The effects of job complexity and autonomy on cohesiveness in collectivistic and individualistic work groups: a cross‐cultural analysis

Increased job complexity and autonomy have often been associated with improved performance in work groups. This study examines the mediating effect of group cohesiveness. The moderating effects of individualism/collectivism on the relationship between job characteristics (both complexity and autonomy) and cohesiveness are also tested. The sample consists of 381 teams drawn from the Hong Kong and U.S. branches of an international bank. The findings indicate that an increase in job complexity and/or task autonomy will increase group cohesiveness, which subsequently translates to better performance. The positive effects of job complexity and autonomy on group cohesiveness are also found to be more prominent for individualistic rather than collectivistic work groups. The theoretical implications of the results and the limitations of the study are also discussed. Copyright © 2003 John Wiley & Sons, Ltd.     

Fourier analysis of the roll-up and merging of coherent structures in shallow mixing layers

The current study investigates the role of nonlinearity in the development of two-dimensional coherent structures (2DCS) in shallow mixing layers. A nonlinear numerical model based on the depth-averaged shallow water equations is used to investigate temporal shallow mixing layers, where the mapping from temporal to spatial results is made using the velocity at the center of the mixing layer. The flow is periodic in the stream-wise direction and the transmissive boundary conditions are used in the cross-stream boundaries to prevent reflections. The numerical results are examined with the aid of Fourier decomposition. Results show that the previous success in applying local linear theory to shallow mixing layers does not imply that the flow is truly linear. Linear stability theory is confirmed to be only valid within a short distance from the inflow boundary. Downstream of this linear region, nonlinearity becomes important for the roll-up and merging of 2DCS. While the energy required for the merging of 2DCS is still largely provided by the velocity shear, the merging mechanism is one where nonlinear mode interaction changes the velocity field of the subharmonic mode and the gradient of the along-stream velocity profile which, in turn, changes the magnitude of the energy production of the subharmonic mode by the velocity shear implicitly. The nonlinear mode interaction is associated with energy up-scaling and is consistent with the inverse energy cascade which is expected to occur in shallow shear flows. Current results also show that such implicit nonlinear interaction is sensitive to the phase angle difference between the most unstable mode and its subharmonic. The bed friction effect on the 2DCS is relatively small initially and grows in tandem with the size of the 2DCS. The bed friction also causes a decrease in the velocity gradient as the flow develops downstream. The transition from unstable to stable flow occurs when the bed friction balances the energy production. Beyond this point, the bed friction is more dominant and the 2DCS are progressively damped and eventually get annihilated. The energy production by the velocity shear plays an important role from the upstream end all the way to the point of transition to stable flow. The fact that linear stability theory is valid only for a short distance from the inflow boundary suggests that some elements of nonlinearity is incorporated in the mean velocity profile in experiments by the averaging process. The implicit nature of nonlinear interaction in shallow mixing layers and the sensitivity of the nonlinear interaction to phase angle difference between the most unstable mode and its subharmonic allows local linear theory to be successful in reproducing features of the instability such as the dominant mode of the 2DCS and its amplitude.     

Carbonyl emissions from commercial cooking sources in Hong Kong

Cooking fumes are an important carbonyl emission source, especially in a highly urbanized city, such as Hong Kong. Cooking exhaust from 15 commercial kitchens of a variety of cooking styles was sampled and analyzed for a suite of 13 carbonyl compounds. Carbonyl compositions were varied among the different cooking styles. Formaldehyde was generally the most abundant carbonyl, and its contribution to the total carbonyl amount on a molar basis ranged from 12 to 60%. Acrolein was also found to be an abundant carbonyl in the cooking exhaust. The highest contribution by acrolein to the total carbonyls was found to be 30% in the exhaust of a western-style steak restaurant. Long-chain saturated carbonyls, that is, heptanal, octanal, and nonanal, accounted for a significant fraction (> 40%) of the total carbonyls in kitchens that always used heated cooking oils. Two dicarbonyls, glyoxal and methylglyoxal, had a various presence in the cooking emissions, ranging from negligible to 10%. The presence of benzaldehyde and tolualdehyde was mostly negligible in the sampled kitchen exhaust. Annual emission rates of both individual carbonyls and total carbonyls were estimated for various types of commercial kitchens. Local-style fast-food shops contributed the highest total carbonyl emissions per year mainly because of the large number of this kind of restaurant in Hong Kong. The citywide annual emission rates of the three most toxic carbonyls, formaldehyde, acetaldehyde, and acrolein, were estimated assuming that the limited number of sampled restaurants were representative of the average restaurants. Such estimates of carbonyl emission rates were comparable to the estimated carbonyl emissions from vehicular sources, suggesting the importance of commercial cooking as a source for carbonyls in Hong Kong.     

Food additives for the synthesis of metal nanoparticles: a review

Environmental Chemistry Letters - Metal nanoparticles have found applications in many fields such as molecular diagnostics, electronic devices and environmental remediation. Nonetheless,...     

Effect of food availability on egg production and packaging in the intertidal scavenging gastropod Nassarius festivus

Individuals of the scavenging gastropod Nassarius festivus (Powys) were maintained for 12 weeks at one of the three ration levels, i.e. one meal every 2, 7 or 14 d, and the effect on growth and fecundity were determined. The number and size of egg capsules, number of eggs per capsule and the calorific value of eggs together with the egg capsules decreased as food availability decreased. The size of the eggs, however, was not affected. At the end of the experiment, the cumulative mortalities were high for individuals maintained at the high and medium ration and were 56.3% and 50%, respectively, whereas the mortality was only 16.7% at the low ration. There was no increase in the shell length but a decrease in the total wet weight for all the treatments. As food availability decreased, the proportion of consumed energy allocated to reproduction decreased from 7.2% to 1.4%. This plastic life history may be a mechanism enabling scavengers to survive in an environment of which the food availability is patchy and unpredictable. Received: 14 August 1998 / Accepted: 23 July 1999     

Air pollution perception in ten countries during the COVID-19 pandemic

As largely documented in the literature, the stark restrictions enforced worldwide in 2020 to curb the COVID-19 pandemic also curtailed the production of air pollutants to some extent. This study investigates the perception of the air pollution as assessed by individuals located in ten countries: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the USA. The perceptions towards air quality were evaluated by employing an online survey administered in May 2020. Participants (N = 9394) in the ten countries expressed their opinions according to a Likert-scale response. A reduction in pollutant concentration was clearly perceived, albeit to a different extent, by all populations. The survey participants located in India and Italy perceived the largest drop in the air pollution concentration; conversely, the smallest variation was perceived among Chinese and Norwegian respondents. Among all the demographic indicators considered, only gender proved to be statistically significant.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01574-2.     

The Ethics and Sustainability of Capture Fisheries and Aquaculture

The global seafood industry (capture fisheries and aquaculture) is a vital source of food, income, livelihoods, and culture. Seafood demand is steadily rising due to growth in the global human population, affluence, and per capita consumption. Seafood supply is also growing, despite declining wild fish stocks, with phenomenal advances in aquaculture, that is, the cultivation of aquatic organisms. Aquaculture supplied 42 % of the world’s fish in 2012 and is forecast to eclipse capture fisheries production by 2030. The balance between these two seafood production systems has profound implications for global food security, income distribution, and ecological sustainability. Here, a qualitative analysis of the ethics and sustainability of capture fisheries and aquaculture is presented. An innovative practical ethics approach is introduced which adapts the ethical matrix, a conceptual tool for analyzing the wellbeing, autonomy, and justice of different interest groups, and Rapfish, a rapid appraisal technique used to evaluate the sustainability of fisheries along six performance modalities, including ethics. Using case studies of global large- and small-scale capture fisheries and generalized carnivorous and omnivorous aquaculture systems, I show that human institutions and social actors interact in complex governance processes to influence seafood ethics and sustainability.     

Food wastes as fish feeds for polyculture of low-trophic-level fish: bioaccumulation and health risk assessments of heavy metals in the cultured fish

The major purpose of this study was to use different types of food wastes which serve as the major sources of protein to replace the fish meal used in fish feeds to produce quality fish. Two types of food waste-based feed pellets FW A (with cereals) and FW B (with cereals and meat products) and the commercial feed Jinfeng® were used to culture fingerlings of three low-trophic-level fish species: bighead carp, grass carp, and mud carp (in the ratio of 1:3:1) for 1 year period in the Sha Tau Kok Organic Farm in Hong Kong. Heavy metal concentrations in all of the fish species fed with food waste pellets and commercial pellets in Sha Tau Kok fish ponds were all below the local and international maximum permissible levels in food. Health risk assessments indicated that human consumption of the fish fed with food waste feed pellets was safe for the Hong Kong residents. The present results revealed that recycling of food waste for cultivating low-trophic-level fish (mainly herbivores and detritus feeders) is feasible, and at the same time will ease the disposal pressure of food waste, a common problem of densely populated cities like Hong Kong.