Knowledge Structures.

This paper investigates how technological distance between firms affects their network of R&D alliances. Our theoretic model assumes that the benefit of an alliance between two firms is given by their technological distance. This benefit-distance relationship determines the ego-network of each firm as well as the overall network structure. Empirical relevance is confirmed for the bio-pharmaceutical industry. Although we find that the network structure is largely explained by firm size, technological distance determines the positioning of firms in the network.technological distance, research alliance, network formation, pharmaceutical industry.

On the value of foreign PhDs in the developing world: Training versus selection effects

This paper compares the career effects of overseas and domestic PhD training for scientists working in an emerging economy, South Africa. Variations in scientific achievements of South African academics may arise because those who attend \better" PhD programmes receive better training, but it may also be because good students select into good universities. We examine selection and training effects for four tiers of South African and two tiers of foreign universities. Those who received PhDs from universities in industrialized countries tend to be more productive than those whose PhDs were locally granted, but universities from industrialized countries do not necessarily provide better training than local universities. Pure selection effects contribute to career outcomes nearly as much as training effects. When looking at training in isolation, PhDs from top South African universities produce a similar quantity and quality research output to those from leading universities in the developed world

Locking-Free Mixed Finite Element Methods and Their Spurious Hourglassing Patterns

We present the five field mixed finite element formulation introduced by Armero and extend it to 3D problems. It combines the nonlinear mixed pressure element with an enhanced assumed strain (EAS) method based on the transposed Wilson modes. The well-known mixed pressure element arises from a Hu-Washizu-like variational principle, where dilatation and pressure are independent variables. This functional is further modified using the EAS framework to get the mixed formulation presented in this work. The element is compared to several mixed pressure and EAS element formulations showing its great performance in alleviating volumetric and shear locking in large deformation problems. The main focus of the present work is spurious hourglassing of mixed finite elements that arise in hyperelastic and elasto-plastic simulations

Pharmacophagy and pharmacophory: mechanisms of self-medication and disease prevention in the honeybee colony (Apis mellifera)

International audienceAbstractApitherapy promises cures for diseases in human folk medicine, but the effects of honeybee produced and foraged compounds on bee health are less known. Yet, hive products should chiefly facilitate medication and sanitation of the honeybees themselves rather than other organisms. We here review the impact of both self-produced gland secretions and foraged hive products (pharmacognosy) on colony health. Although foraged plant-derived compounds vary highly in antibiotic activity depending on the floral and regional origins, secondary plant metabolites in honey, pollen and propolis are important for the antibiotic activity against pathogens and parasites. However, specific bee health-enhancing activities of bee products should clearly be distinguished from the effects of an intact nutrition ensuring the basic immune competence of bees. Further unravelling the interactions among groups of active substances or individual compounds used in concert with specific behavioural adaptations will deepen our understanding of the natural potential of honeybees to maintain colony health

Preserving Nature

To consider the broader environmental significance of protecting species at risk of extinction, we must first consider the roles or functions that species fulfill in nature. Although nature has many definitions, here we define it to mean the end product of ecological and evolutionary processes. That is, within ahabitat, region, or biosphere, the condition of the soil, water, air, and biota reßects the outcome of physical, chemical, ecological, and evolutionary processes. We refer to this combination of abiotic and biotic conditions as nature and to the ecological and evolutionary processes that create it as natural processes. Using these definitions, we propose three approaches in which environmental actions can protect or conserve nature. The first approach is to preserve natural processes by directly managing them or providing suitable substitutions. For example, we can directly manage apolluted watershed to restore its water quality, or we can build expensive water treatment facilities to treat the water (Chichilnisky and Heal1998). The second approach is to protect nature itself, assuming that with adequate protection nature and its natural processes will persist. For example, we can designate marine protected areas that exclude human activities. The third approach is to protect the biotic components of nature that govern the environment. This approach encompasses the intent of the Endangered Species Act (ESA): to protect nature by protecting species. In this chapter, we examine the broader environmental significance of the Endangered Species Act by reviewing the roles species play in natural processes and by examining how natural processes govern our environment, how human activities modify nature, and how the Endangered Species Act can ameliorate the impacts of human activities

Preserving Nature

To consider the broader environmental significance of protecting species at risk of extinction, we must first consider the roles or functions that species fulfill in nature. Although nature has many definitions, here we define it to mean the end product of ecological and evolutionary processes. That is, within ahabitat, region, or biosphere, the condition of the soil, water, air, and biota reßects the outcome of physical, chemical, ecological, and evolutionary processes. We refer to this combination of abiotic and biotic conditions as nature and to the ecological and evolutionary processes that create it as natural processes. Using these definitions, we propose three approaches in which environmental actions can protect or conserve nature. The first approach is to preserve natural processes by directly managing them or providing suitable substitutions. For example, we can directly manage apolluted watershed to restore its water quality, or we can build expensive water treatment facilities to treat the water (Chichilnisky and Heal1998). The second approach is to protect nature itself, assuming that with adequate protection nature and its natural processes will persist. For example, we can designate marine protected areas that exclude human activities. The third approach is to protect the biotic components of nature that govern the environment. This approach encompasses the intent of the Endangered Species Act (ESA): to protect nature by protecting species. In this chapter, we examine the broader environmental significance of the Endangered Species Act by reviewing the roles species play in natural processes and by examining how natural processes govern our environment, how human activities modify nature, and how the Endangered Species Act can ameliorate the impacts of human activities

Blockchain for the circular economy: Theorizing blockchain\u27s role in the transition to a circular economy through an empirical investigation

Blockchain is increasingly lauded as an enabler of the transition to a circular economy. While there is considerable conceptual research and some empirical studies on this phenomenon, scholars have yet to develop a theoretical model of blockchain\u27s role in this transition. Grounded in the sustainability transition literature, this paper addresses this gap through the following research question: What role does blockchain play in the transition to a circular economy? Following an abductive approach, we conducted interviews with ground-level experts implementing blockchain innovations for the circular economy across Europe and the United States. Through a thematic analysis, we derived a theoretical model of the relationships among (1) drivers and barriers of the transition to a circular economy, (2) blockchain innovation for the circular economy, (3) technical challenges of blockchain, and (4) the circular economy. While blockchain plays a moderating role, interviewees considered it only an infrastructural resource rather than a panacea

Substitution lability of the perfluorinated Cp* ligand in Rh(i) complexes

Several cationic rhodium(I) complexes [Rh(COD)L2][C5(CF3)5] have been synthesized through substitution of the weakly bound [C5(CF3)5]− ligand from [Rh(COD)(C5(CF3)5)], further emphasizing its unique reactivity. Besides acetonitrile, pyridine derivatives with varying degrees of fluorination have been employed as ligands in order to investigate the influence of fluorination upon the binding affinity towards the resulting [Rh(COD)]+ fragment and the limit as to which the [C5(CF3)5]− ligand can be displaced. Furthermore, the newly synthesized compounds represent rare examples of rhodium complexes containing fluorinated pyridines as ligands