Do the buyback contracts of undistributed stocks coordinate the supply chain?

The concept of supply chain coordination implies that it is possible to obtain an optimal result for both independent chain participants and supply chain due to participants’ coordinated actions. This paper examines the question whether a buyback contract will be coordinating or not. The authors argue that a coordinating buyback contract should have the following substantive properties: practical feasibility, collective and individual rationality. The paper off ers a mathematical defi nition of a coordinating buyback contract which highlights these properties. Entering into buyback contract process is considered as a two-step game of two players (a supplier and retailer) on the assumption that the players are risk neutral and make decisions with full information available, the market price is fixed, and the product demand is a random variable. The authors demonstrate that the buyback contract does not coordinate the chain, however, there has been obtained a non-empty set of eff ective contracts depending on the buyback price. For such contracts, the defi nition of “conditional coordination” is given to introduce the property of a supplier’s partial rationality; its existence was proved. The findings reveal that the choice of buyback price affects the allocation of profits between chain participants so the decision on its choice must be cooperative. To substantiate the nature of cooperative choice of conditionally coordinating contracts, the asymmetric Nash solution is considered. All results were obtained both in general terms and under the assumption that the product demand has uniform distribution. For the latter case, the conditionally coordinating contract parameters were found and it was justified that the conclusion of such a contract is possible only when a supplier has greater bargain power than a retailer.

Approaches for extending human healthspan: from antioxidants to healthspan pharmacology

Dramatic increases in human lifespan and declining population growth are monumental achievements but these same achievements have also led to many societies today ageing at a faster rate than ever before. Extending healthy lifespan (healthspan) is a key translational challenge in this context. Disease-centric approaches to manage population ageing risk are adding years to life without adding health to these years. The growing consensus that ageing is driven by a limited number of interconnected processes suggests an alternative approach. Instead of viewing each age-dependent disease as the result of an independent chain of events, this approach recognizes that most age-dependent diseases depend on and are driven by a limited set of ageing processes. While the relative importance of each of these processes and the best intervention strategies targeting them are subjects of debate, there is increasing interest in providing preventative intervention options to healthy individuals even before overt age-dependent diseases manifest. Elevated oxidative damage is involved in the pathophysiology of most age-dependent diseases and markers of oxidative damage often increase with age in many organisms. However, correlation is not causation and, sadly, many intervention trials of supposed antioxidants have failed to extend healthspan and to prevent diseases. This does not, however, mean that reactive species (RS) and redox signalling are unimportant. Ultimately, the most effective antioxidants may not turn out to be the best geroprotective drugs, but effective geroprotective interventions might well turn out to also have excellent, if probably indirect, antioxidant efficacy.

2-[(3S,3aS,5R,8S,8aS)-3,8-Dimethylhexahydro-1H,4H-3a,8a-epoxyazulen-5-yl]propan-2-ol

Four independent molecules (A–D) comprise the asymmetric unit of the title compound, C15H26O2, which differ only in the relative orientations of the terminal –C(Me)2OH groups [e.g.the range of Cmethylene—Cmethine—Cquaternary—Ohydroxytorsion angles is 52.7 (7)–57.1 (6)°, where the Cmethyleneatom is bound to an epoxide C atom]. The five-membered rings adopt envelope conformations, with the methylene C atom adjacent to the methine C atom being the flap atom in each case. In each molecule, the conformation of the seven-membered ring is a half-chair, with the Cmethylene—Cmethinebond, flanked by methylene C atoms, being the back of the chair. Supramolecular helical chains along thebaxis are found in the crystal packing, sustained by hydroxy–epoxide O—H...O hydrogen bonding. Molecules ofAself-associate into a chain as do those ofD. A third independent chain comprisingBandCmolecules is also formed. The studied crystal is a pseudo-merohedral twin (minor componentca21%).

Further Effects of Chain-Length-Dependent Reactivities on Radical Polymerization Kinetics

In the present paper, we finalize some threads in our investigations into the effects of chain-length-dependent propagation (CLDP) on radical polymerization kinetics, confirming all our previous conclusions. Additionally, and more significantly, we uncover some unexpected and striking effects of chain-length-dependent chain transfer (CLDTr). It is found that the observed overall rate coefficients for propagation and termination (and therefore the rate of polymerization) are not significantly affected by whether or not chain transfer is chain-length dependent. However, this situation is different when considering the molecular weight distributions of the resulting polymers. In the case of chain-length-independent chain transfer, CLDP results in a considerable narrowing of the distribution at the low molecular weight side of the distribution in a chain-transfer controlled system. However, the inclusion of both CLDP and CLDTr yields identical results to classical kinetics – in these latter two cases, the molecular weight distribution is governed by the same chain-length-independent chain transfer constant, whereas in the case of CLDP only, it is governed by a chain-length-dependent chain transfer constant that decreases with decreasing chain length, thus enhancing the probability of propagation for short radicals. Furthermore, it is shown that the inclusion of a very slow first addition step has tremendous effects on the observed kinetics, increasing the primary radical concentration and thereby the overall termination rate coefficient dramatically. However, including possible penultimate unit effects does not significantly affect the overall picture and can be ignored for the time being. Lastly, we explore the prospects of using molecular weight distributions to probe the phenomena of CLDP and CLDTr. Again, some interesting insights follow.