Greer, Charles

HQ. 13th Bnhttps://dh.howard.edu/prom_members/1033/thumbnail.jp

Webinar: Improving Recreational Trail Accessibility with a Volcanic Ash Treatment

Recreational trails serve as valuable transportation corridors and support the health of users. Wheelchair accessibility of recreational trails depends on a variety of conditions, including slope, cross-slope, and surface characteristics. This project focused on improving the firmness and stability of a 0.2-mile section of trail that was otherwise accessible. The existing trail surface consisted of loose ¼” off-specification aggregate on native soil. A volcanic ash-Portland cement binder, studied in prior research, was batched, distributed, mixed, wetted, and compacted on site to improve the firmness and stability of the surface resulting in a smoother surface with less rolling resistance. The webinar will present details of the trail conditions, materials, batching, placement, and surface characteristics before and after treatment.https://pdxscholar.library.pdx.edu/trec_webinar/1079/thumbnail.jp

Resurfacing a Trail in Oregon Using Volcanic Ash

In the latest instance of taking research to practice, researchers at Oregon Tech have completed a pilot section of trail using a NITC-developed sustainable paving method. A quarter-mile section of the Klamath Geo Trail, just east and up the hill from the Oregon Tech Klamath Falls campus, has been successfully resurfaced using volcanic ash from Mount Mazama

Dendritic Branching of Olfactory Bulb Mitral and Tufted Cells: Regulation by TrkB

Projection neurons of mammalian olfactory bulb (OB), mitral and tufted cells, have dendrites whose morphologies are specifically differentiated for efficient odor information processing. The apical dendrite extends radially and arborizes in single glomerulus where it receives primary input from olfactory sensory neurons that express the same odor receptor. The lateral dendrites extend horizontally in the external plexiform layer and make reciprocal dendrodendritic synapses with granule cells, which moderate mitral/tufted cell activity. The molecular mechanisms regulating dendritic development of mitral/tufted cells is one of the unsolved important problems in the olfactory system. Here, we focused on TrkB receptors to test the hypothesis that neurotrophin-mediate mechanisms contributed to dendritic differentiation of OB mitral/tufted cells.With immunohistochemical analysis, we found that the TrkB neurotrophin receptor is expressed by both apical and lateral dendrites of mitral/tufted cells and that expression is evident during the early postnatal days when these dendrites exhibit their most robust growth and differentiation. To examine the effect of TrkB activation on mitral/tufted cell dendritic development, we cultured OB neurons. When BDNF or NT4 were introduced into the cultures, there was a significant increase in the number of primary neurites and branching points among the mitral/tufted cells. Moreover, BDNF facilitated filopodial extension along the neurites of mitral/tufted cells.In this report, we show for the first time that TrkB activation stimulates the dendritic branching of mitral/tufted cells in developing OB. This suggests that arborization of the apical dendrite in a glomerulus is under the tight regulation of TrkB activation

Toward a precarious projectariat? Project dynamics in Slovenian and French social services

Project organization is used extensively to promote creativity, innovation and responsiveness to local context, but can lead to precarious employment. This paper compares European Social Fund (ESF)-supported projects supporting ‘active inclusion’ of disadvantaged clients in Slovenia and France. Despite many similarities between the two social protection fields in task, temporality, teams and socio-economic context, the projects had different dynamics with important implications for workers. In Slovenia project dynamics have been precarious, leading to insecure jobs and reduced status for front-line staff; in France, by contrast, projects and employment have been relatively stable. Our explanation highlights the transaction, more specifically, the capacity of government agencies to function as intermediaries managing the transactions through which ESF money is disbursed to organizations providing services. We find that transnational pressures on the state affect its capacity as a transaction organizer to stabilize the organizational field. In Slovenia, transnational pressures associated with austerity and European Union integration have stripped away this capacity more radically than in France, leading to precarious project dynamics and risk shifting onto project workers

ACCELERATION OF ELITE ICE HOCKEY PLAYERS

The ability to accelerate quickly from a stationary or "gliding" position is an important element of Ice Hockey performance. American skaters have typically been characterized as "slow" relative to their international opponents and therefore, this study was undertaken to identify the biomechanical factors which contribute to acceleration performance

Olfactory ensheathing cell membrane properties are shaped by connectivity

Olfactory ensheathing cells (OECs) have been repeatedly implicated in mediating plasticity, particularly in situ in the olfactory nerve where they support the extension of olfactory sensory neuron (OSNs) axons from the olfactory epithelium to the olfactory bulb (OB). OECs are specialized glia whose processes surround OSN axon fascicles within the olfactory nerve and across the OB surface. Despite their purported importance in promoting axon extension, and following transplants, little is known about either morphology or biophysical properties of OECs in situ. In particular, cell-cell interactions that may influence OEC function are largely unexplored. Here, we studied OEC connectivity and morphology in slice preparations, preserving tissue structure and cell-cell interactions. Our analyses showed that OECs form a matrix of cellular projections surrounding axons, unique among glia, and express high levels of connexin-43. Lucifer Yellow injections revealed selective dye coupling among small subgroups of OECs. Two types of OECs were biophysically distinguished with whole cell voltage clamp recordings: 1) with low input resistance (Ri), linear current profiles, and frequently dye coupled; and 2) with high Ri, non-linear current profiles, and infrequent dye coupling. Pharmacological blockade of gap junctions changed OEC membrane properties such that linear OECs became non-linear. Double recordings indicated that the appearance of the non-linear current profile was associated with the loss of electrical coupling between OECs. We conclude that the diversity of OEC current profiles can be explained by differences in gap junction connectivity and discuss implications of this diversity for OEC influences on axon growth and excitability.Fil: Rela, Lorena. University of Yale; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bordey, Angelique. University of Yale; Estados UnidosFil: Greer, Charles A.. University of Yale; Estados Unido

Applying a Mt. Mazama Volcanic Ash Treatment as a Trail Accessibility Improvement

A procedure has been developed for implementing a topically applied Mt. Mazama volcanic ash trail surface amendment for improving trail firmness and stability. This project involved implementation of previously conducted Mt. Mazama volcanic research by applying a Mazama Ash and Portland Cement solution over a 0.2-mile section of the Geo Trail at the Oregon Institute of Technology Klamath Falls campus. Testing was performed to verify ideal Ash-to-Cement-to-Water ratios. A procedure was developed and applied for batching and mixing the dry materials on-site, spreading and integrating the dry material with the existing trail surface, and wetting and compacting the surface. After the pilot application, visual inconsistencies were observed in the treated trail surface. Firmness and stability were measured at different locations along the treated trail surface and on the untreated surface with a rotational penetrometer apparatus. Roughness was quantified using a modified Wheelchair Pathway Roughness Index at different locations along the treated rail surface and on the untreated surface. At each of the testing locations on the treated surface, stability was shown to have improved, firmness was relatively consistent, and the ability to roll an occupied wheelchair without rutting was markedly improved

The state and class discipline: European labour market policy after the financial crisis

This paper looks at two related labour market policies that have persisted and even proliferated across Europe both before and after the financial crisis: wage restraint, and punitive workfare programmes. It asks why these policies, despite their weak empirical records, have been so durable. Moving beyond comparative-institutionalist explanations which emphasise institutional stickiness, it draws on Marxist and Kaleckian ideas to argue that, under financialisation, the state has been pushed to adopt disciplinary and destabilising policies which target the working class, as a means of bolstering the ‘confidence’ of capitalists in the short term. Wage restraint and punitive active labour market policies are two examples of such measures. We argue that this process is not embedded in existing institutions, but actively disrupts or subverts them