506 research outputs found
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
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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]
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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
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