Maximum Quota Research Articles

Assessing the sustainability of African lion trophy hunting, with recommendations for policy.

While trophy hunting provides revenue for conservation, it must be carefully managed to avoid negative population impacts, particularly for long-lived species with low natural mortality rates. Trophy hunting has had negative effects on lion populations throughout Africa, and the species serves as an important case study to consider the balance of costs and benefits, and to consider the effectiveness of alternative strategies to conserve exploited species. Age-restricted harvesting is widely recommended to mitigate negative effects of lion hunting, but this recommendation was based on a population model parameterized with data from a well-protected and growing lion population. Here, we used demographic data from lions subject to more typical conditions, including source-sink dynamics between a protected National Park and adjacent hunting areas in Zambia's Luangwa Valley, to develop a stochastic population projection model and evaluate alternative harvest scenarios. Hunting resulted in population declines over a 25-yr period for all continuous harvest strategies, with large declines for quotas >1 lion/concession (~0.5 lion/1,000km2 ) and hunting of males younger than seven years. A strategy that combined periods of recovery, an age limit of ≥7yr, and a maximum quota of ~0.5 lions shot/1,000km2 yielded a risk of extirpation <10%. Our analysis incorporated the effects of human encroachment, poaching, and prey depletion on survival, but assumed that these problems will not increase, which is unlikely. These results suggest conservative management of lion trophy hunting with a combination of regulations. To implement sustainable trophy hunting while maintaining revenue for conservation of hunting areas, our results suggest that hunting fees must increase as a consequence of diminished supply. These findings are broadly applicable to hunted lion populations throughout Africa and to inform global efforts to conserve exploited carnivore populations.

Strategyproof matching with regional minimum and maximum quotas

This paper considers matching problems with individual/regional minimum/maximum quotas. Although such quotas are relevant in many real-world settings, there is a lack of strategyproof mechanisms that take such quotas into account. We first show that without any restrictions on the regional structure, checking the existence of a feasible matching that satisfies all quotas is NP-complete. Then, assuming that regions have a hierarchical structure (i.e., a tree), we show that checking the existence of a feasible matching can be done in time linear in the number of regions. We develop two strategyproof matching mechanisms based on the Deferred Acceptance mechanism (DA), which we call Priority List based Deferred Acceptance with Regional minimum and maximum Quotas (PLDA-RQ) and Round-robin Selection Deferred Acceptance with Regional minimum and maximum Quotas (RSDA-RQ). When regional quotas are imposed, a stable matching may no longer exist since fairness and nonwastefulness, which compose stability, are incompatible. We show that both mechanisms are fair. As a result, they are inevitably wasteful. We show that the two mechanisms satisfy different versions of nonwastefulness respectively; each is weaker than the original nonwastefulness. Moreover, we compare our mechanisms with an artificial cap mechanism via simulation experiments, which illustrate that they have a clear advantage in terms of nonwastefulness and student welfare.

Strategyproof Matching with Minimum Quotas

We study matching markets in which institutions may have minimum and maximum quotas. Minimum quotas are important in many settings, such as hospital residency matching, military cadet matching, and school choice, but current mechanisms are unable to accommodate them, leading to the use of ad hoc solutions. We introduce two new classes of strategyproof mechanisms that allow for minimum quotas as an explicit input and show that our mechanisms improve welfare relative to existing approaches. Because minimum quotas cause a theoretical incompatibility between standard fairness and nonwastefulness properties, we introduce new second-best axioms and show that they are satisfied by our mechanisms. Last, we use simulations to quantify (1) the magnitude of the potential efficiency gains from our mechanisms and (2) how far the resulting assignments are from the first-best definitions of fairness and nonwastefulness. Combining both the theoretical and simulation results, we argue that our mechanisms will improve the performance of matching markets with minimum quota constraints in practice.

Assessing the maximum expendable quota for a milestone financing provided by a venture capitalist

In the expansion phase, young ventures often face a financing bottleneck. Initial company owners seek equity partners, usually in their (extended) network. In this paper, we demonstrate how the state marginal quota model under realistic imperfect market conditions can assist company founders striving for venture capital financed growth in the expansion phase. Applying this model, initial company owners can determine the maximum expendable percentage of ownership for a given milestone financing. This paper also shows that under unrealistic perfect market conditions, there is no apparent reason for venture capital to exist.

Phormidium autumnale Growth and Anatoxin-a Production under Iron and Copper Stress

Studies on planktonic cyanobacteria have shown variability in cyanotoxin production, in response to changes in growth phase and environmental factors. Few studies have investigated cyanotoxin regulation in benthic mat-forming species, despite increasing reports on poisoning events caused by ingestion of these organisms. In this study, a method was developed to investigate changes in cyanotoxin quota in liquid cultures of benthic mat-forming cyanobacteria. Iron and copper are important in cellular processes and are well known to affect growth and selected metabolite production in cyanobacteria and algae. The effect of iron (40–4000 μg L−1) and copper (2.5–250 μg L−1) on growth and anatoxin-a quota in Phormidium autumnale was investigated in batch culture. These concentrations were chosen to span those found in freshwater, as well as those previously reported to be toxic to cyanobacteria. Anatoxin-a concentrations varied throughout the growth curve, with a maximum quota of between 0.49 and 0.55 pg cell−1 measured within the first two weeks of growth. Growth rates were significantly affected by copper and iron concentrations (P < 0.0001); however, no statistically significant difference between anatoxin-a quota maxima was observed. When the iron concentrations were 800 and 4000 μg L−1, the P. autumnale cultures did not firmly attach to the substratum. At 250 μg L−1 copper or either 40 or 4000 μg L−1 iron, growth was suppressed.

Systematic Photovoltaic Waste Recycling

AbstractIndium, selenium, tellurium, gallium, molybdenum, cadmium and silicon are some of the major elements used in photovoltaic cells. Fully aware of the limited availability of these metals in future, recycling has been recognized as the most advisable end-of-life strategy to save these raw materials from turning into production wastes. On the other hand, statutory measures such as “Kreislaufwirtschaftsgesetz” (the German law encouraging closed-loop economy) aim to achieve a maximum quota of recycling and a minimum use of resources such as energy and raw materials. By the year of 2050, end-of-life photovoltaic panels are anticipated to amount to 9.57 million tons [1]. Although we are not there yet, discussions on recycling have already started. We have to prepare for higher waste volumes expected in the coming years. But already today we need to solve some environmental problems like loss of conventional resources (e.g., glass) and rare metals [2]. All of the known approaches for recycling photovoltaic semiconductor material seem economically and environmentally inefficient [3, 4]. In this paper, we report about reclaiming metals from scrap of thin film systems and associated photovoltaic manufacturing wastes like sandblasting dust and overspray. We also report one universal wet-chemical treatment for reclaiming the metals from CIS, CIGS or CdTe photovoltaic waste. Further, we discuss the application of our method to new PV systems, such as substrates other than glass (stainless steel, aluminum or plastic foil sheets) and alternative semiconductor alloys such as GaAs.

Medical schools exceed permitted overseas student quota to boost income, claims BMA

UK medical schools have been contributing to the oversubscription of foundation year 1 (F1) placements for newly qualified doctors by getting round their maximum quota of overseas students, the chairman of the BMA’s Junior Doctors Committee, Ben Molyneux, has claimed. The body that represents medical schools in the UK, the Medical Schools Council, has denied the claim. Molyneux told BMJ Careers that the permitted proportion of medical students from overseas was 7.5% of the annual intake but that most medical schools exceeded that figure to boost their income. “Overseas students are very lucrative, and most [medical schools] take more than the [permitted] maximum by changing the calculations, so inflating numbers to over 10%,” he explained. “That happens to be the amount of oversubscription we are looking at,” he said. However, he acknowledged that graduates …

Optimal phytoplankton cell size in an allometric model

The competitive ability of phytoplankton cells is simulated in a model chemostat in which cell size is considered to be an adaptive trait. Parameters describing nutrient uptake kinetics are constrained by empirically derived allometric rules. With a steady input of a single nutrient, the evolutionarily stable cell size is selected through competition among phytoplankton. We find that large cells may be favored when (1) phytoplankton growth is limited by the rate at which internally stored inorganic nutrients can be converted into biomass, and (2) maximum quotas increase with size faster than minimum quotas. Increased internal quotas then accelerate the rate of biomass production in large cells, despite their enhanced requirements for resources. The evolutionarily stable strategy is set by the allometric relationships for nutrient uptake kinetics and by metabolism.

DEREGULATION OF INDONESIA'S INTERREGIONAL AGRICULTURAL TRADE

In January 1998 a significant policy reform deregulated agriculture in Indonesia. It sought to eliminate distorting local monopolies, monopsonies, trade restrictions, interisland maximum shipment quotas and other barriers that effectively lowered farmgate prices. Many of these had been constructed to benefit the Soeharto family and their business cronies. The reform also sought to lower local taxes and levies targeted at agriculture. This paper demonstrates that deregulation eliminated many of the distorting taxes and levies, and dismantled many (but not all) local monopolies, monopsonies and quotas. Farmers typically now receive a higher percentage of the destination market price. Many also receive significantly higher real prices for their products, although this differs dramatically across commodities. Local governments complained about local revenues lost through the reforms. Detailed budget analyses reveal that deregulation did not substantially harm local government budgets; instead, other factors caused a decline in the local-source revenue contribution to local budgets.

The Institutional Regulation of Uneven Development: The Case of Poultry Production in the Province of Ontario

Recent contributions to the regulationist literature have identified the need for theoretically-informed but contextually-based analyses of the mode of social regulation (MSR). The mechanisms which link the MSR to uneven development in the economy require closer analysis. The paper addresses both issues in the context of state regulation of the agricultural sector through supply management. State regulation of the poultry industry in Ontario relies on a number of mechanisms set within a corporatist institutional system, including production quotas, maximum quota limits, cost of production formulae and a legal appeals procedure. The MSR mediates relations between industrial and financial capitals and the farm sector to the mutual advantage of both sets of ‘Stakeholders’. Consumers, and producers forced out of production, bear the cost of state regulation.

Temperature effects on steady-state growth, phosphorus uptake, and the chemical composition of a marine phytoplankter

The marine chrysophyteMonochrysis lutheri was grown in phosphorus-limited continuous cultures at temperatures of 15°, 18.8° and 23°C. The effect of temperature on the maximum growth rate was well-defined by the Arrhenius equation, but the Q10 for this alga (1.7) was somewhat lower than has been determined previously for many other phytoplankton species (2.0-2.2). The minimum phosphorus cell quota was relatively unaffected by temperature at 18.8°C and 23°C, but doubled in magnitude at 15°C. As a result, the internal nutrient equation of Droop described the relationship between specific growth rate and phosphorus cell quota well at 18.8° and 23°C, but was less successful at 15°C. The major limitation in using the Droop equation is that the ratio between the minimum and maximum cell quotas must be known, thus necessitating the need to establish the true maximum growth rate by the cell washout technique. In addition, the phosphorus uptake rate on a cell basis at a given steady state growth rate (=specific uptake rate) increased dramatically at 15°C, whereas the turnover rate of total available phosphorus was unaffected by temperature. Both the nitrogen and carbon cell quotas were relatively unaffected by growth rate at a given temperature, but the average values increased slightly with decreasing temperature. The overall conclusion is that phytoplankton growth and limiting-nutrient uptake rates are only synchronous at or near the optimum temperature. Because these types of responses are species specific, much additional data on temperature effects will be required before the importance of including such effects in phytoplankton-nutrient models can be determined.

Fishery Regulations in the ICNAF Area

Several countries have been fishing in the Northwest Atlantic Ocean for 300 years, and recently pressure on the stocks has increased greatly. The need for conservation resulted in the creation of the International Commission for the Northwest Atlantic Fisheries (ICNAF) in 1950. By 1972 16 countries were party to the Convention.When the Convention came into force, the catch in the Convention area was 1.7 million metric tons; by 1968 this had risen to 3.9 million metric tons, after which it has declined, largely because of lower cod, herring, and haddock catches.The main objective of ICNAF is to maintain the fish stocks at levels permitting maximum sustainable yields. The first regulation applied by the Commission was the fixing of minimum sizes of trawlnet meshes used to catch a number of important demersal species. At its 1972 meeting other measures were introduced, notably the fixing of maximum quotas for several subareas and for the more important species. ICNAF is therefore the international commission which has the most thorough and extensive regulation measures.At meetings in 1971 and 1972 the Commission concluded that exploitation of the major species in the ICNAF area was extremely high and that it was necessary to reduce fishing effort. These conclusions were arrived at on the basis of intensive research. Ten years of research on cod stocks is described as an example of this kind of work. It led to the conclusion that mesh size limitations were not sufficient to maintain the stocks of cod, and this was one of the strong reasons for adoption of the quotas, a step which is of great significance in international fisheries management.