434 research outputs found
Attrition when dropping CAPI from a CATI/CAPI panel survey
In this paper, we study attrition in a household panel survey, where in the first
wave those with a matched landline number were surveyed by telephone, while
those without received a face-to-face visit. In the second wave, the face-to-face
mode was dropped. We find among the first wave face-to-face households a high
likelihood to attrite due to "no contact" rather than due to "cannot be tracked"
or "refusal". Socio-demographic characteristics have the expected effects. For
example households with young children, with a short-term residence permit,
or one-person households cannot be tracked, while those with a face-to-face
visit in the first wave, or foreigners with a mother tongue that is not offered in
the survey refuse more often. More first wave calls and contacts are associated
with all reasons to attrite, in particular with refusal. Based on the findings, we
give recommendations to tailor fieldwork to decrease attrition
Triple-q octupolar ordering in NpO_2
We report the results of resonant X-ray scattering experiments performed at
the Np M_4,5 edges in NpO_2. Below T_0 = 25 K, the development of long-range
order of Np electric quadrupoles is revealed by the growth of superlattice
Bragg peaks. The electronic transition is not accompanied by any measurable
crystallographic distortion, either internal or external, so the symmetry of
the system remains cubic. The polarization and azimuthal dependence of the
intensity of the resonant peaks is well reproduced assuming Templeton
scattering from a triple-q longitudinal antiferroquadrupolar structure.
Electric quadrupole order in NpO_2 could be driven by the ordering at T_0 of
magnetic octupoles of Gamma_5 symmetry, splitting the Np ground state quartet
and leading to a singlet ground state with zero dipole magnetic moment.Comment: 4 Pages, 3 Figures, submitted to Phys. Rev. Lett. v2: resubmitted
after referee report
Magnetic properties of the spin-1 chain compound NiClCHCHCHNH
We report experimental results of the static magnetization, ESR and NMR
spectroscopic measurements of the Ni-hybrid compound
NiClCHCHCHNH. In this material NiCl octahedra are
structurally arranged in chains along the crystallographic -axis. According
to the static susceptibility and ESR data Ni spins are isotropic
and are coupled antiferromagnetically (AFM) along the chain with the exchange
constant K. These are important prerequisites for the realization of
the so-called Haldane spin-1 chain with the spin-singlet ground state and a
quantum spin gap. However, experimental results evidence AFM order at K presumably due to small interchain couplings. Interestingly,
frequency-, magnetic field-, and temperature-dependent ESR measurements, as
well as the NMR data, reveal signatures which could presumably indicate an
inhomogeneous ground state of co-existent mesoscopically spatially separated
AFM ordered and spin-singlet state regions similar to the situation observed
before in some spin-diluted Haldane magnets
Ligand selectivity in stabilising tandem parallel folded G-quadruplex motifs in human telomeric DNA sequences
Biophysical studies of ligand interactions with three human telomeric repeat sequences (d(AGGG(TTAGGG)n, n = 3, 7 and 11)) show that an oxazole-based ‘click’ ligand, which induces parallel folded quadruplexes, preferentially stabilises longer telomeric repeats providing evidence for selectivity in binding at the interface between tandem quadruplex motifs
How to survey displaced workers in Switzerland ? Sources of bias and ways around them
Studying career outcomes after job loss is challenging because individually displaced worker form a self-selected group. Indeed, the same factors causing the workers to lose their jobs, such as lack of motivation, may also reduce their re-employment prospects. Using data from plant closures where all workers were displaced irrespective of their individual characteristics offers a way around this selection bias. There is no systematic data collection on workers displaced by plant closure in Switzerland. Accordingly, we conducted our own survey on 1200 manufacturing workers who had lost their job 2 years earlier. The analysis of observational data gives rise to a set of methodological challenges, in particular nonresponse bias. Our survey addressed this issue by mixing data collection modes and repeating contact attempts. In addition, we combined the survey data with data from the public unemployment register to examine the extent of nonresponse bias. Our analysis suggests that some of our adjustments helped to reduce bias. Repeated contact attempts increased the response rate, but did not reduce nonresponse bias. In contrast, using telephone interviews in addition to paper questionnaires helped to substantially improve the participation of typically underrepresented subgroups. However, the survey respondents still differ from nonrespondents in terms of age, education and occupation. Interestingly, these differences have no significant impact on the substantial conclusion about displaced workers' re-employment prospects
The Swiss Household Panel Study : Observing social change since 1999
Collecting data on households and individuals since 1999, the Swiss Household Panel (SHP) is an ongoing, unique, large-scale, nationally representative, longitudinal study in Switzerland (N=7,383 households and N=12,119 persons interviewed in 2014). The data of the SHP provide a rich source of information to study social change in Switzerland over a significant period on a wide variety of topics. The SHP aims to provide both continuity and innovation in measurement and data collection, with the combination of retrospective and prospective longitudinal data in the most recent refreshment sample as one notable example of such an innovation. This paper provides an overview of the SHP – focusing on its origin, aims, design, content, data collection and adjustments, possibilities for cross-national comparisons, data use and accomplishments
On the Lagrangian Dynamics of Atmospheric Zonal Jets and the Permeability of the Stratospheric Polar Vortex
The Lagrangian dynamics of zonal jets in the atmosphere are considered, with
particular attention paid to explaining why, under commonly encountered
conditions, zonal jets serve as barriers to meridional transport. The velocity
field is assumed to be two-dimensional and incompressible, and composed of a
steady zonal flow with an isolated maximum (a zonal jet) on which two or more
travelling Rossby waves are superimposed. The associated Lagrangian motion is
studied with the aid of KAM (Kolmogorov--Arnold--Moser) theory, including
nontrivial extensions of well-known results. These extensions include
applicability of the theory when the usual statements of nondegeneracy are
violated, and applicability of the theory to multiply periodic systems,
including the absence of Arnold diffusion in such systems. These results,
together with numerical simulations based on a model system, provide an
explanation of the mechanism by which zonal jets serve as barriers to
meridional transport of passive tracers under commonly encountered conditions.
Causes for the breakdown of such a barrier are discussed. It is argued that a
barrier of this type accounts for the sharp boundary of the Antarctic ozone
hole at the perimeter of the stratospheric polar vortex in the austral spring.Comment: Submitted to Journal of the Atmospheric Science
Magnetic properties and revisited exchange integrals of the frustrated chain cuprate PbCuSO(OH) - linarite
We present a detailed study in the paramagnetic regime of the frustrated
= 1/2 spin-compound linarite, PbCuSO(OH), with competing ferromagnetic
nearest-neighbor and antiferromagnetic next-nearest-neighbor exchange
interactions. Our data reveal highly anisotropic values for the saturation
field along the crystallographic main directions, with 7.6, 10.5
and 8.5\,T for the , , and axes, respectively. In the
paramagnetic regime, this behavior is explained mainly by the anisotropy of the
\textit{g}-factor but leaving room for an easy-axis exchange anisotropy. Within
the isotropic - spin model our experimental data are described by
various theoretical approaches yielding values for the exchange interactions
-100\,K and 36\,K. These main intrachain exchange
integrals are significantly larger as compared to the values derived in two
previous studies in the literature and shift the frustration ratio 0.36 of linarite closer to the 1D critical point at 0.25.
Electron spin resonance (ESR) and nuclear magnetic resonance (NMR) measurements
further prove that the static susceptibility is dominated by the intrinsic spin
susceptibility. The Knight shift as well as the broadening of the linewidth in
ESR and NMR at elevated temperatures indicate a highly frustrated system with
the onset of magnetic correlations far above the magnetic ordering temperature
= 2.75(5)\,K, in agreement with the calculated exchange
constants.Comment: 18 pages, 18 figure
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