Allocation Regimes Research Articles

Carbon Subsidies and Optimal Forest Management

We consider the effect of carbon credit payment schemes on forest owners' land use and harvest decisions. We study two possible credit allocation regimes: one where credits are allocated according to the actual amount of carbon sequestered by the trees on a piece of land, and another where credits are allocated according to the long-run potential to sequester carbon on the land. Using a real options model with uncertain future timber prices, we examine the effect on the timing of harvests and the replanting-abandonment decision. We show that both schemes discourage deforestation. Compensating growers for actual carbon sequestration leads to longer rotation periods between harvests, while basing compensation only on the long-run potential level of sequestration induces shorter rotation periods. The former scheme leads to greater benefits of carbon sequestration at lower cost than the latter scheme. Although inducing moderate levels of sequestration is expensive under both schemes, the cost falls dramatically when the level of payments climbs above some threshold. Indeed, providing the payments are sufficiently generous, carbon credit payment schemes offer an effective means of increasing carbon sequestration.

Optimal allocation of building blocks between nutrient uptake systems in a microbe.

A bacterial cell must distribute its molecular building blocks among various types of nutrient uptake systems. If the microbe is to maximize its average growth rate, this allocation of building blocks must be adjusted to the environmental availabilities of the various nutrients. The adjustments can be found from growth balancing considerations. We give a full proof of optimality and uniqueness of the optimal allocation regime for a simple model of microbial growth and internal stores kinetics. This proof suggests likely candidates for optimal control regimes in the case of a more realistic model. These candidate regimes differ with respect to the information that the cell's control system must have access to. We pay particular attention to one of the three candidates, a feedback regime based on a cellular control system that monitors only internal reserve densities. We show that allocation converges rapidly to balanced growth under this control regime.

The Economic Impact of Alternative Service Department Allocation Bases in Decentralised Settings

Prior work has focused on the impact of using alternative bases for allocating costs to products but there has been little work that evaluates the use of alternative allocation bases for allocating costs to departments. In particular, if different departments of a multi‐national firm are located in settings with different reporting requirements, exchange rate risks, and costs of capital, then the choice of cost allocation base can be important. This paper examines the economic impact of alternative service department allocation bases in a decentralised setting. A non‐linear programming (NLP) approach is used to model the problem. A review of prior literature identifies a method, based on the NLP approach, for determining the economic impact of alternative allocation bases in a multi‐product setting. The method is adapted in this paper for the multi‐divisional context. The study finds that centralised production volume decision‐making is superior to decentralised decision‐making using either revenue or volume‐based cost allocation bases. Under certain conditions, revenue‐based allocation bases are also found to be superior to volume bases. Under the assumptions of the model no distinction can be made between the centralised solution and a profit‐based allocation regime. A practical implication of this study is that designers of cost allocation systems need to consider not only the direct income‐shifting effect of different cost allocation bases but also the indirect economic effect of consequential changes in the operating decisions of the firm.

The British and American Rules: an Experimental Examination of Pre‐trial Bargaining in the Shadowof the Law

A commonly held view is that the frequency and value of pre‐trial settlements in civil disputes are greatly influenced by the cost allocation regime that is in place if the case goes to trial. There is a large and growing theoretical literature on this subject but almost no empirical evidence. This is due simply to the scarcity of relevant data owing to the confidentiality generally associated with such matters. However, the area is an ideal one to analyse experimentally. In this paper we consider the effect of the British and American rules for cost allocation using such an experimental methodology. We find that the two rules produce no difference in the frequency of pre‐trial settlements but that the British rule produces higher settlements (pro‐pursuer) if the probability of the pursuer winning is large.

Optimal allocation between nutrient uptake and growth in a microbial trichome

A microbial trichome grows by assimilating nutrients from its environment, and converting these into catalytic macro-molecular machinery. This machinery may be divided into assimilatory machinery and proliferative machinery. The former type is involved in nutrient uptake, whereas the latter type enables the trichome to grow. The cells in the trichome are faced with an allocation problem: given the availability of nutrients in the environment, how many macro-molecular building blocks should be allocated to the synthesis of assimilatory machinery, and how many to the synthesis of proliferative machinery? We answer this question for a particular model, which is a generalization of the Droop quota model. We formulate a two-dimensional non-linear optimal control problem, corresponding to this model. An optimal allocation regime with a singular segment is derived, based on Pontryagin’s maximum principle. We give a direct proof of optimality. We discuss how actual biological cells might implement this optimal regime.

Video Microscopical Measures of Gastrovascular Flow in Colonial Hydroids

Measures of internal fluid flow have the potential to illuminate energy allocation and life-history variation in colonial invertebrates. Using video microscopy and digital image analysis, fluid flow was characterized in hydractiniid hydroids at three regions of the dead end stolons located at the periphery of colonies. Outflow begins at an initially high rate (range 50-800 jLm/s). As the stolon fills, the outflow slows and then stops, and a period of backflow (<100 s), having a relatively low initial rate, follows. Backflow rate increases (less than or equal to outflow rate) as the stolon contracts. The cycle ends with the stolon lumen fully closed and the flow rate again equal to zero. A proximal-distal flow rate gradient is apparent over the 3 regions examined along peripheral stolons. Comparisons of peripheral stolons over several contraction cycles show that Hydractinia symbiolongicarpus has shorter and wider stolons, wider lumen diameters, shorter flow-cycle periods, and similar flow rates relative to Podocoryne carnea. In H. symbiolongicarpus, a large portion of the variation in stolon length correlates with the examined flow parameters. Surprisingly, this is not the case in P. carnea. Further, the generally larger lumen diameters of H. symbiolongicarpus are not associated with higher flow rates as would be expected if pressure and tissue resistance is similar between the species. This suggests that these hydroids may regulate fluid flow at different magnitudes, or in accordance with their distinct physiological optimums, or both. Additional key words: clonal, Cnidaria, Hydrozoa, Hydractinia, Podocoryne, image analysis Great insight into invertebrate biology has been gained by visualizing and measuring fluid flow at low Reynolds (Re) numbers (e.g., Rubenstein & Koehl 1977; Koehl & Strickler 1981; LaBarbera 1984; Loudon et al. 1994). Such analyses have helped to elucidate methods of food capture, movement, and other environmental interactions in animals that function at low Re. Curiously, despite the possibility of similar insight, fluid movements within organisms have been largely ignored. Particularly in colonial animals, in vivo analysis of fluid flow within a colony may help to illuminate how the colony allocates energy and regulates development and life history, and the extent to which physical factors govern these functions. For instance, a colony with vigorous flow to peripheral areas suggests an energy allocation regime and a complement of life-history traits different from that of a colony with sluggish flow to peripheral areas and vigorous flow in central areas (e.g., runner vs. sheet, see Buss & Blackstone 1991). Recently, video microscopy has made possible studies ranging from the cellular level (Tanner & McAteer a Author with whom to correspond. 1991; Karnaky et al. 1992; Bohrmann & Biber 1994) to the organismal level (Boraas et al. 1992; Wetherbee & Andersen 1992; Hoppin et al. 1994). Nevertheless, relatively few of such studies focus on organismal physiology in vivo (but see Colmorgen & Paul 1995; Hudetz et al. 1995). It is largely the technical challenges of these studies that have prevented their application. Our technique combines aspects of video microscopy and digital image analysis (see Rohlf & Bookstein 1990) in measures of internal fluid flow, with particular relevance to the physiology of colonial organisms, e.g., hydroids, bryozoans, kamptozoans (entoprocts), ascidians, and pterobranchs. This work provides another aspect of the general optophysiology of Paul (see Colmorgen & Paul 1995). We present experimental results obtained by this method from two species of colonial hydroids.

Opportunities for Regional and International Cooperation in the Nile Basin

ABSTRACT Prospects for the Upper Nile basin states of Egypt, Sudan, and Ethiopia point to increasing competition for Nile water resources as population and development pressures intensify for all involved. In this paper we argue that it is in no one's best interest to maintain the lack of coordination in river basin development that persists in the Nile valley Decisions made today about investments in water development projects, new irrigation schemes, and industrial projects will have consequences far into the future when water resources are in much greater demand. Furthermore, the unanticipated environmental and climatic changes of the 1980s have accelerated the need to make economic, political, and legal adjustments in the existing Nile management and allocation regime. All countries in the basin stand to gain from cooperation in the development and management of Nile water resources. Water allocation need not be a zero sum game for the riparian countries; cooperative water development efforts can lead...