947 research outputs found

    One-loop conformal anomaly in an implicit momentum space regularization framework

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    In this paper we consider matter fields in a gravitational background in order to compute the breaking of the conformal current at one-loop order. Standard perturbative calculations of conformal symmetry breaking expressed by the non-zero trace of the energy-momentum tensor have shown that some violating terms are regularization dependent, which may suggest the existence of spurious breaking terms in the anomaly. Therefore, we perform the calculation in a momentum space regularization framework in which regularization dependent terms are judiciously parametrized. We compare our results with those obtained in the literature and conclude that there is an unavoidable arbitrariness in the anomalous term â–¡R\Box R.Comment: in European Physical Journal C, 201

    The role of the sustainability report in capitalistic firm

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    The aim and the central topic of this research is the understanding of the importance of Sustainable growth strategy approach as a driver to achieving top-line growth and bottom-line results. The main contributions of this line of research are to demonstrate the idea that the sustainability report is an instrument for social interaction and social cost/benefit analysis and to show that such an instrument can describe, comment on and sum up the firm\u2019s own behaviour aimed at sustainable growth. The work integrates the CSR management literature with a large body of research in accounting and finance. This study draws from theoretical research about the nature of the corporation, its role in society and contributions by recent research on corporate social, environmental, ethical responsibility and accountability. Our research demonstrates that the economic existence of the capitalistic firm as a producer of economic and financial values must be appreciated, in terms of the sustainability of the development path of the firm, and evaluated by a wide range of social performance measures of outcome or benefit. It also shows how the Sustainability report emphasizes the link between firm and territory, and affirms the concept of the firm as an entity that, by pursuing its own prevailing interests, contributes to improving the quality of life of the members of the society in which it operates. This paper contributes primarily to the academic debate by reviewing past attempts to theorise CSR and stakeholder dialogue, identifying gaps and weaknesses, and proposing the Sustainable Growth implementation processes for the creation of value. It also highlights the relationship between CSR activity and corporate image and performance. The research shed light on aspects of CSR activity for which little is known and much less is being understood; namely, the channels and the mechanisms through which the CSR impact is perceived and realized for creation of value. Carlotta Meo Colombo (3) considers the capitalistic firm as Business Value-Creating Organizations and Patrizia Gazzola (1-2;4-6) considers the Sustainable Growth implementation processes for the creation of value

    Conductivity of Coulomb interacting massless Dirac particles in graphene: Regularization-dependent parameters and symmetry constraints

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    We compute the Coulomb correction C\mathcal{C} to the a. c. conductivity of interacting massless Dirac particles in graphene in the collisionless limit using the polarization tensor approach in a regularization independent framework. Arbitrary parameters stemming from differences between logarithmically divergent integrals are fixed on physical grounds exploiting only spatial O(2)O(2) rotational invariance of the model which amounts to transversality of the polarization tensor. Consequently C\mathcal{C} is unequivocally determined to be (19−6π)/12(19- 6\pi)/12 within this effective model. We compare our result with explicit regularizations and discuss the origin of others results for C\mathcal{C} found in the literature

    Design and modeling of a periodic single-phase sandwich panel for acoustic insulation applications

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    Sandwich and composite panels are widely adopted in acoustic applications due to their sound insulation properties that overcome mass-law-based partitions in medium–high frequency regions. A key aspect in the design procedure of acoustic panels is the control of the resonance-dominated region of the sound transmission loss (STL) curve. Within that frequency range, such systems usually show acoustic weakness and poor insulation performances with respect to standard single-layer solutions. In the present contribution, we want to highlight an innovative approach to the sandwich partition concept. A novel single-phase sandwich panel is realized by adopting a periodic repetition of a properly designed unit cell. The resulting internal truss structure is self-sustained, and its mechanical stiffness can be tuned to maximize the STL in the resonance-dominated region. A set of parametric analyses is reported to show how the topology of the unit cell affects the noise reduction properties of the panel. Experimental validation is performed on a nylon 3D-printed prototype. The proposed panel is then integrated with some locally resonant elements that can be adopted to further improve the low-frequency STL of the solution. Industrial and production considerations are also taken into account during the design process to make the solution industrially valid with a circular economy focus

    Pathways of L-glutamic acid transport in cultured human fibroblasts.

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    The transport of L-glutamic acid has been studied in skin-derived diploid human fibroblasts. Competition analysis in the presence and absence of Na+ and mathematical discrimination by nonlinear regression indicated that L-glutamic acid enters the cell by at least three transport systems: 1) a high affinity Na+-dependent system which has been found to be identical to the previously described system for anionic amino acids (Gazzola, G. C., Dall'Asta, V., Bussolati, O., Makowske, M., and Christensen, H. N. (1981) J. Biol. Chem. 256, 6054-6059) and which is provisionally designated as System X-AG; this route was shared by L-aspartic acid; 2) a low affinity Na+-dependent system resembling the ASC System for neutral amino acids (Franchi-Gazzola, R., Gazzola, G. C., Dall'Asta, V., and Guidotti, G. G. (1982) J. Biol. Chem. 257, 9582-9587); its reactivity toward L-glutamic acid was strongly inhibited by L-serine, but not by 2-(methyl-amino)isobutyric acid; and 3) a Na+-independent system similar to System XC- described in fetal human lung fibroblasts (Bannai, S., and Kitamura, E. (1980) J. Biol. Chem. 255, 2372-2376). The XC- system served for L-glutamic acid and L-cystine, the latter amino acid behaving as a potent inhibitor of L-glutamic acid uptake. Amino acid starvation did not change the uptake of L-glutamic acid by the two Na+-dependent systems, but enhanced the activity of System XC- by increasing its Vmax. L-Glutamic acid transport was also affected by the density of the culture. An increased cell density lowered the uptake of the amino acid by Systems ASC and XC- and promoted the uptake by System X-AG. All these variations were dependent upon changes in Vmax

    Brazil nut almonds: nutritional and market aspects.

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    The aim of this study was to estimate the annual growth rate in production and exportation of Brazil nut almonds. Presents information related to the composition of different fatty acids from brazil nut almonds and the human daily intake needs, as well as an analysis of its production, its growth rate during the last 20 years and its export. and the human daily intake needs

    Sharing Positive Affective States Amongst Rodents

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    Group living is thought to benefit from the ability to empathize with others. Much attention has been paid to empathy for the pain of others as an inhibitor of aggression. Empathizing with the positive affect of others has received less attention although it could promote helping by making it vicariously rewarding. Here, we review this latter, nascent literature to show that three components of the ability to empathize with positive emotions are already present in rodents, namely, the ability to perceive, share, and prefer actions that promote positive emotional states of conspecifics. While it has often been argued that empathy evolved as a motivation to care for others, we argue that these tendencies may have selfish benefits that could have stabilized their evolution: approaching others in a positive state can provide information about the source of valuable resources; becoming calmer and optimistic around animals in a calm or positive mood can help adapt to the socially sensed safety level in the environment; and preferring actions also benefiting others can optimize foraging, reduce aggression, and trigger reciprocity. Together, these findings illustrate an emerging field shedding light on the emotional world of rodents and on the biology and evolution of our ability to cooperate in groups.</p
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