“Who asked for this?”: authenticity and race-centered corporate social responsibility

The purpose of this study is to conceptualize and operationalize race-centered CSR, a combination of corporate social responsibility and corporate social advocacy concerned with repairing racial relationships and inequities, and test perceptions of authenticity of race-centered CSA. Authenticity in CSR and CSA has assumed a universal consumer, however authenticity, as a cultural construct, suggests that social identity can motivate how groups of people come to understand it. As corporate social responsibility efforts increasingly center race, race itself becomes a new measure by which to understand how those efforts are seen as authentic. The study surveyed 586 Blacks and non-Blacks using a modified version of Alhouti, Johonson, and Holloway’s (2016) consumer perceptions of CSR authenticity scale, Sellers et al.’s (1997) Multidimensional Inventory of Black Identity (MIBI) scale, and adapted measures using the concepts of reconciliation and cultural commodification to conceptualize race-centered CSR and perceptions of authenticity of race-centered CSR. Two new scales were developed to measure perceptions of commodification and reconciliatory discourse as antecedents for race-centered CSR activities. Findings of this study suggests that there are universal understandings of authenticity in race-centered and of what commodification of Black culture is in the context of race-centered CSR. More importantly, the recognition of commodification of Black culture is related to perceptions of authenticity of race-centered CSR. In addition, there are subtle differences in demographic drivers for Blacks and non-blacks, particularly political ideology (conservative Blacks vs. liberal whites) and education, age, and marital status of Black respondents in perceptions of authenticity of race-centered CSR. This study contributes to The study contributes to the body of literature on critical approaches to corporate social responsibility

Velocity renormalization and Dirac cone multiplication in graphene superlattices with various barrier edge geometries

The electronic properties of one-dimensional graphene superlattices strongly depend on the atomic size and orientation of the 1D external periodic potential. Using a tight-binding approach, we show that the armchair and zigzag directions in these superlattices have a different impact on the renormalization of the anisotropic velocity of the charge carriers. For symmetric potential barriers, the velocity perpendicular to the barrier is modified for the armchair direction while remaining unchanged in the zigzag case. For asymmetric barriers, the initial symmetry between the forward and backward momentum with respect to the Dirac cone symmetry is broken for the velocity perpendicular (armchair case) or parallel (zigzag case) to the barriers. At last, Dirac cone multiplication at the charge neutrality point occurs only for the zigzag geometry. In contrast, band gaps appear in the electronic structure of the graphene superlattice with barrier in the armchair direction.Comment: 13 pages, 14 figure

Effects of hole self-trapping by polarons on transport and negative bias illumination stress in amorphous-IGZO

The effects of hole injection in amorphous-IGZO is analyzed by means of first-principles calculations. The injection of holes in the valence band tail states leads to their capture as a polaron, with high self-trapping energies (from 0.44 to 1.15 eV). Once formed, they mediate the formation of peroxides and remain localized close to the hole injection source due to the presence of a large diffusion energy barrier (of at least 0.6eV). Their diffusion mechanism can be mediated by the presence of hydrogen. The capture of these holes is correlated with the low off-current observed for a-IGZO transistors, as well as, with the difficulty to obtain a p-type conductivity. The results further support the formation of peroxides as being the root cause of Negative bias illumination stress (NBIS). The strong self-trapping substantially reduces the injection of holes from the contact and limits the creation of peroxides from a direct hole injection. In presence of light, the concentration of holes substantially rises and mediates the creation of peroxides, responsible for NBIS.Comment: 8 pages, 8 figures, to be published in Journal of Applied Physic

Development and Validation of a new formulation of Hybrid Temporal Large Eddy Simulation

International audienceHybrid RANS-LES approaches have aroused interest for years since they provide unsteady information at a reduced numerical cost compared to LES. In the hybrid context, the use of temporal filtering, to control the energy partition between resolved and modeled scales, ensures a consistent bridging between RANS and LES models. In this regard, a new formulation of Hybrid Temporal Large Eddy Simulation (HTLES) is developed, aiming at improving the theoretical foundation of the model associated with an eddy-viscosity closure. The analytical development is performed, applying the Hybrid-Equivalence criterion, and the model is calibrated in decaying isotropic turbulence. In addition, an upgraded version of the approach is proposed to improve the behavior of the model in near-wall regions, introducing a two-fold shielding function and an internal consistency constraint to provide a suitable control of the RANS-to-LES transition. Applying HTLES to the k-w-SST model, the validation process is carried out on channel and periodic-hill flows, over a range of grids and Reynolds numbers. The predictive accuracy and the robustness to grid coarsening are assessed in these cases, ensuring that HTLES offers a cost-saving alternative to LES

Anisotropic linear forcing for synthetic turbulence generation in large eddy simulation and hybrid RANS/LES modeling

International audienceA general forcing method for Large Eddy Simulation (LES) is proposed for the purpose of providing the flow with fluctuations that satisfy a desired statistical state. This method, the Anisotropic Linear Forcing (ALF) introduces an unsteady linear tensor function of the resolved velocity which acts as a restoring force in the mean velocity and resolved stress budgets. The ALF generalizes and extends several forcing previously proposed in the literature. In order to make it possible to impose the integral length scale of the turbulence generated by the forcing term, an alternative formulation of the ALF, using a differential spatial filter, is proposed and analyzed. The anisotropic forcing of the Reynolds stresses is particularly attractive, since unsteady turbulent fluctuations can be locally enhanced or damped, depending on the target stresses. As such, it is shown that the ALF is an effective method to promote turbulent fluctuations downstream of the LES inlet or at the interface between RANS and LES in zonal hybrid RANS/LES modeling. The detailed analysis of the influence of the ALF parameters in spatially developing channel flows and hybrid computations where the ALF target statistics are given by a RANS second-moment closure show that this original approach performs as well as the synthetic eddy method. However, since the ALF method is more flexible and significant computational savings are obtained, the method appears a promising all-in-one solution for general embedded LES simulations

Encapsulation of Protonated Diamines in a Water-Soluble Chiral, Supramolecular Assembly Allows for Measurement of Hydrogen-Bond Breaking Followed by Nitrogen Inversion/Rotation (NIR)

Amine nitrogen inversion, difficult to observe in aqueous solution, is followed in a chiral, supramolecular host molecule with purely-rotational T-symmetry that reduces the local symmetry of encapsulated monoprotonated diamines and enables the observation and quantification of {Delta}G{double_dagger} for the combined hydrogen-bond breaking and nitrogen inversion rotation (NIR) process. Free energies of activation for the combined hydrogen-bond breaking and NIR process inside of the chiral assembly were determined by the NMR coalescence method. Activation parameters for ejection of the protonated amines from the assembly confirm that the NIR process responsible for the coalescence behavior occurs inside of the assembly rather than by a guest ejection/NIR/re-encapsulation mechanism. For one of the diamines, N,N,N{prime},N{prime}-tetramethylethylenediamine (TMEDA), the relative energy barriers for the hydrogen-bond breaking and NIR process were calculated at the G3(MP2)//B3LYP/6-31++G(d,p) level of theory, and these agreed well with the experimental data

Degradation of lignin β-aryl ether units in Arabidopsis thaliana expressing LigD, LigF and LigG from Sphingomonas paucimobilis SYK-6

Lignin is a major polymer in the secondary plant cell wall and composed of hydrophobic interlinked hydroxyphenylpropanoid units. The presence of lignin hampers conversion of plant biomass into biofuels; plants with modified lignin are therefore being investigated for increased digestibility. The bacterium Sphingomonas paucimobilis produces lignin-degrading enzymes including LigD, LigF and LigG involved in cleaving the most abundant lignin interunit linkage, the beta-aryl ether bond. In this study, we expressed the LigD, LigF and LigG (LigDFG) genes in Arabidopsis thaliana to introduce postlignification modifications into the lignin structure. The three enzymes were targeted to the secretory pathway. Phenolic metabolite profiling and 2D HSQC NMR of the transgenic lines showed an increase in oxidized guaiacyl and syringyl units without concomitant increase in oxidized beta-aryl ether units, showing lignin bond cleavage. Saccharification yield increased significantly in transgenic lines expressing LigDFG, showing the applicability of our approach. Additional new information on substrate specificity of the LigDFG enzymes is also provided

High Relaxivity Gadolinium Hydroxypyridonate-Viral Capsid Conjugates: Nano-sized MRI Contrast Agents

High relaxivity macromolecular contrast agents based on the conjugation of gadolinium chelates to the interior and exterior surfaces of MS2 viral capsids are assessed. The proton nuclear magnetic relaxation dispersion (NMRD) profiles of the conjugates show up to a five-fold increase in relaxivity, leading to a peak relaxivity (per Gd{sup 3+} ion) of 41.6 mM{sup -1}s{sup -1} at 30 MHz for the internally modified capsids. Modification of the exterior was achieved through conjugation to flexible lysines, while internal modification was accomplished by conjugation to relatively rigid tyrosines. Higher relaxivities were obtained for the internally modified capsids, showing that (1) there is facile diffusion of water to the interior of capsids and (2) the rigidity of the linker attaching the complex to the macromolecule is important for obtaining high relaxivity enhancements. The viral capsid conjugated gadolinium hydroxypyridonate complexes appear to possess two inner-sphere water molecules (q = 2) and the NMRD fittings highlight the differences in the local motion for the internal ({tau}{sub RI} = 440 ps) and external ({tau}{sub RI} = 310 ps) conjugates. These results indicate that there are significant advantages of using the internal surface of the capsids for contrast agent attachment, leaving the exterior surface available for the installation of tissue targeting groups