Effective medical surplus recovery

We analyze not-for-profit Medical Surplus Recovery Organizations (MSROs) that manage the recovery of surplus (unused or donated) medical products to fulfill the needs of underserved healthcare facilities in the developing world. Our work is inspired by an award-winning North American non-governmental organization (NGO) that matches the uncertain supply of medical surplus with the receiving parties’ needs. In particular, this NGO adopts a recipient-driven resource allocation model, which grants recipients access to an inventory database, and each recipient selects products of limited availability to fill a container based on its preferences. We first develop a game theoretic model to investigate the effectiveness of this approach. This analysis suggests that the recipient-driven model may induce competition among recipients and lead to a loss in value provision through premature orders. Further, contrary to the common wisdom from traditional supply chains, full inventory visibility in our setting may accelerate premature orders and lead to loss of effectiveness. Accordingly, we identify operational mechanisms to help MSROs deal with this problem. These are: (i) appropriately selecting container capacities while limiting the inventory availability visible to recipients and increasing the acquisition volumes of supplies, (ii) eliminating recipient competition through exclusive single-recipient access to MSRO inventory, and (iii) focusing on learning recipient needs as opposed to providing them with supply information, and switching to a provider-driven resource allocation model. We use real data from the NGO by which the study was inspired and show that the proposed improvements can substantially increase the value provided to recipients

The current situation of EU’s food chain

The sharp fluctuations in agricultural commodity and food prices at a time of great uncertainty about the economic outlook illustrate the need to improve the functioning of the European food supply chain with a view to enhancing its efficiency and competitiveness. Better regulation and ensuring a vigorous and coherent enforcement of competition and consumer protection rules will contribute to limiting price increases for the benefit of European consumers, in particular lower income households. Moreover, it will also help overcome the present fragmentation of the food supply chain and remove artificial entry barriers for producers, which will help European consumers benefit from the widest possible choice of quality food products. Additionally, this could help rebalancing the bargaining power in the food supply chain. Global demand and supply developments have been one of the main determinants of the rapid increase in food prices observed. Nevertheless, problems in the functioning of the food supply chain, either in terms of the degree of competition or concerning regulation may have played an important role as well. In the present economic conditions, it is therefore particularly important to analyse how to improve the functioning of the food supply chain and, in particular, to better understand the transmission mechanisms linking commodity prices with producer and consumer prices. This would help identify appropriate measures in support of the consumer's purchasing power and the competitiveness of the sectors involved. The food supply chain connects three economically important sectors: the agricultural sector, the food processing industry and the distribution sectors. These sectors account for 6% of EU value added and 12% of EU employment. As the food processing industry and the distribution sectors have many interactions with other sectors, market malfunctioning along the food supply chain can have significant repercussions. The slow productivity growth in these sectors in comparison with the US indicates that there is room for efficiency improvements.food chain, demand and supply, retirements, consumer, foodstuff’s price, Agricultural and Food Policy,

Buffering volatility : storage investments and technology-specific renewable energy support

Mitigating climate change will require integrating large amounts of highly intermittent renewable energy (RE) sources in future electricity markets. Considerable uncertainties exist about the cost and availability of future large-scale storage to alleviate the potential mismatch between demand and supply. This paper examines the suitability of regulatory (public policy) mechanisms for coping with the volatility induced by intermittent RE sources, using a numerical equilibrium model of a future wholesale electricity market. We find that the optimal RE subsidies are technology-specific reflecting the heterogeneous value for system integration. Differentiated RE subsidies reduce the curtailment of excess production, thereby preventing costly investments in energy storage. Using a simple cost-benefit framework, we show that a smart design of RE support policies significantly reduces the level of optimal storage. We further find that the marginal benefits of storage rapidly decrease for short-term (intra-day) storage and are small for long-term (seasonal) storage independent of the storage level. This suggests that storage is not likely to be the limiting factor for decarbonizing the electricity sector

Bioenergetic mechanisms of seizure control

Epilepsy is characterized by the regular occurrence of seizures, which follow a stereotypical sequence of alterations in the electroencephalogram. Seizures are typically a self limiting phenomenon, concluding finally in the cessation of hypersynchronous activity and followed by a state of decreased neuronal excitability which might underlie the cognitive and psychological symptoms the patients experience in the wake of seizures. Many efforts have been devoted to understand how seizures spontaneously stop in hope to exploit this knowledge in anticonvulsant or neuroprotective therapies. Besides the alterations in ion-channels, transmitters and neuromodulators, the successive build up of disturbances in energy metabolism have been suggested as a mechanism for seizure termination. Energy metabolism and substrate supply of the brain are tightly regulated by different mechanisms called neurometabolic and neurovascular coupling. Here we summarize the current knowledge whether these mechanisms are sufficient to cover the energy demand of hypersynchronous activity and whether a mismatch between energy need and supply could contribute to seizure control

Water Markets in China: Challenges, Opportunities, and Constraints in the Development of Market-Based Mechanisms for Water Resource Allocation in the People's Republic of China

This discussion paper examines the development of water markets as a solution to water scarcity in China, with particular focus on Water Rights Trading (WRT). Water scarcity is an issue of growing concern for China, particularly in the north, where a combination of limited water sup- plies, economic growth, and population increases are increasingly straining water resources. The Chinese government has moved enthusiastically toward an embrace of market mechanisms to address water scarcity, with WRT being the preferred policy instrument in the agricultural sector, which accounts for the majority of water use in China. Proposed advantages of WRT include a more efficient allocation of scarce water resources and the ability to limit total water use in a given region by carefully limiting rights allocation. However, the implementation of WRT has encountered significant challenges in China, which include a lack of effective monitoring and enforcement of water use, conflicts of interest between various units of government, which prevent effective administration, and a lack of integration with other approaches to water scarcity, including supply augmentation. In light of these challenges, this analysis concludes that market-based mechanisms in general, and WRT in particular, have an important but only partial role to play in alleviating water scarcity in China. This discussion paper proposes several policy recommendations to improve the development of water markets in China, in particular by lowering the transaction costs to establishing markets and improving policy coordination

Lumpy species coexistence arises robustly in fluctuating resource environments

The effect of life-history traits on resource competition outcomes is well understood in the context of a constant resource supply. However, almost all natural systems are subject to fluctuations of resources driven by cyclical processes such as seasonality and tidal hydrology. To understand community composition, it is therefore imperative to study the impact of resource fluctuations on interspecies competition. We adapted a well-established resource-competition model to show that fluctuations in inflow concentrations of two limiting resources lead to the survival of species in clumps along the trait axis, consistent with observations of “lumpy coexistence” [Scheffer M, van Nes EH (2006) Proc Natl Acad Sci USA 103:6230–6235]. A complex dynamic pattern in the available ambient resources arose very early in the self-organization process and dictated the locations of clumps along the trait axis by creating niches that promoted the growth of species with specific traits. This dynamic pattern emerged as the combined result of fluctuations in the inflow of resources and their consumption by the most competitive species that accumulated the bulk of biomass early in assemblage organization. Clumps emerged robustly across a range of periodicities, phase differences, and amplitudes. Given the ubiquity in the real world of asynchronous fluctuations of limiting resources, our findings imply that assemblage organization in clumps should be a common feature in nature

Starve Cancer Cells of Glutamine: Break the Spell or Make a Hungry Monster?

Distinct from normal differentiated tissues, cancer cells reprogram nutrient uptake and utilization to accommodate their elevated demands for biosynthesis and energy production. A hallmark of these types of reprogramming is the increased utilization of, and dependency on glutamine, a nonessential amino acid, for cancer cell growth and survival. It is well-accepted that glutamine is a versatile biosynthetic substrate in cancer cells beyond its role as a proteinogenic amino acid. In addition, accumulating evidence suggests that glutamine metabolism is regulated by many factors, including tumor origin, oncogene/tumor suppressor status, epigenetic alternations and tumor microenvironment. However, despite the emerging understanding of why cancer cells depend on glutamine for growth and survival, the contribution of glutamine metabolism to tumor progression under physiological conditions is still under investigation, partially because the level of glutamine in the tumor environment is often found low. Since targeting glutamine acquisition and utilization has been proposed to be a new therapeutic strategy in cancer, it is central to understand how tumor cells respond and adapt to glutamine starvation for optimized therapeutic intervention. In this review, we first summarize the diverse usage of glutamine to support cancer cell growth and survival, and then focus our discussion on the influence of other nutrients on cancer cell adaptation to glutamine starvation as well as its implication in cancer therapy

An equilibrium model for ribosome competition

The number of ribosomes in a cell is considered as limiting, and gene expression is thus largely determined by their cellular concentration. In this work we develop a toy model to study the trade-off between the ribosomal supply and the demand of the translation machinery, dictated by the composition of the transcript pool. Our equilibrium framework is useful to highlight qualitative behaviours and new means of gene expression regulation determined by the fine balance of this trade-off. We also speculate on the possible impact of these mechanisms on cellular physiology