1,767 research outputs found
Container seal for dusty environment
Method maintains cleanliness of joint-sealing surfaces under dust-laden conditions. This is accomplished by keeping seal and sealing surface covered with sliding plastic rings, which slide out of the way when a joint is seated
Calibrating and Stabilizing Spectropolarimeters with Charge Shuffling and Daytime Sky Measurements
Well-calibrated spectropolarimetry studies at resolutions of 10,000 with
signal-to-noise ratios (SNRs) better than 0.01\% across individual line
profiles, are becoming common with larger aperture telescopes.
Spectropolarimetric studies require high SNR observations and are often limited
by instrument systematic errors. As an example, fiber-fed spectropolarimeters
combined with advanced line-combination algorithms can reach statistical error
limits of 0.001\% in measurements of spectral line profiles referenced to the
continuum. Calibration of such observations is often required both for
cross-talk and for continuum polarization. This is not straightforward since
telescope cross-talk errors are rarely less than 1\%. In solar
instruments like the Daniel K. Inouye Solar Telescope (DKIST), much more
stringent calibration is required and the telescope optical design contains
substantial intrinsic polarization artifacts. This paper describes some
generally useful techniques we have applied to the HiVIS spectropolarimeter at
the 3.7m AEOS telescope on Haleakala. HiVIS now yields accurate polarized
spectral line profiles that are shot-noise limited to 0.01\% SNR levels at our
full spectral resolution of 10,000 at spectral sampling of 100,000. We
show line profiles with absolute spectropolarimetric calibration for cross-talk
and continuum polarization in a system with polarization cross-talk levels of
essentially 100\%. In these data the continuum polarization can be recovered to
one percent accuracy because of synchronized charge-shuffling model now working
with our CCD detector. These techniques can be applied to other
spectropolarimeters on other telescopes for both night and day-time
applications such as DKIST, TMT and ELT which have folded non-axially symmetric
foci.Comment: Accepted to A&
The Origin of Double-Peaked Narrow Lines in Active Galactic Nuclei III: Feedback from Biconical AGN Outflows
We apply an analytic Markov Chain Monte Carlo model to a sample of 18
AGN-driven biconical outflows that we identified from a sample of active
galaxies with double-peaked narrow emission lines at z < 0.1 in the Sloan
Digital Sky Survey. We find that 8/18 are best described as asymmetric bicones,
8/18 are nested bicones, and 2/18 are symmetric bicones. From the geometry and
kinematics of the models, we find that these moderate-luminosity AGN outflows
are large and energetic. The biconical outflows axes are randomly oriented with
respect to the photometric major axis of the galaxy, implying a randomly
oriented and clumpier torus to collimate the outflow, but the torus also allows
some radiation to escape equatorially. We find that 16/18 (89%) outflows are
energetic enough to drive a two-staged feedback process in their host galaxies.
All of these outflows geometrically intersect the photometric major axis of the
galaxy, and 23% of outflow host galaxies are significantly redder or have
significantly lower specific star formation rates when compared to a matched
sample of active galaxies.Comment: 32 pages, 11 figures, accepted for publication in MNRAS; See Figure 7
for a summary of the finding
Observational Constraints on General Relativistic Energy Conditions, Cosmic Matter Density and Dark Energy from X-Ray Clusters of Galaxies and Type-Ia Supernovae
New observational constraints on the cosmic matter density and an
effectively redshift-independent equation of state parameter of the dark
energy are obtained while simultaneously testing the strong and null energy
conditions of general relativity on macroscopic scales. The combination of
REFLEX X-ray cluster and type-Ia supernova data shows that for a flat Universe
the strong energy condition might presently be violated whereas the null energy
condition seems to be fulfilled. This provides another observational argument
for the present accelerated cosmic expansion and the absence of exotic physical
phenomena related to a broken null energy condition. The marginalization of the
likelihood distributions is performed in a manner to include a large fraction
of the recently discussed possible systematic errors involved in the
application of X-ray clusters as cosmological probes. This yields for a flat
Universe, and
( errors without cosmic variance). The scatter in the different
analyses indicates a quite robust result around , leaving little room
for the introduction of new energy components described by quintessence-like
models or phantom energy. The most natural interpretation of the data is a
positive cosmological constant with $w_x=-1 or something like it.Comment: 11 pages, 5 figures, Astron. Astrophys. (in press
How Fairness Garners Loyalty in the Pharmaceutical Supply Chain: Role of Trust in the Wholesaler-Pharmacy Relationship
Purpose
â The purpose of this paper is to understand how fairness garners loyalty by breeding trust in the pharmaceutical wholesalerâpharmacy relationship. Specifically, the paper seeks to understand if the two dimensions of fairness â procedural and distributive â contribute differently in fostering the two types of trust â credibility and benevolence. The paper further aims to examine how the two dimensions of trust mediate the fairnessâloyalty relationship.
Design/methodology/approach
â Data from 156 retail pharmacies on their relationship with the pharmaceutical wholesalers are used to test the hypotheses. The mediation models are tested using the Barron and Kenny procedure.
Findings
â The findings of this paper show the importance of both procedural and distributive aspects of fairness on the part of pharmaceutical wholesalers as perceived by the pharmacies. Each aspect of fairness plays a more prominent role for fostering a particular type of trust, which, in turn, leads to loyalty.
Research limitations/implications
â Future research may investigate the antecedents to fairness to unearth additional insights as to how organizations can manage their customers\u27 perceptions of fairness and thereby enhance their trust and loyalty.
Practical implications
â Pharmaceutical wholesale is a competitive business to retain pharmacies by building loyalty thus balancing pharmacies\u27 dependence on the more powerful pharmaceutical manufacturers in the pharmaceutical supply chain. Given the intense competition, the wholesaler that does a superior job in creating a competitive advantage leveraging fairness to engender trust will get to benefit in recruiting and retaining more pharmacies.
Originality/value
â This paper contributes to the fairnessâtrustâloyalty stream of literature by examining the mediation effects at the subâdimension level of the fairness and trust constructs. The paper also has practical implications, especially given the low gross margins for pharmaceutical wholesalers and the growing threat of direct distribution of pharmaceuticals or disintermediation by the manufacturers using third party logistics companies, such as united parcel service. The paper shows how wholesalers may be able to build loyalty with the pharmacies by signaling fairness and fostering trust
Online Resources Platform for Mathematics Education
The aim of this project was to develop and explore the use of a Sharable Content Object Reference Model (SCORM) integrating a web-based platform for the study of mathematics as part of an active learning environment. The platform was designed to provide active support to engineering students especially those in their first year of study. Early use of the platform can identify possible areas of weakness and provide the self-learning environment required for students to become more proficient in areas where they are lacking key skills or are finding the concepts difficult to understand. The platform consists of a set of tests and applications for the study of engineering mathematics. The tests can adapt and change depending on the answers provided by the student, including video feedback for incorrect answers before the student progresses to the next question. Based on the idea that teaching a concept is the best way to learn that concept, the students become actively involved in the platform as they create the videos that provide feedback to the other users of the platform. This active learning, constructivist approach provides an environment of achievement and ownership that allows students of all levels to enjoy the learning experience
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