industry

The alpha1 subunit of the GABA(A) receptor modulates fear learning and plasticity in the lateral amygdala.

Synaptic plasticity in the amygdala is essential for emotional learning. Fear conditioning, for example, depends on changes in excitatory transmission that occur following NMDA receptor activation and AMPA receptor modification in this region. The role of these and other glutamatergic mechanisms have been studied extensively in this circuit while relatively little is known about the contribution of inhibitory transmission. The current experiments addressed this issue by examining the role of the GABA(A) receptor subunit alpha1 in fear learning and plasticity. We first confirmed previous findings that the alpha1 subunit is highly expressed in the lateral nucleus of the amygdala. Consistent with this observation, genetic deletion of this subunit selectively enhanced plasticity in the lateral amygdala and increased auditory fear conditioning. Mice with selective deletion of alpha1 in excitatory cells did not exhibit enhanced learning. Finally, infusion of a alpha1 receptor antagonist into the lateral amygdala selectively impaired auditory fear learning. Together, these results suggest that inhibitory transmission mediated by alpha1-containing GABA(A) receptors plays a critical role in amygdala plasticity and fear learning