Optimizing signal-to-error ratio in standing wave ultrasonic measurements

Standing wave ultrasonic techniques for the measurement of very small changes in acoustic attenuation and phase velocity are discussed. Enhanced sensitivity to these small changes was achieved by making the specimen part of a composite ultrasonic resonator. It was found that a point of maximum sensitivity on the response of such an ultrasonic resonator need not coincide with a point of maximum signal-to-error ratio. A model is presented and analyzed which takes into account error due to long term (low frequency) noise effects such as gain drifts and dc level shifts. This model yields a quantitative value for the signal-to-error ratio in which the signal is defined as the ideal change in the monitored response and the error as the difference between the experimentally measured change and the signal. The specific frequency dependent forms for the ultrasonic response and the sensitivity enhancement factor were used to predict the operating point on a mechanical resonance corresponding to maximum signal-to-error ratio

The Arizona Range Cattle Market Report: An Experiment in Country-Sale Reporting

This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]

The Importance of Agricultural Production in Maricopa County, Arizona, Economy

This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]

Studies of Paleozoic fungi. IV. Wall ultrastructure of fossil endogonaceous chlamydospores

Fossil endogonaceous chlamydospores are described from the aerial axes and roots of several Paleozoic plants preserved in calcilutite nodules and calcareous coal balls. Specimens come from six Paleozoic localities extending from the uppermost Lower Devonian through the Upper Pennsylvanian. Although fossil chlamydospores are markedly similar to the modern Endogonaceae in transmitted light, ultrastructural comparisons have not previously been made. The fine structure of the walls of these spores is consistent with past interpretations which relate them to the modern Endogonaceae, but thorough comparisons cannot be made due to the lack of comparable ultrastructural information from extant VA mycorrhizae. The evidence from mycorrhizal associations in the fossil record is evaluated

Promoviendo la justicia social a través del aprendizaje-servicio en la formación de maestros de Educación Infantil

As early childhood teacher education programs have begun to place greater emphasis on standards and accountability, there has been less focus on working with the community, and especially working on important social justice issues (Kroll, 2013). In this paper we argue that integrating service-learning and teacher education is a strategy for increasing awareness of social justice issues for young children, age three to grade three. Through the use of questionnaires and interviews to collect our data, we found that implementing a cascading service-learning model in teacher education programs has a positive transformative effect on Pre-Service Teachers. Additionally, we examined the effects of social justice service-learning projects on young children. The results from the data indicated that implementing a social justice service-learning project with these participants had a great impact or transformation on them.Como en los programas de formación del profesorado para la primera infancia han empezado a poner mayor énfasis en los estándares y la rendición de cuentas, se está haciendo menos hincapié en el trabajo con la comunidad, y especialmente en trabajos centrados en temas relevantes de justicia social (Kroll, 2013). En este artículo se argumenta que la integración del aprendizaje-servicio y la formación del profesorado es una estrategia para aumentar la conciencia sobre temas de justicia social con los niños pequeños, desde los tres años hasta tercer grado. A través del uso de cuestionarios y entrevistas para la recolección de datos, se encontró que la implementación de un modelo de aprendizaje-servicio en cascada en los programas de formación del profesorado tiene un efecto transformador positivo en profesores en formación. Además, se examinaron los efectos de los proyectos de aprendizaje-servicio de justicia social con niños pequeños. Los resultados de los datos indican que la implementación de un proyecto de aprendizaje-servicio de justicia social con estos participantes tiene un gran impacto o transformación en ellos.Os programas de formação do professorado para a primeira infância começaram a pôr maior ênfase nos padrões e a prestação de contas, dando-se menos ênfase ao trabalho com a comunidade, e especialmente em trabalhos centrados em temas relevantes de justiça social (Kroll, 2013). Neste artigo se argumenta que a integração do aprendizagem-serviço e a formação do professorado é uma estratégia para aumentar a consciência sobre temas de justiça social com as crianças pequenas, desde os três anos até o terceiro grau. Através do uso de questionário e entrevistas para a coleta de dados, encontrou-se que a implementação de um modelo de aprendizagem-serviço em cascata nos programas de formação de professores tem um efeito transformador positivo em professores em formação. Ademais, examinaramse os efeitos dos projetos de aprendizagem-serviço de justiça social com crianças pequenas. Os resultados dos dados indicam que a implantação de um projeto de aprendizagem-serviço de justiça social com estes participantes causa neles um grande impacto ou transformação

Denying renal transplantation to an adolescent medical cannabis user: An ethical case study

Medical cannabis is now legal in over half of the United States. As more patients adopt this unconventional therapy, it is inevitable that potential transplant recipients will disclose their cannabis use during transplant evaluation. Transplant teams are tasked with the decision to utilize a pressure resource, often with little guidance from international and national professional organizations. Many healthcare providers remain uniformed or misinformed about the risks of cannabis use and organ transplantation. In order to illustrate the multifaceted and complex evaluation of transplant patients using medical cannabis, this article presents the case of a 20‐year‐old woman recommended for renal transplant who was originally denied active listing due to her medical cannabis use. A review of the literature explores the perceived and actual risks of cannabis use in the immunocompromised patient. Furthermore, a discussion of the ethics of medical cannabis use and organ transplantation is included with recommendations for multidisciplinary transplant teams.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150568/1/petr13467.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150568/2/petr13467_am.pd

IFN-γ and PPARδ Influence the Efficacy and Retention of Multipotent Adult Progenitor Cells in Graft vs Host Disease

Cell-based therapy for the treatment of inflammatory disorders has focused on the application of mesenchymal stromal cells (MSCs) and multipotent adult progenitor cells (MAPCs). Despite the recent positive findings in industry-sponsored clinical trials of MSCs and MAPCs for graft vs host disease (GvHD), cell therapy is efficacious in some but not all patients, highlighting the need to identify strategies to enhance cell-based therapeutic efficacy. Here, we demonstrate the capacity for interferon (IFN)-γ licensing to enhance human MAPC efficacy and retention following early administration in a humanized mouse model of acute GvHD (aGvHD). Activation of the nuclear receptor peroxisome proliferator-activated receptor delta (PPARδ) negatively influenced the retention and efficacy of human MAPCs as well as IFNγ-licensed MAPCs in the aGvHD model. PPARδ antagonism significantly enhanced the efficacy of human MAPCs when administered early in the humanized aGvHD model. COX-2 expression in human MAPC was significantly decreased in IFN-γ licensed MAPCs exposed to a PPARδ agonist. Importantly, MAPC exposure to the PPARδ antagonist in the presence of a COX-2 inhibitor indomethacin before administration significantly reduced the efficacy of PPARδ antagonized MAPCs in the aGvHD humanized mouse model. This is the first study to demonstrate the importance of PPARδ in human MAPC efficacy in vivo and highlights the importance of understanding the disease microenvironment in which cell-based therapies are to be administered. In particular, the presence of PPARδ ligands may negatively influence MAPC or MSC therapeutic efficacy

Astrocyte-mediated short-term synaptic depression in the rat hippocampal CA1 area: two modes of decreasing release probability

<p>Abstract</p> <p>Background</p> <p>Synaptic burst activation feeds back as a short-term depression of release probability at hippocampal CA3-CA1 synapses. This short-term synaptic plasticity requires functional astrocytes and it affects both the recently active (< 1 s) synapses (post-burst depression) as well as inactive neighboring synapses (transient heterosynaptic depression). The aim of this study was to investigate and compare the components contributing to the depression of release probability in these two different scenarios.</p> <p>Results</p> <p>When tested using paired-pulses, following a period of inactivity, the transient heterosynaptic depression was expressed as a reduction in the response to only the first pulse, whereas the response to the second pulse was unaffected. This selective depression of only the first response in a high-frequency burst was shared by the homosynaptic post-burst depression, but it was partially counteracted by augmentation at these recently active synapses. In addition, the expression of the homosynaptic post-burst depression included an astrocyte-mediated reduction of the pool of release-ready primed vesicles.</p> <p>Conclusions</p> <p>Our results suggest that activated astrocytes depress the release probability via two different mechanisms; by depression of vesicular release probability only at inactive synapses and by imposing a delay in the recovery of the primed pool of vesicles following depletion. These mechanisms restrict the expression of the astrocyte-mediated depression to temporal windows that are typical for synaptic burst activity.</p