1,063 research outputs found
Private-label use and store loyalty
The authors develop an econometric model of the relationship between a household’s private-label (PL) share and its behavioral store loyalty. The model includes major drivers of these two behaviors and controls for simultaneity and nonlinearity in the relationship between them. The model is estimated with a unique data set that combinescomplete purchase records of a panel of Dutch households with demographic and psychographic data. The authorsestimate the model for two retail chains in the Netherlands the leading service chain with a well-differentiatedhigh-share PL and the leading value chain with a lower-share PL. They find that PL share significantly affects all three measures of behavioral loyalty in the study: share of wallet, share of items purchased, andshare of shopping trips. In addition, behavioral loyalty has a significant effect on PL share. For the service chain, the authors find that both effects are in the form of an inverted U. For the value chain, the effects are positive and nonlinear, but they do not exhibit nonmonotonicity, because PL share has not yet reached high enough levels. The managerial implications of this research are important. Retailers can reap the benefits of a virtuous cycle; greater PL share increases share of wallet, and greater share of wallet increases PL share. However, this virtuous cycle operates only to a point because heavy PL buyers tend to be loyal to price savings and PLs in general, not to the PL of any particular chain.pre-prin
Fungal Genomics Challenges the Dogma of Name-Based Biosecurity
Microorganisms have inadvertently been spread via the global movement and trade of their substrates,
such as animals, plants, and soil. This intercontinental exchange in the current era of
globalisation has given rise to significant increases in the distribution of known pests and pathogens.
Importantly, it has also resulted in many novel, emerging, infectious diseases. Biosecurity
and quarantine, which aim to prevent the establishment of foreign or harmful organisms in a
non-native area, are under significant pressure due to the massive increases in travel and trade.
Traditionally, quarantine regulations have been implemented based on pathogens that
already cause significant disease problems on congener hosts in other parts of the world (e.g.,
Q-bank, available at http://www.q-bank.eu). Well-known pathogens are described, named, and
studied to determine their disease cycle, epidemiology, and impact. Their importance is
assessed based on their risk of infection, establishment, and economic or environmental consequences.
This then shapes phytosanitary practices.The Tree
Protection Co-operative Programme (TPCP), THRIP
initiative of the Department of Trade and Industry,
Department of Science and Technology (DST)/
National Research Foundation (NRF), and Centre of
Excellence in Tree Health Biotechnology (CTHB).http://www.plospathogens.orgam2016Forestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyPlant Scienc
A meeting report: cross-cultural comparability of questionnaire measures in large-scale international surveys
The value of cross-country comparisons is at the heart of large-scale international surveys. Yet the validity of such comparisons is often challenged, particularly in the case of latent traits whose estimates are based on self-reported answers to a small number of questionnaire items. Many believe self-reports to be unreliable and not comparable, and indeed, formal statistical procedures very often reject the assumption that the questions are understood and answered in the same way in different countries (measurement invariance). A methodological conference on the comparability of questionnaire scales was hosted by the OECD on 8 and 9 November 2018. This meeting report summarises the discussions held at the conference about measurement invariance testing and instrument design. The report first provides a brief introduction to the measurement models and the accompanying invariance analyses typically used in the industry of large-scale international surveys and points to the main limitations of these current standard approaches. It then presents classical and novel ways to deal with imperfect comparability of measurements when scaling and reporting on continuous traits and on categorical latent variables. It finally discusses the extent to which item design can improve the cross-country comparability of the measured constructs (e.g. by adopting innovative item formats such as anchoring vignettes and situational judgement test items). It concludes with some general considerations for survey design and reporting on invariance analyses and survey results
Multiattribute perceptual mapping with idiosyncratic brand and attribute sets
This article proposes an extremely flexible procedure for perceptual mapping based on multiattribute ratings, such that the respondent freely generates sets of both brands and attributes. Therefore, the brands and attributes are known and relevant to each participant. Collecting and analyzing such idiosyncratic datasets can be challenging. Therefore, this study proposes a modification of generalized canonical correlation analysis to support the analysis of the complex data structure. The model results in a common perceptual map with subject-specific and overall fit measures. An experimental study compares the proposed procedure with alternative approaches using predetermined sets of brands and/or attributes. In the proposed procedure, brands are better known, attributes appear more relevant, and the respondent's burden is lower. The positions of brands in the new perceptual map differ from those obtained when using fixed brand sets. Moreover, the new procedure typically yields positioning information on more brands. An empirical study on positioning of shoe stores illustrates our procedure and resulting insights. Finally, the authors discuss limitations, potential application areas, and directions for research
Aboriginal and Torres Strait Islander Suicide in Context
Aboriginal and Torres Strait Islander suicide has been an issue of national public health and mental health concern for only one decade, having increased dramatically from levels that were very low in the late 1980s to levels of young adult male suicide that are now substantially higher than for the non-indigenous population. In this review the authors socially and historically contextualize these changes, identifying the causal frameworks adopted in developing interventions, and present an explanation in narrative and pictorial form that draws on critical family-centered trauma
H.E.S.S. observations of gamma-ray bursts in 2003-2007
Very-high-energy (VHE; >~100 GeV) gamma-rays are expected from gamma-ray
bursts (GRBs) in some scenarios. Exploring this photon energy regime is
necessary for understanding the energetics and properties of GRBs. GRBs have
been one of the prime targets for the H.E.S.S. experiment, which makes use of
four Imaging Atmospheric Cherenkov Telescopes (IACTs) to detect VHE gamma-rays.
Dedicated observations of 32 GRB positions were made in the years 2003-2007 and
a search for VHE gamma-ray counterparts of these GRBs was made. Depending on
the visibility and observing conditions, the observations mostly start minutes
to hours after the burst and typically last two hours. Results from
observations of 22 GRB positions are presented and evidence of a VHE signal was
found neither in observations of any individual GRBs, nor from stacking data
from subsets of GRBs with higher expected VHE flux according to a
model-independent ranking scheme. Upper limits for the VHE gamma-ray flux from
the GRB positions were derived. For those GRBs with measured redshifts,
differential upper limits at the energy threshold after correcting for
absorption due to extra-galactic background light are also presented.Comment: 9 pages, 4 tables, 3 figure
Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
Aims: The BL Lac object RGB J0152+017 (z=0.080) was predicted to be a very
high-energy (VHE; > 100 GeV) gamma-ray source, due to its high X-ray and radio
fluxes. Our aim is to understand the radiative processes by investigating the
observed emission and its production mechanism using the High Energy
Stereoscopic System (H.E.S.S.) experiment. Methods: We report recent
observations of the BL Lac source RGB J0152+017 made in late October and
November 2007 with the H.E.S.S. array consisting of four imaging atmospheric
Cherenkov telescopes. Contemporaneous observations were made in X-rays by the
Swift and RXTE satellites, in the optical band with the ATOM telescope, and in
the radio band with the Nancay Radio Telescope. Results: A signal of 173
gamma-ray photons corresponding to a statistical significance of 6.6 sigma was
found in the data. The energy spectrum of the source can be described by a
powerlaw with a spectral index of 2.95+/-0.36stat+/-0.20syst. The integral flux
above 300 GeV corresponds to ~2% of the flux of the Crab nebula. The source
spectral energy distribution (SED) can be described using a two-component
non-thermal synchrotron self-Compton (SSC) leptonic model, except in the
optical band, which is dominated by a thermal host galaxy component. The
parameters that are found are very close to those found in similar SSC studies
in TeV blazars. Conclusions: RGB J0152+017 is discovered as a source of VHE
gamma-rays by H.E.S.S. The location of its synchrotron peak, as derived from
the SED in Swift data, allows clearly classification it as a
high-frequency-peaked BL Lac (HBL).Comment: Accepted for publication in A&A Letters (5 pages, 4 figures
First detection of a VHE gamma-ray spectral maximum from a Cosmic source: H.E.S.S. discovery of the Vela X nebula
The Vela supernova remnant (SNR) is a complex region containing a number of
sources of non-thermal radiation. The inner section of this SNR, within 2
degrees of the pulsar PSR B0833-45, has been observed by the H.E.S.S. gamma-ray
atmospheric Cherenkov detector in 2004 and 2005. A strong signal is seen from
an extended region to the south of the pulsar, within an integration region of
radius 0.8 deg. around the position (RA = 08h 35m 00s, dec = -45 deg. 36'
J2000.0). The excess coincides with a region of hard X-ray emission seen by the
ROSAT and ASCA satellites. The observed energy spectrum of the source between
550 GeV and 65 TeV is well fit by a power law function with photon index = 1.45
+/- 0.09(stat) +/- 0.2(sys) and an exponential cutoff at an energy of 13.8 +/-
2.3(stat) +/- 4.1(sys) TeV. The integral flux above 1 TeV is (1.28 +/- 0.17
(stat) +/- 0.38(sys)) x 10^{-11} cm^{-2} s^{-1}. This result is the first clear
measurement of a peak in the spectral energy distribution from a VHE gamma-ray
source, likely related to inverse Compton emission. A fit of an Inverse Compton
model to the H.E.S.S. spectral energy distribution gives a total energy in
non-thermal electrons of ~2 x 10^{45} erg between 5 TeV and 100 TeV, assuming a
distance of 290 parsec to the pulsar. The best fit electron power law index is
2.0, with a spectral break at 67 TeV.Comment: 5 pages, 4 figures, accepted for publication in Astronomy and
Astrophysics letter
Methodological issues in cross-cultural research
Regardless of whether the research goal is to establish cultural universals or to identify and explain cross-cultural differences, researchers need measures that are comparable across different cultures when conducting cross-cultural studies. In this chapter, we describe two major strategies for enhancing cross-cultural comparability. First, we discuss a priori methods to ensure the comparability of data in cross-cultural surveys. In particular, we review findings on cross-cultural differences based on the psychology of survey response and provide suggestions on how to deal with these cultural differences in the survey design stage. Second, we discuss post hoc methods to ascertain data comparability and enable comparisons in the presence of threats to equivalence
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