Africa Meets America: The Impact of Collectivism and Individualism on Attitude towards Shopping

The adoption of marketing strategy does not occur in cultural vacuums. Instead, marketing strategies unfold within social contexts that encode values, beliefs, and patterns of behavior. The increasingly inter-dependent global economy results in the acculturation of tensions between global and local consumer cultures. This dynamism however offers new opportunities for international firms to redefine and reevaluate their glocal (global/local) marketing strategies. Relying on Triandis cultural dimensions, this research contributes to international marketing literature by answering two key research questions, namely, what are the differences between African (Ghanaian) and American consumers’ cultural characteristics? and how do the cultural differences explain attitude towards shopping behavior? The results of the study demonstrate, contrary to the literature, that Ghanaians, unlike Americans, exhibit a fusion of collectivism and individualism. Further, while both individualism and collectivism cultural traits positively and significantly impact attitude towards shopping, the extent to which culture impacts attitude towards shopping is higher in the American consumer sample than in the Ghanaian consumer sample. The authors discuss implications for international marketing practice

Engineering of xylose reductase and overexpression of xylitol dehydrogenase and xylulokinase improves xylose alcoholic fermentation in the thermotolerant yeast Hansenula polymorpha

<p>Abstract</p> <p>Background</p> <p>The thermotolerant methylotrophic yeast <it>Hansenula polymorpha </it>is capable of alcoholic fermentation of xylose at elevated temperatures (45 – 48°C). Such property of this yeast defines it as a good candidate for the development of an efficient process for simultaneous saccharification and fermentation. However, to be economically viable, the main characteristics of xylose fermentation of <it>H. polymorpha </it>have to be improved.</p> <p>Results</p> <p>Site-specific mutagenesis of <it>H. polymorpha XYL1 </it>gene encoding xylose reductase was carried out to decrease affinity of this enzyme toward NADPH. The modified version of <it>XYL1 </it>gene under control of the strong constitutive <it>HpGAP </it>promoter was overexpressed on a <it>Δxyl1 </it>background. This resulted in significant increase in the K_Mfor NADPH in the mutated xylose reductase (K341 → R N343 → D), while K_Mfor NADH remained nearly unchanged. The recombinant <it>H. polymorpha </it>strain overexpressing the mutated enzyme together with native xylitol dehydrogenase and xylulokinase on <it>Δxyl1 </it>background was constructed. Xylose consumption, ethanol and xylitol production by the constructed strain were determined for high-temperature xylose fermentation at 48°C. A significant increase in ethanol productivity (up to 7.3 times) was shown in this recombinant strain as compared with the wild type strain. Moreover, the xylitol production by the recombinant strain was reduced considerably to 0.9 mg × (L × h)^-1as compared to 4.2 mg × (L × h)^-1for the wild type strain.</p> <p>Conclusion</p> <p>Recombinant strains of <it>H. polymorpha </it>engineered for improved xylose utilization are described in the present work. These strains show a significant increase in ethanol productivity with simultaneous reduction in the production of xylitol during high-temperature xylose fermentation.</p

Metabolic engineering and classical selection of the methylotrophic thermotolerant yeast Hansenula polymorpha for improvement of high-temperature xylose alcoholic fermentation

BACKGROUND: The methylotrophic yeast, Hansenula polymorpha is an industrially important microorganism, and belongs to the best studied yeast species with well-developed tools for molecular research. The complete genome sequence of the strain NCYC495 of H. polymorpha is publicly available. Some of the well-studied strains of H. polymorpha are known to ferment glucose, cellobiose and xylose to ethanol at elevated temperature (45 – 50°C) with ethanol yield from xylose significantly lower than that from glucose and cellobiose. Increased yield of ethanol from xylose was demonstrated following directed metabolic changes but, still the final ethanol concentration achieved is well below what is considered feasible for economic recovery by distillation. RESULTS: In this work, we describe the construction of strains of H. polymorpha with increased ethanol production from xylose using an ethanol-non-utilizing strain (2EthOH(−)) as the host. The transformants derived from 2EthOH(−) overexpressing modified xylose reductase (XYL1m) and native xylitol dehydrogenase (XYL2) were isolated. These transformants produced 1.5-fold more ethanol from xylose than the original host strain. The additional overexpression of XYL3 gene coding for xylulokinase, resulted in further 2.3-fold improvement in ethanol production with no measurable xylitol formed during xylose fermentation. The best ethanol producing strain obtained by metabolic engineering approaches was subjected to selection for resistance to the known inhibitor of glycolysis, the anticancer drug 3-bromopyruvate. The best mutant selected had an ethanol yield of 0.3 g/g xylose and produced up to 9.8 g of ethanol/l during xylose alcoholic fermentation at 45°C without correction for ethanol evaporation. CONCLUSIONS: Our results indicate that xylose conversion to ethanol at elevated temperature can be significantly improved in H. polymorpha by combining methods of metabolic engineering and classical selection

Specificity and Mechanism of Mandelamide Hydrolase Catalysis

The best-studied amidase signature (AS) enzyme is probably fatty acid amide hydrolase (FAAH). Closely related to FAAH is mandelamide hydrolase (MAH), whose substrate specificity and mechanism of catalysis are described in this paper. First, we developed a convenient chromogenic substrate, 4-nitrophenylacetamide, for MAH. The lack of reactivity of MAH with the corresponding ethyl ester confirmed the very limited size of the MAH leaving group site. The reactivity of MAH with 4-nitrophenyl acetate and methyl 4-nitrophenyl carbonate, therefore, suggested formation of an “inverse” acyl-enzyme where the small acyl-group occupies the normal leaving group site. We have interpreted the specificity of MAH for phenylacetamide substrates and small leaving groups in terms of its active site structure, using a homology model based on a FAAH crystal structure. The relevant structural elements were compared with those of FAAH. Phenylmethylboronic acid is a potent inhibitor of MAH (Ki = 27 nM), presumably because it forms a transition state analogue structure with the enzyme. O-Acyl hydroxamates were not irreversible inactivators of MAH but some were found to be transient inhibitors

The VIMOS Public Extragalactic Redshift Survey (VIPERS) : The decline of cosmic star formation: quenching, mass, and environment connections

RT acknowledges financial support from the European Research Council through grant n. 202686.We use the final data of the VIMOS Public Extragalactic Redshift Survey (VIPERS) to investigate the effect of the environment on the evolution of galaxies between z = 0.5 and z = 0.9. We characterise local environment in terms of the density contrast smoothed over a cylindrical kernel, the scale of which is defined by the distance to the fifth nearest neighbour. This is performed by using a volume-limited sub-sample of galaxies complete up to z = 0.9, but allows us to attach a value of local density to all galaxies in the full VIPERS magnitude-limited sample to i < 22.5. We use this information to estimate how the distribution of galaxy stellar masses depends on environment. More massive galaxies tend to reside in higher-density environments over the full redshift range explored. Defining star-forming and passive galaxies through their (NUV-r) vs. (r-K) colours, we then quantify the fraction of star-forming over passive galaxies, fap, as a function of environment at fixed stellar mass. fap is higher in low-density regions for galaxies with masses ranging from log (M/M⊙) = 10.38 (the lowest value explored) to at least log (M/M⊙) ~ 11.3, although with decreasing significance going from lower to higher masses. This is the first time that environmental effects on high-mass galaxies are clearly detected at redshifts as high as z ~ 0.9. We compared these results to VIPERS-like galaxy mock catalogues based on a widely used galaxy formation model. The model correctly reproduces fap in low-density environments, but underpredicts it at high densities. The discrepancy is particularly strong for the lowest-mass bins. We find that this discrepancy is driven by an excess of low-mass passive satellite galaxies in the model. In high-density regions, we obtain a better (although not perfect) agreement of the model fap with observations by studying the accretion history of these model galaxies (that is, the times when they become satellites), by assuming either that a non-negligible fraction of satellites is destroyed, or that their quenching timescale is longer than ~ 2 Gyr.PostprintPeer reviewe

The VIMOS Public Extragalactic Redshift Survey (VIPERS). Downsizing of the blue cloud and the influence of galaxy size on mass quenching over the last eight billion years

R.T. acknowledges financial support from the European Research Councilthrough grant No. 202686.We use the full VIPERS redshift survey in combination with SDSS-DR7 to explore the relationships between star-formation history (using d4000), stellar mass and galaxy structure, and how these relationships have evolved since z ~ 1. We trace the extents and evolutions of both the blue cloud and red sequence by fitting double Gaussians to the d4000 distribution of galaxies in narrow stellar mass bins, for four redshift intervals over 0 < z < 1. This reveals downsizing in star formation, since the high-mass limit of the blue cloud has retreated steadily from time from ℳ ~ 1011.2 M⊙ at z ~ 0.9 to ℳ ~ 1010.7 M⊙ to the present day. The number density of massive blue-cloud galaxies (ℳ ~ 1011 M⊙, d4000 < 1.55) drops sharply by a factor five between z ~ 0.8 and z ~ 0.5. These galaxies are becoming quiescent at a rate that largely matches  the increase in the numbers of massive passive galaxies seen over this period. We examine the size-mass relation of blue-cloud galaxies,  finding that its high-mass boundary runs along lines of constant ℳ /re or equivalently inferred velocity dispersion. Larger galaxies can continue to form stars to higher stellar masses than smaller galaxies. As  blue-cloud galaxies approach this high-mass limit, entering a narrow diagonal region within the size-mass plane termed the “quenching zone”, they start to be quenched, their d4000 values increasing to push them towards the green valley. In parallel, their structures change, showing higher Sérsic indices and central stellar mass densities. For these galaxies, bulge growth is required for them to reach the high-mass limit of the blue cloud and be quenched by internal mechanisms. The blue-cloud galaxies that are being quenched at z ~ 0.8 lie along the same size-mass relation as present day quiescent galaxies and seem the likely progenitors of today’s S0s.Publisher PDFPeer reviewe

Meta-analysis of genome-wide association studies from the CHARGE consortium identifies common variants associated with carotid intima media thickness and plaque

Carotid intima media thickness (cIMT) and plaque determined by ultrasonography are established measures of subclinical atherosclerosis that each predicts future cardiovascular disease events. We conducted a meta-analysis of genome-wide association data in 31,211 participants of European ancestry from nine large studies in the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. We then sought additional evidence to support our findings among 11,273 individuals using data from seven additional studies. In the combined meta-analysis, we identified three genomic regions associated with common carotid intima media thickness and two different regions associated with the presence of carotid plaque (P < 5 × 10 -8). The associated SNPs mapped in or near genes related to cellular signaling, lipid metabolism and blood pressure homeostasis, and two of the regions were associated with coronary artery disease (P < 0.006) in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) consortium. Our findings may provide new insight into pathways leading to subclinical atherosclerosis and subsequent cardiovascular events