4,239 research outputs found
Panel design effects on response rates and response quality
To understand changes in individuals' opinions and attitudes it would be bestto collect data through panels. Such panels, however, often cause irritationamong respondents, resulting in low response rates and low response quality.We address whether this problem can be alleviated by designing a panel surveyin an alternative way. For this purpose, we perform two field studies wherewe measure the effects of several panel design characteristics on response ratesand response quality. These characteristics include the number of waves andthe time between subsequent waves, which may either be fixed or random.Our findings suggest that response rates and response quality can be im-proved significantly by surveying at random time intervals. It is then crucialthat panel members are not informed about the dates they will be surveyed,because in this case respondents are less likely to develop expectations as towhen they will be surveyed again. The methodology we put forward can be used to improve the eñciency of a panel study by carefully calibrating thestudies' panel designs parameters.nonresponse;panel conditioning;randomized sampling;time sampling;panel design
The Viking surface sampler
A surface sampler subsystem for the Viking Lander has been designed, fabricated, cleaned, and successfully tested. Testing has included component level tests to qualification environment and subsystem level tests. This development hardware has also been integrated into a System Test Bed (STB) for the lander system. In addition to the normal dynamic and thermal environments the surface sampler hardware has been tested in an aircraft to simulate the effects of the reduced Martian gravity. Although problems have been encountered with the first-build and integration, the basic design appears to be sound and hardware qualification is scheduled for late 1973
Word-level Symbolic Trajectory Evaluation
Symbolic trajectory evaluation (STE) is a model checking technique that has
been successfully used to verify industrial designs. Existing implementations
of STE, however, reason at the level of bits, allowing signals to take values
in {0, 1, X}. This limits the amount of abstraction that can be achieved, and
presents inherent limitations to scaling. The main contribution of this paper
is to show how much more abstract lattices can be derived automatically from
RTL descriptions, and how a model checker for the general theory of STE
instantiated with such abstract lattices can be implemented in practice. This
gives us the first practical word-level STE engine, called STEWord. Experiments
on a set of designs similar to those used in industry show that STEWord scales
better than word-level BMC and also bit-level STE.Comment: 19 pages, 3 figures, 2 tables, full version of paper in International
Conference on Computer-Aided Verification (CAV) 201
STARlight: A Monte Carlo simulation program for ultra-peripheral collisions of relativistic ions
Ultra-peripheral collisions (UPCs) have been a significant source of study at
RHIC and the LHC. In these collisions, the two colliding nuclei interact
electromagnetically, via two-photon or photonuclear interactions, but not
hadronically; they effectively miss each other. Photonuclear interactions
produce vector meson states or more general photonuclear final states, while
two-photon interactions can produce lepton or meson pairs, or single mesons. In
these interactions, the collision geometry plays a major role. We present a
program, STARlight, that calculates the cross-sections for a variety of UPC
final states and also creates, via Monte Carlo simulation, events for use in
determining detector efficiency.Comment: 15 pages; final version with a few minor bugs correcte
Panel design effects on response rates and response quality
To understand changes in individuals' opinions and attitudes it would be best
to collect data through panels. Such panels, however, often cause irritation
among respondents, resulting in low response rates and low response quality.
We address whether this problem can be alleviated by designing a panel survey
in an alternative way. For this purpose, we perform two field studies where
we measure the effects of several panel design characteristics on response rates
and response quality. These characteristics include the number of waves and
the time between subsequent waves, which may either be fixed or random.
Our findings suggest that response rates and respons
Can past intergroup contact shape support for policies in a pandemic? Processes predicting endorsement of discriminatory Chinese restrictions during the COVID-19 crisis
A survey of 340 UK residents was conducted when the COVID-19 virus first reached the UK in February 2020. We measured past experiences of positive and negative intergroup contact with Chinese people as predictors of intergroup threat and emotions in the context of the pandemic; and how these processes in turn predicted support for discriminatory policies designed to restrict the freedom of Chinese people in the UK. We tested a novel threat-matching hypothesis which draws upon models of outgroup-specific social perception to predict that the emotional processes underlying contact effects will depend on the specific threat posed by the outgroup. In the present epidemiological context, Chinese people posed a salient threat to individualsâ physical health and welfare. Accordingly, we show that whilst intergroup contact predicted both fear and anger towards the outgroup, the indirect effect of contact on support for Chinese restriction policies via fear was significantly stronger than the indirect effect via anger. Our findings provide a more nuanced understanding of how specific threat and emotions drive intergroup contact effects, and offer important insights for efforts to maintain positive intergroup relations in the face of the crisis
A Robust and Scalable Continuous Flow Process for Glycerol Carbonate
We report a robust continuous flow procedure for the synthesis of glycerol carbonate (2âGLC) from green reagents glycerol and dimethyl carbonate (DMC), mediated by an inexpensive polymerâsupported base catalyst using methanol as coâsolvent. High conversion and selectivity were obtained, while residence times were typically shorter than 10 minutes
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