On the normal subgroups of SL(2, A)

AbstractLet A be a commutative ring having 2 in the stable range. Let N be a subgroup of SL(2, A) having level ideal J. It is shown that if either A is von Neumann regular or 2 is invertible in A, then N is normal in SL(2, A) if and only if N contains the commutator group H(J) = [E(2, A), L(2, A, J)]. Structure theorems for normal subgroups of SL(2, A) are deduced from this result

Polarization properties and dispersion relations for spiral resonances of a dielectric rod

Dielectric microcavities based on cylindrical and deformed cylindrical shapes have been employed as resonators for microlasers. Such systems support spiral resonances with finite momentum along the cylinder axis. For such modes the boundary conditions do not separate and simple TM and TE polarization states do not exist. We formulate a theory for the dispersion relations and polarization properties of such resonances for an infinite dielectric rod of arbitrary cross-section and then solve for these quantities for the case of a circular cross-section (cylinder). Useful analytic formulas are obtained using the eikonal (Einstein-Brillouin-Keller) method which are shown to be excellent approximations to the exact results from the wave equation. The major finding is that the polarization of the radiation emitted into the far-field is linear up to a polarization critical angle (PCA) at which it changes to elliptical. The PCA always lies between the Brewster and total-internal-reflection angles for the dielectric, as is shown by an analysis based on the Jones matrices of the spiraling rays.Comment: submitted to JOSA

My Cosey Corner Girl

https://digitalcommons.library.umaine.edu/mmb-vp/3301/thumbnail.jp

Comparison of resistance-based strain gauges and fiber bragg gratings in the presence of electromagnetic interference emitted from an electric motor

Thesis (M.S.) University of Alaska Fairbanks, 2018This thesis reports a performance analysis of resistance based strain gauges and fiber optic fiber Bragg gratings in an environment contaminated by high levels of electromagnetic interference. The obtained results are directly applicable to the development of aerospace vehicles propelled by electrical motors. An area of importance in this relatively new technology is characterizing the mechanical loadings coming off a propulsion device in a stationary setup. This characterization is usually accomplished through the utilization of load cells. The majority of the load cells used in such an application are based on measurements acquired through resistance strain gauges. However, electric motors are known to radiate electromagnetic interference (EMI), which in the case of brushless DC motors is pulsing, alternating, square waves. This EMI severely degrades the signal produced by the resistance strain gauge. This degradation is due to the gauge's metallic construction, acting as an antenna for the EMI. To evaluate the performance of alternative strain measuring methods, a load cell implementing both the resistance strain gauge and fiber Bragg grating sensor, the latter of which is immune to EMI, was designed as a test article. The load cell was calibrated and demonstrated a thrust load sensitivity of 1.93 ±0.04 lbf through the strain gauge system and 0.56 ±0.56 lbf through the fiber Bragg grating system. The device was subjected to both mechanical loading and EMI to quantify the effect of the EMI on the resistance strain gauge. Testing of the device included operating a brushless DC motor, with a coupled flywheel, attached to the load cell at a range of angular velocities from 500 to 2400 RPM. During laboratory testing the resistance strain gauge signal exhibited an important amount of signal spikes and electrical noise, introduced by the EMI contamination; the fiber Bragg grating did not. The spikes increased linearly with the speed of the motor. The electrical noise required bandpass filtering to extract the mechanical signal, which was obtained without noise in the fiber Bragg grating signal. The resistance strain gauge signal, at a maximum, had a signal to noise ratio of 0.0443; the fiber Bragg grating signal, at a minimum, had a signal to noise ratio of 2.0114. These results demonstrated the fiber Bragg grating is more applicable in an EMI contaminated environment

Monitoring Strategies for REDD+: Integrating Field, Airborne, and Satellite Observations of Amazon Forests

Large-scale tropical forest monitoring efforts in support of REDD+ (Reducing Emissions from Deforestation and forest Degradation plus enhancing forest carbon stocks) confront a range of challenges. REDD+ activities typically have short reporting time scales, diverse data needs, and low tolerance for uncertainties. Meeting these challenges will require innovative use of remote sensing data, including integrating data at different spatial and temporal resolutions. The global scientific community is engaged in developing, evaluating, and applying new methods for regional to global scale forest monitoring. Pilot REDD+ activities are underway across the tropics with support from a range of national and international groups, including SilvaCarbon, an interagency effort to coordinate US expertise on forest monitoring and resource management. Early actions on REDD+ have exposed some of the inherent tradeoffs that arise from the use of incomplete or inaccurate data to quantify forest area changes and related carbon emissions. Here, we summarize recent advances in forest monitoring to identify and target the main sources of uncertainty in estimates of forest area changes, aboveground carbon stocks, and Amazon forest carbon emissions

Integrin α5β1 and Fibronectin Regulate Polarized Cell Protrusions Required for Xenopus Convergence and Extension

SummaryBackgroundIntegrin recognition of fibronectin is required for normal gastrulation including the mediolateral cell intercalation behaviors that drive convergent extension and the elongation of the frog dorsal axis; however, the cellular and molecular mechanisms involved are unclear.ResultsWe report that depletion of fibronectin with antisense morpholinos blocks both convergent extension and mediolateral protrusive behaviors in explant preparations. Both chronic depletion of fibronectin and acute disruptions of integrin α5β1 binding to fibronectin increases the frequency and randomizes the orientation of polarized cellular protrusions, suggesting that integrin-fibronectin interactions normally repress frequent random protrusions in favor of fewer mediolaterally oriented ones. In the absence of integrin α5β1 binding to fibronectin, convergence movements still occur but result in convergent thickening instead of convergent extension.ConclusionsThese findings support a role for integrin signaling in regulating the protrusive activity that drives axial extension. We hypothesize that the planar spatial arrangement of the fibrillar fibronectin matrix, which delineates tissue compartments within the embryo, is critical for promoting productive oriented protrusions in intercalating cells

The effects of interdepartmental customer orientation on distribution center performance

Firms have begun to look internally for ways to increase external service quality. ANOVA is used to examine the effect of interdepartmental customer orientation on time, inventory, and customer service-based performance variables in distribution centers. Findings indicate that high interdepartmental customer orientation positively affects distribution center performance in terms of time-based performance measures and customer satisfaction. Interdepartmental customer orientation was found to have only a marginal affect on inventory performance. Implications of the current research for distribution centers and transportation managers are discussed along with limitations and opportunities for future research

Discovering the power of emotional intelligence and organizational identification in creating internal market-oriented supervision

Employees are better equipped to provide exceptional service when they are appropriately provided for and understand the company’s value proposition (Berry and Parasuraman, 1991). Internal market- orientation (IMO) pertains to a specific workplace environment that fosters employees who are trained and believe in the value offered by the company. Such support and development translates into higher quality service employees interacting with customers and their products (Lings, 2004). Linkages between IMO, emotional intelligence (EI) and organizational identification (OI) are evaluated within a supply chain and logistics context. Results indicate the direct influence of OI on IMO, and a supervisor’s ability to help employees manage emotions mediates the relationship between the ability of a supervisor to self-manage emotions and his or her propensity to create an internal market-orientation. An internal market-orientation is beneficial to the customer experience, and ultimately benefits the firm

Heterotic AdS_3/CFT_2 duality with (0,4) spacetime supersymmetry

We discuss the AdS_3/CFT_2 duality of a heterotic three-charge model with (0,4) target space supersymmetry. The worldsheet theory for heterotic strings on the AdS_3 x S^3/Z_N x T^4 near-horizon geometry was constructed by Kutasov, Larsen and Leigh in [hep-th/9812027]. We propose that the dual conformal field theory is given by a two-dimensional (0,4) sigma model arising on the Higgs branch of an orbifolded ADHM model. As a non-trivial consistency check of the correspondence, we find that the left- and right-moving central charges of the infrared conformal field theory agree with those predicted by the worldsheet model. Moreover, using the entropy function formalism, we show that to next-to-leading order the central charge can also be obtained from an alpha'-corrected supergravity theory.Comment: 34 pages, 2 figures, references added, to be published in Nucl. Phys.

Adherence Behavior in Subjects on Hemodialysis Is Not a Clear Predictor of Posttransplantation Adherence

© 2019 The Authors. Published by Elsevier Inc. on behalf of the International Society of Nephrology. This is an openaccess article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Introduction: Nonadherence is common in both hemodialysis (HD) and kidney transplant recipients and is a major risk factor for poor clinical outcomes. This retrospective study explored whether nonadherent HD patients become nonadherent transplant recipients. Methods: Data were collected for 88 patients from the electronic patient system at a subregional renal unit about adherence to HD regimens in the 6 months before transplantation, and for 1 year posttransplantation following return transfer to the posttransplantation clinic from the transplanting center. Pretransplantation definitions of nonadherence included whether the patients: on average, shortened their dialysis prescription by >10 minutes; shortened it by >15 minutes; missed 2 or more HD sessions; and had mean serum phosphate levels >1.8mmol/l. Posttransplantation definitions of nonadherence included mean tacrolimus levels outside 5 to 10 ng/ml; and missed 1 or more posttransplantation clinic appointments. Results: Nonadherence ranged from 25% to 42% pretransplantation and from 15.9% to 22.7% posttransplantation, depending on how it was operationalized. There was little relationship between pretransplantation data and posttransplantation adherence, with the exception of a significant relationship between pretransplantation phosphate and posttransplantation clinic attendance. Patients who had missed 1 or more transplant clinic appointments had higher mean pretransplantation phosphate levels. Nonadherent patients with high phosphate levels pretransplantation and missed clinic appointments posttransplantation were significantly younger. Conclusion: Our findings provide little support for the likelihood of a strong direct relationship between pre and posttransplantation behaviors. The findings require confirmation and further research to assess whether interventions in relation to pretransplantation adherence may enhance adherence posttransplantation and improve outcomes.Peer reviewedProo