Highlights • Cognition and gait decline with normal and pathological aging. • Cognition and gait have shared anatomic substrates and brain control processes. • Cognitive impairment can predict ...incident gait impairment. • Changes in gait can predict incident cognitive impairment. • Interventions may be able to mitigate gait and cognitive decline in aging.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•We examine the effects of knowledge management on the performance of hospitality firms from three theoretical perspectives.•The complementarity and contingency perspectives performed better than the ...universalistic perspective.•Codification was found more important to performance of firms competing on cost.•Human capital was found more important to performance of firms competing on quality.•Codification and human capital were found to interact to influence customer service outcomes.
Competing theoretical perspectives regarding the effects of knowledge management (KM) on performance have underpinned past empirical studies. By explicitly surfacing and comparing three such perspectives, we contribute to the theoretical advancement of the KM field. We develop hypotheses consistent with the underlying logics of universalistic, complementarity and contingency theories and we empirically test these hypotheses to determine which is best supported. Data was collected from a sample of hospitality services firms operating in South Africa. Our results show that the universalistic perspective is less preferred. We find support for the complementarity perspective by revealing that codification and human capital KM capabilities interact to influence customer service outcomes. The contingency perspective also received support as the links between KM capabilities and performance were found to be contingent on the business strategy of the firm. Our results suggest that future researchers should explicitly acknowledge the theoretical perspective from which they are observing the performance impacts of KM and ensure that empirical tests are consistent with the logic of the selected perspective.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Proper quantification of the aerosol vertical height is
essential to constrain the atmospheric distribution and lifetime of
aerosols, as well as their impact on the environment. We use globally
...distributed, daily averaged measurements of aerosol stereo heights of fire
aerosols from the Multi-angle Imaging SpectroRadiometer (MISR) to understand the aerosol distribution. We also connect
these results with a simple plume rise model and a new multi-linear
regression model approach based on daily measurements of NO2 from OMI and CO from MOPITT to understand and model the global aerosol vertical height profile over biomass burning regions. First, plumes associated with the local dry-burning season at midlatitudes to high latitudes frequently have a substantial fraction lofted into the free troposphere and in some cases even the stratosphere. Second, plumes mainly associated with less-polluted regions in developing countries and heavily forested areas tend to stay closer to the ground, although they are not always uniformly distributed throughout the boundary layer. Third, plumes associated with more serious loadings of pollution (such as in Africa, Southeast Asia and northeast China) tend to have a substantial amount of smoke transported uniformly through the planetary boundary layer and up to around 3 km. Fourth, the regression model approach yields a better ability to reproduce the measured heights compared to the plume rise model approach. This improvement is based on a removal of the negative bias observed from the plume model approach, as well as a better ability to work under more heavily polluted conditions. However, over many regions, both approaches fail, requiring deeper work to understand the physical, chemical and dynamical reasons underlying the failure over these regions.
Consumers’ risk perception and trust are considered among the most important psychological states that influence online behavior. Despite the number of empirical studies that have explored the ...effects of trust and risk perceptions on consumer acceptance of e-services, the field remains fragmented and the posited research models are contradictory. To address this problem, we examined how trust and risk influence consumer acceptance of e-services through a meta-analysis of 67 studies, followed by tests of competing causal models. The findings confirm that trust and risk are important to e-services acceptance but that trust has a stronger effect size. We found that certain effect sizes were moderated by factors such as the consumer population under study, the type of e-service, and the object of trust under consideration. The data from the meta-analysis best supports the causal logic that positions trust as antecedent to risk perceptions. Risk partially mediates the effects of trust on acceptance.
Previous studies indicated that the meridional (northerly or southerly) wind anomalies over East China play an important role in modulating interannual variation of the winter haze pollution in the ...North China Plain (NCP) mainly via changing surface wind speed and humidity. Here, we report that the factors for the formation of the meridional wind anomalies over East China related to interannual variation of winter haze pollution experienced a significant interdecadal change around the mid‐1990s. Before the mid‐1990s, two upstream atmospheric wave trains contribute to generation of the meridional wind anomalies over East China via inducing significant geopotential height anomalies over northeast Asia. The first occurred over mid‐latitude Eurasia and propagated eastward into East Asia, resembling the East Atlantic‐west Russia (EAWR) pattern. The second propagated eastward along the subtropical Asian jet. Furthermore, during this period, the change in the intensity of East Asian trough (EAT) was closely linked with interannual variation of the winter haze variation in the NCP. By contrast, after the mid‐1990s, the atmospheric wave train along the Asian subtropical jet was not observed. Furthermore, the connection between the EAT intensity and the winter time NCP haze variation was weak. The mid‐latitude EAWR‐like pattern and the El Niño‐Southern Oscillation‐related sea surface temperature anomalies in the tropical Pacific were possible factors that explain the meridional wind anomalies over East China. Understanding the change in the atmospheric anomalies contributing to interannual variation of the haze is essential for the prediction of haze in the NCP.
The factors contributing to formation of the meridional wind anomalies over East China related to interannual variation of winter haze pollution over the North China Plain (NCP) experienced a pronounced interdecadal change around the mid‐1990s.
Before the mid‐1990s, two upstream atmospheric wave trains contribute to generation of the meridional wind anomalies over East China via inducing significant geopotential height anomalies over northeast Asia. The first occurred over mid‐latitude Eurasia and propagated eastward into East Asia. The second propagated eastward along the subtropical Asian jet. In addition, change in East Asian trough (EAT) intensity was closely connected to interannual variation of the winter NCP haze variation.
After the mid‐1990s, the atmospheric wave train along the Asian subtropical jet was not observed and connection of the EAT intensity with the winter time NCP haze variation was weak. The mid‐latitude wave train and the sea surface temperature anomalies in the tropical Pacific were possible factors that explain the meridional wind anomalies over East China.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A simultaneous analysis of 13 years of remotely sensed data of land cover, fires, precipitation, and aerosols from the MODIS, TRMM, and MISR satellites and the AERONET network over Southeast Asia is ...performed, leading to a set of robust relationships between land-use change and fire being found on inter-annual and intra-annual scales over Southeast Asia, reflecting the heavy amounts of anthropogenic influence over land-use change and fires in this region of the world. First, we find that fires occur annually, but with a considerable amount of variance in their onset, duration, and intensity from year to year, and from two separate regions within Southeast Asia. Second, we show that a simple regression model of the land-cover, fire, and precipitation data can be used to recreate a robust representation of the timing and magnitude of measured aerosol optical depth (AOD) from multiple measurements sources of this region using either 8-day (better for onset and duration) or monthly (better for magnitude) measurements, but not daily measurements. We find that the reconstructed AOD matches the timing and intensity from AERONET measurements to within 70 to 90 % and the timing and intensity of MISR measurements to within 50 to 95 %. This is a unique finding in this part of the world since cloud-covered regions are large, yet the model is still robustly capable, including over regions where no fires are observed and hence no emissions would be expected to contribute to AOD. Third, we determine that while Southeast Asia is a source region of such intense smoke emissions, portions of it are also impacted by smoke transported from other regions. There are regions in northern Southeast Asia which have two annual AOD peaks, one during the local fire season and the other, smaller peak corresponding to a combination of some local smoke sources as well as transport of aerosols from fires in southern Southeast Asia and possibly even from anthropogenic sources in South Asia. Overall, this study highlights the importance of taking into account a simultaneous use of land-use, fire, and precipitation for understanding the impacts of fires on the atmospheric loading and distribution of aerosols in Southeast Asia over both space and time. Furthermore, it highlights that there are significant advantages of using 8-day and monthly average values (instead of daily data) in order to better quantify the magnitude and timing of Southeast Asia fires.
Cross-border electronic-commerce (CBEC) is growing. However, due to differences in culture, habits, history and language among other factors, consumers in different regions may have different ...perception towards the same product information on CBEC platforms, which may lead to differences in their cognition of the product with implications for purchase intentions. Presently, little research has attempted to understand whether there are such differences between global consumers through the examination of measurement invariance (MI) in CBEC environments. By using multiple-group confirmatory factor analysis (MG-CFA), this study explored the invariance of two product information cognitions on CBEC platforms, namely product description and product awareness, among consumers in North America, Europe, Latin America and Oceania. Data was collected from users of a popular CBEC platform in China. We find no significant differences in understandings and levels of awareness of product information across the four groups of consumers.
Black carbon (BC) is an important aerosol constituent in the atmosphere and climate forcer. A good understanding of the radiative forcing of BC and associated climate feedback and response is ...critical to minimize the uncertainty in predicting current and future climate influenced by anthropogenic aerosols. One reason for this uncertainty is that current emission inventories of BC are mostly obtained from the so‐called bottom‐up approach, an approach that derives emissions based on categorized emitting sources and emission factors used to convert burning mass to emissions. In this work, we provide a first global‐scale top‐down estimation of global BC emissions, as well as an estimated error range, by using a Kalman Filter. This method uses data of both column aerosol absorption optical depth and surface concentrations from global and regional networks to constrain our fully coupled climate‐aerosol‐urban model and thus to derive an optimized estimate of BC emissions as 17.8 ± 5.6 Tg/yr, a factor of more than 2 higher than commonly used global BC emissions data sets. We further perform 22 additional optimization simulations that incorporate the known uncertain ranges of various important physical, model, and measurement parameters and still yield an optimized value within the above given range, from a low of 14.6 Tg/yr to a high of 22.2 Tg/yr. Furthermore, we show that the emissions difference between our optimized and a priori estimation is not uniform, with East Asia, Southeast Asia, and Eastern Europe underestimated, while North America is overestimated in the a priori inventory.
Key Points
First global top‐down estimation of BC Emissions and rigorous uncertainty range
Regional results show that some locations are underestimated and others overestimated
Sensitivity study shows robustness and precision of inversion estimation
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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