Common property resources in drylands of India

Common property resources are areas of land or water being used by a community or a group of communities. These have special significance to peoples and communities who depend on them for their livelihood. The commons in all arid districts of India include village pastures, community forests, wasteland, common threshing grounds, waste dumps, watershed drainage, village baoris¹, talabs², nadis³ and ponds, and tanks, rivers, rivulets, wetlands, riverbeds, community conserved areas, protected areas, Dhaam⁴ or Dhooni⁵, culturable wastelands, barren & un-culturable land, etc. The area under commons often ranged from 9 to 28% of total village area. Appropriation of the commons by the state for building essential infrastructure such as schools, clinics, veterinary hospitals, housing for government functionaries, SEZ and industrial corridors, etc. is a cause of serious concern. Presently the ownership rights over CPRs are not clear and there are many who claim ownership, some at State level but also like local bodies. The 12^th plan of the Planning Commission of India recognized and highlighted the need for favourable land tenure arrangements, institutional design and programme architecture in order to achieve effective governance and management of the commons. The revitalization of CPRs is crucial for protecting livelihoods, as well as for biodiversity conservation and for the improvement in arid microclimatic conditions. Dialogue continues on the status of common property resources, the available legal framework and some policy related issues for its conservation through strengthening of local institutions and capacity building for stakeholders.     

Dynamic Bayesian network modeling of reliability of subsea blowout preventer stack in presence of common cause failures

A subsea blowout preventer (BOP) stack is used to seal, control and monitor oil and gas wells. It can be regarded as a series–parallel system consisting of several subsystems. This paper develops the dynamic Bayesian network (DBN) of a parallel system with n components, taking account of common cause failures and imperfect coverage. Multiple error shock model is used to model common cause failures. Based on the proposed generic model, DBNs of the two commonly used stack types, namely the conventional BOP and modern BOP are developed. In order to evaluate the effects of the failure rates and coverage factor on the reliability and availability of the stacks, sensitivity analysis is performed.     

Can incomplete information lead to under-exploitation in the commons?

This paper analyzes the protection of a common pool resource (CPR) through the management of information. Specifically, we examine an entry deterrence model between an incumbent perfectly informed about the initial stock of a CPR and an uninformed potential entrant. In our model, the appropriation of the CPR by the incumbent reduces both players' future profits from exploiting the resource. In the case of complete information, we show that the incumbent operating in a high-stock common pool overexploits the CPR during the first period since it does not internalize the negative external effect that its first-period exploitation imposes on the entrant's future profits. This inefficiency, however, is absent when the commons totally regenerate across periods. Under incomplete information, we identify an additional form of inefficiency. In particular, the incumbent operating in a low-stock CPR underexploits the resource in order to signal the low available stock to potential entrants, deterring entry.     

Performance and emission characteristic studies on CRDI diesel engine fuelled with plastic pyrolysis oil blended with ethanol and diesel

ABSTRACT

This paper mainly focuses on the utilisation of plastic pyrolysis oil (PPO) and its’ blends with diesel and ethanol in different proportions in a modified diesel engine fitted with common rail direct injection (CRDI) facility. PPO was subsequently blended with diesel and ethanol and characterisation has been done. Experiments were conducted to investigate the impact of injection timing (IT) and injection pressure (IP) on the performance of modified CRDI engine fuelled with PPO and its blends with diesel and ethanol. From the experimental investigations, IT of 10°bTDC and IP of 900 bar were found as best operating parameters to obtain maximum brake thermal efficiency (BTE) with lowered emissions for the fuel combinations utilised in the investigations. PPO as substitute to diesel fuel could be viable if its major concern is to finding permanent resources.     

On the choice of farm management practices after the reform of the Common Agricultural Policy in 2003

The Common Agricultural Policy (CAP) was fundamentally reformed in 2003. From 2005, farmers will receive decoupled income support payments instead of production premiums if basic standards for environment, food safety, animal health and welfare are met. Farmers are likely to adjust production and management practices to the new policy framework. We describe how this reform fits into the EU strategy of making agricultural production more environmentally friendly by concentrating on the financial aspects of the reforms. Using an agricultural sector model for Austria, we show that the reform will further decrease agricultural outputs, reduce farm inputs, lessen nitrogen surpluses and make environmentally friendly management practices more attractive for farmers.     

Predators choosing between patches with standing crop: the influence of switching rules and input types

Where prey arriving in a patch are not consumed immediately, they will accumulate. Predators are then presented with a prey density or standing crop that increases through further input, and decreases through the consumption by predators. Firstly, I show that the switching rule of predators has a significant influence on the expected predator equilibrium distribution in such a dynamic system. Three rules are compared; for all rules, analytical solutions are calculated (where possible). To test their plausibility for natural situations, predator distributions are simulated given the assumption that each predator obtains individual patch profitability estimates by using a common learning rule. As long as prey arrive in the patches in constant numbers per time unit, the first rule leads to input matching because predators stop switching when consumption in the two patches is equal. The other two rules, where predators continue to sample both patches even in the equilibrium state, lead to predator distributions where the more profitable patch is underused. The final equilibrium depends on the exact assumptions of the switching rule; however, it is independent of interference. But if the input delivered into a patch is a function of the current prey standing crop (for example in a reproducing prey population), predator and prey distributions will not reach an equilibrium in most cases: either standing crops increase indefinitely, or they approach zero, with all predators concentrating on the better patch. Only a small number of parameter sets show intermediate crops that are reasonably stable. With this input type, only up to 54% of the simulations reach the expected distribution. In a system with competition for dynamic standing crop, it is therefore essential to know the type of input and the switching-rule used by predators to be able to predict equilibrium predator distributions. Received: 17 March 1995/Accepted after revision: 5 November 1995     

Ideal free distributions under predation risk

 We examine the trade-off between gathering food and avoiding predation in the context of patch use by a group of animals. Often a forager will have to choose between feeding sites that differ in both energetic gain rate and predation risk. The ideal site will have a high gain rate and low risk of predation. However, intake rate will often decrease when the patch is shared with other foragers and it may be optimal for some individuals to feed elsewhere. Within the framework of ideal free theory, we investigate the distribution of foragers that will equalise individual fitness gains. We focus on a two-patch environment with continuous inputs of food. With reference to existing experimental studies, we examine the effects of risk dilution, food input rates and an animal’s expectations of the future. We identify the effect of total animal numbers when one patch is subject to predation risk and the other is safe. Conditions under which the difference in intake rate in the two patches is constant are identified, as are conditions in which the ratio of animals in the two patches is constant. If current conditions do not alter future expectations an increase in input rates to the patches promotes increased use of the risky patch. Yet, if conditions are assumed to persist indefinitely the opposite effect is seen. When both patches are subject to predation risk, dilution of risk favours more extreme distributions, and may lead to more than one stable distribution. The results of these models are used to critically analyse previous work on the energetic equivalence of risk. This paper is intended to help guide the development of new experimental studies into the energy-risk trade-off. Received: 10 February 1995/Accepted after revision: 1 October 1995     

Synchrony in egg-laying and reproductive success of neighboring common murres,Uria aalge

Common murres (Uria aalge) are highly colonial; pairs often breed at the highest possible densities, in bodily contact with neighbors. At Bluff, a colony in western Alaska, we tested for synchrony in egg laying at various spatial scales and found little evidence for higher synchrony, either within study plots of 15–195 pairs, or within subplots containing several pairs, than among plots in a 5-year study. Egg laying of neighbors generally was more synchronous than expected based on overall frequency distributions in laying dates, however. Breeding success was positively correlated with the number of breeding neighbors and the number of neighbors tending eggs or nestlings at the time of egg laying. Breeding success of pairs with neighbors was positively related to the breeding success of neighbors. Pairs that produced eggs synchronously with at least one neighboring pair had higher success than those that began breeding either before or after their neighbors. Most reproductive failures at Bluff are due to accidental egg loss and predation on eggs by common ravens, Corvus corax, soon after laying. By occupying space where a raven might otherwise land and defending their own eggs, active breeding neighbors locally reduce the probability of egg predation. Active breeding neighbors also are less likely to flush and accidentally dislodge nearby eggs when disturbed than are nonbreeders. Murres breeding synchronously with neighbors have the highest assurance of the presence of active breeding neighbors both at the time of egg laying and throughout their reproductive attempts. Groups of neighboring murres can be considered small “selfish herds,” demonstrating by-product mutualism through their continued presence and defense of their own eggs and nestlings. Despite the advantages of breeding synchronously with neighbors, early breeding may often be favored, however. Received: 22 January 1996/Accepted after revision: 16 June 1996     

Different modes of resource variation provide a critical test of ideal free distribution models

Ideal free distribution (IFD) models are perhaps the group of mathematical models of behavior that have been the most widely and successfully applied by empiricists. These models can be applied to nearly any situation in which consumers compete—by any mechanism—for resources that are patchily distributed in their environment. Although IFD models have come to be broadly accepted, experiments that simultaneously test more than a single prediction are rare. Instead, investigators normally either test (1) for a relationship between the distribution of consumers and the distribution of resources or (2) whether average fitnesses are equal across resource patches. We conducted experiments with pea aphids (Acyrthosiphon pisum Harris) feeding on two patches of fava beans (Vicia faba L.) to fully independently parameterize an IFD model with interference competition and then test quantitative predictions about aphid spatial distributions and the payoffs of patch choice. We found a precise fit between aphids’ predicted and observed reproductive successes. Furthermore, by varying patch “quality” in two ways, we were able to show that aphid distributions vary with the mode of resource variation in the predicted manner: aphids (1) matched resources when patches varied in size but not quality and (2) overmatched the good patch when patches varied in quality but not size (predicted as a consequence of weak interference). The close correspondence between quantitative predictions of the model with observed behaviors suggests that IFD theory is a framework with more explanatory power than is generally appreciated.     

进一步保持和发扬我党的"真正优势"

本文在全面论述邓小平同志关于"共同的理想"和"铁的纪律"是我党"真正优势"光辉论断的基础上,指出目前我们在保持和发扬"真正优势"方面存在的不足,并认为中国共产党要顺利解决"两大历史性课题",必须进一步保持和发扬自己的"真正优势".