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Search Results: 1 - 10 of 14228 matches for " Christopher Morgan "
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Moral Responsibility: The Missing Element in Educational Leadership
Christopher Vasillopulos,Morgan Denney
Higher Education Studies , 2013, DOI: 10.5539/hes.v3n2p74
Abstract: We intend to deepen the understanding of leadership in general and educational leadership in particular by an analysis of Chester Barnard’s (1938) concept of executive responsibility. By so doing we believe that we will reveal how an educational leader can foster the environment in which competent teachers can optimize their students’ learning experience. We will contend that Barnard’s (1938) theory of executive leadership and organizational effectiveness would have dealt much better with the dilemmas of Billy Budd than either Rand (1957) or Gomba (2012) and by extension would deal much better with the kind of organization either would suited to their models.
TRASER - Total Reflection Amplification of Spontaneous Emission of Radiation
Christopher B. Zachary, Morgan Gustavsson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035899
Abstract: Background and Objective Light and lasers in medical therapy have made dramatic strides since their invention five decades ago. However, the manufacture of lasers can be complex and expensive which often makes treatments limited and costly. Further, no single laser will provide the correct parameters to treat all things. Hence, laser specialists often need multiple devices to practice their specialty. A new concept is described herein that has the potential to replace many lasers and light sources with a single ‘tunable’ device. Study Design/Material and Methods This device amplifies spontaneous emission of radiation by capturing and retaining photons through total internal reflection, hence the acronym Total Reflection Amplification of Spontaneous Emission of Radiation, or TRASER. Results Specific peaks of light can be produced in a reproducible manner with high peak powers of variable pulse durations, a large spot size, and high repetition rate. Conclusion Considering the characteristics and parameters of Traser technology, it is possible that this one device would likely be able to replace the pulsed dye laser and many other light based systems.
GPR3 Stimulates Aβ Production via Interactions with APP and β-Arrestin2
Christopher D. Nelson, Morgan Sheng
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0074680
Abstract: The orphan G protein-coupled receptor (GPCR) GPR3 enhances the processing of Amyloid Precursor Protein (APP) to the neurotoxic beta-amyloid (Aβ) peptide via incompletely understood mechanisms. Through overexpression and shRNA knockdown experiments in HEK293 cells, we show that β-arrestin2 (βarr2), a GPCR-interacting scaffold protein reported to bind γ-secretase, is an essential factor for GPR3-stimulated Aβ production. For a panel of GPR3 receptor mutants, the degree of stimulation of Aβ production correlates with receptor-β-arrestin binding and receptor trafficking to endocytic vesicles. However, GPR3’s recruitment of βarr2 cannot be the sole explanation, because interaction with βarr2 is common to most GPCRs, whereas GPR3 is relatively unique among GPCRs in enhancing Aβ production. In addition to β-arrestin, APP is present in a complex with GPR3 and stimulation of Aβ production by GPR3 mutants correlates with their level of APP binding. Importantly, among a broader selection of GPCRs, only GPR3 and prostaglandin E receptor 2 subtype EP2 (PTGER2; another GPCR that increases Aβ production) interact with APP, and PTGER2 does so in an agonist-stimulated manner. These data indicate that a subset of GPCRs, including GPR3 and PTGER2, can associate with APP when internalized via βarr2, and thereby promote the cleavage of APP to generate Aβ.
Transit Target Selection Using Reduced Proper Motions
Andrew Gould,Christopher W. Morgan
Physics , 2002, DOI: 10.1086/346131
Abstract: In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of planets. For all-sky searches of bright V<~11 stars, the fraction is ~90%. We show that the great majority of these contaminants can be removed from the sample by analyzing their reduced proper motions (RPMs): giants have much lower RPMs than dwarfs of the same color. We use Hipparcos data to design a RPM selection function that eliminates most evolved stars, while rejecting only 9% of viable transit targets. Our method can be applied using existing or soon-to-be-released all-sky data to stars V<12.5 in the northern hemisphere and V<12 in the south. The method degrades at fainter magnitudes, but does so gracefully. For example, at V=14 it can still be used to eliminate giants redward of V-I~0.95, that is, the blue edge of the red giant clump.
Sex differences in microRNA regulation of gene expression: no smoke, just miRs
Morgan Christopher P,Bale Tracy L
Biology of Sex Differences , 2012, DOI: 10.1186/2042-6410-3-22
Abstract: Males and females differ widely in morphology, physiology, and behavior leading to disparities in many health outcomes, including sex biases in the prevalence of many neurodevelopmental disorders. However, with the exception of a relatively small number of genes on the Y chromosome, males and females share a common genome. Therefore, sexual differentiation must in large part be a product of the sex biased expression of this shared genetic substrate. microRNAs (miRs) are small non-coding RNAs involved in the post-transcriptional regulation of up to 70% of protein-coding genes. The ability of miRs to regulate such a vast amount of the genome with a high degree of specificity makes them perfectly poised to play a critical role in programming of the sexually dimorphic brain. This review describes those characteristics of miRs that make them particularly amenable to this task, and examines the influences of both the sex chromosome complement as well as gonadal hormones on their regulation. Exploring miRs in the context of sex differences in disease, particularly in sex-biased neurodevelopmental disorders, may provide novel insight into the pathophysiology and potential therapeutic targets in disease treatment and prevention.
Research Notes ~ Is Enough Too Much? The dilemma for online distant learner supporters
Christopher K. Morgan,Anthony D. McKenzie
International Review of Research in Open and Distance Learning , 2003,
Abstract: We are a gregarious species, so it is not surprising that distance learners can be prone to feelings of isolation. In the days of traditional print-dominant distance education, attrition rates were often higher among distance learners than for their on-campus counterparts; but now, with the wider choice of communication options afforded by the online revolution, institutions have opportunity to look afresh at ways of compensating for the loneliness of long distance learners.However, teachers in higher education have their own problems. By viewing an online program as a human activity system, we identify an issue of growing concern concerning system maintenance; specifically, how system survival depends on meeting the human needs of those involved. The authors are not only concerned for distance learners, but also learning facilitators, many of whom face their own context-induced pressures. From the case of their own institutional setting, the authors demonstrate the need to manage the twin risks of student dropout and lecturer burnout.
What about me…? The PVT: a role for the paraventricular thalamus (PVT) in drug-seeking behavior
Morgan H. James,Christopher V. Dayas
Frontiers in Behavioral Neuroscience , 2013, DOI: 10.3389/fnbeh.2013.00018
Abstract:
US Resident Perceptions of Dairy Cattle Management Practices  [PDF]
Nicole Olynk Widmar, Carissa J. Morgan, Christopher A. Wolf, Elizabeth A. Yeager, S. R. Dominick, Candace C. Croney
Agricultural Sciences (AS) , 2017, DOI: 10.4236/as.2017.87049
Abstract:
As public perception continues to shape the dairy industry, an understanding of consumer views and purchasing behaviors is critically important. The objectives of this paper are to: 1) summarize consumer perceptions or views of 12 common dairy cattle management practices (humane methods of slaughter, humane transportation, increased pen stall or size, access to pasture, feeding of a GMO-free diet, feeding of an organic diet, feeding of a diet the animal would naturally consume, ability to interact with other animals of the same species, access to fresh water at all times, tail docking, use of antibiotics for sick animals, and dehorning), and 2) analyze relationships between respondent’s household demographic characteristics and perceptions of three specific contentious dairy practices, including antibiotic use, tail docking, and dehorning. An online, national survey was used to collect data on household demographics, dairy consumption and purchasing behavior, and perceptions of dairy production practices from 1201 US residents. The findings of this study indicate that 87% of participants consumed dairy products. Of these respondents, 12% had altered their consumption of dairy products over the past three years because of animal welfare concerns and 10% had done so due to food safety concerns. Respondents perceived tail docking and dehorning to have the least beneficial and most negative implications for dairy cattle welfare of the dairy production practices considered.
Correlation of Urinary Engrailed-2 Levels to Tumour Volume and Pathological Stage in Men Undergoing Radical Prostatectomy  [PDF]
Hardev Pandha, Saqib Javed, Prasanna Sooriakumaran, Simon Bott, Bruce Montgomery, Anthony Hutton, Christopher Eden, Christopher Eden, Stephen E. Langley, Richard Morgan
Journal of Cancer Therapy (JCT) , 2013, DOI: 10.4236/jct.2013.43089
Abstract:

The aim of this study was to assess the relationship between pre-prostatectomy urinary Engrailed-2 (EN2), a transcription factor secreted by prostate cancer cells, with tumour volume and pathological characteristics in resected prostate specimens. First pass urine samples (10 ml) without prior prostatic massage were collected and stored at –80°C. EN2 levels were measured using an enzyme-linked immunoabsorbent assay. Tumour volume in the prostatectomy specimens was determined histologically. 57 men undergoing RP in one urological cancer network were evaluated. EN2 was detected in 85% of RP patients. EN2 correlated with tumour volume (but not total prostatic volume) in a linear regression analysis, with increasing pathological T stage and margin positivity. Using three cutoff levels of tumour volume (0.5 ml, 1.3 ml and 2.5 ml) to define significant disease, men with significant disease had markedly higher levels of urinary EN2 (p < 0.001 for each cut off level). Levels of urinary EN2 may be useful in predicting tumour volume in men with prostate cancer by potentially identifying men with small volume insignificant disease. This study justifies a larger multicentre evaluation of urinary EN2 levels as a biomarker of PC significance using cancer volume, pathological and PSA criteria.

The Quasar Accretion Disk Size -- Black Hole Mass Relation
Christopher W. Morgan,C. S. Kochanek,Nicholas D . Morgan,Emilio E. Falco
Physics , 2010,
Abstract: We use the microlensing variability observed for eleven gravitationally lensed quasars to show that the accretion disk size at a rest-frame wavelength of 2500 Angstroms is related to the black hole mass by log(R_{2500}/cm)=(15.78\pm0.12) + (0.80\pm0.17)\log(M_BH/10^9M_sun). This scaling is consistent with the expectation from thin disk theory (R ~ M_BH^{2/3}), but when interpreted in terms of the standard thin disk model (T ~ R^{-3/4}), it implies that black holes radiate with very low efficiency, log(eta) = -1.77\pm0.29 + log(L/L_E) where eta=L/(Mdot*c^2). Only by making the maximum reasonable shifts in the average inclination, Eddington factors and black hole masses can we raise the efficiency estimate to be marginally consistent with typical efficiency estimates (eta ~ 10%). With one exception, these sizes are larger by a factor of ~4 than the size needed to produce the observed 0.8 micron quasar flux by thermal radiation from a thin disk with the same T ~ R^{-3/4} temperature profile. While scattering a significant fraction of the disk emission on large scales or including a large fraction of contaminating line emission can reduce the size discrepancy, resolving it also appears to require that accretion disks have flatter temperature/surface brightness profiles.
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