UTILIZATION OF RELATIVE LAND ALLOCATION IN THE CALIBRATION OF AGRICULTURE SUPPLY MODELS BY THE PMP APPROACH

This poster proposes a new procedure in agriculture supply modelling by the positive mathematical programming (PMP) approach. This approach is now widely used in last CAP reform simulations. However, simulation behaviour and performances of PMP procedures depend of the way parameters of the non linear total cost function in the objective function are recovered. We propose a new specification of the total cost function where land is explicitly considered as a fixed input. By using relative parts of land of the different activities this new PMP procedure permits to better capture production behaviour when economic conditions. It also permits to avoid a drawback of the early procedures concerning marginal activitiesPositive Mathematical Programming, CAP, Agricultural and Food Policy, Research Methods/ Statistical Methods, Q10, Q18,

On the Enforcement of a Class of Nonlinear Constraints on Petri Nets

International audienceThis paper focuses on the enforcement of nonlinear constraints in Petri nets. First, a supervisory structure is proposed for a nonlinear constraint. The proposed structure consists of added places and transitions. It controls the transitions in the net to be controlled only but does not change its states since there is no arc between the added transitions and the places in the original net. Second, an integer linear programming model is proposed to transform a nonlinear constraint to a minimal number of conjunc-tive linear constraints that have the same control performance as the nonlinear one. By using a place invariant based method, the obtained linear constraints can be easily enforced by a set of control places. The control places consist to a supervisor that can enforce the given nonlinear constraint. On condition that the admissible markings space of a nonlinear constraint is non-convex, another integer linear programming model is developed to obtain a minimal number of constraints whose disjunctions are equivalent to the nonlinear constraint. Finally, a number of examples are provided to demonstrate the proposed approach

Fuelwood consumption, restrictions about resource availability and public policies: impacts on the French forest sector

In the context of climate change and of increasing energy prices, the share of fuelwood in primary energy consumption may increase, especially in countries with large forest endowments. However, larger fuelwood consumption may have non-negligible impacts on forest sectors. This paper assesses those impacts for France using a new model of the French forest sector, and comparing four different policy options to boost fuelwood demand. First, supply- and demand-side policies yield very different outcomes, with a trade-off between trade balance and harvest intensity. Second, even a modest increase in fuelwood consumption leads to tensions over forest stock over time under pessimistic views about resource availability.forest sector modeling, fuelwood, bioenergy, public incentives.

Experience of a Single Center in NTBC Use in Management of Hereditary Tyrosinemia Type I in Libya

BACKGROUND: Hereditary Tyrosinemia type I (HTI) is a metabolic disease caused by deficiency of fumarylacetoacetate hydrolase enzyme.OBJECTIVES: This study reports beside its clinical and biochemical presentation, the outcome of NTBC [2- (2-nitro-4-trifloro-methylbenzoyl)-1, 3-cyclohexanedion] treatment of the disease and evaluates its biochemical markers in 16 pediatric Libyan patients.PATIENTS AND METHODS: The diagnosis was based on presence of high tyrosine levels in blood and succinylacetone in urine.RESULTS: The consanguinity rate was 81.2%, the median age at onset, at diagnosis and at starting treatment were 4.5, 8, and 9.5 months respectively. At presentation hepatomegaly, jaundice, rickets and high gamma glutamyl transferase (GGT) were observed in 87.5% of patients. All patients had extremely high alpha fetoprotein (AFP) and high alkaline phosphatase (ALP) levels. Fifteen patients were treated with NTBC, normalization of PT (Prothrombine time) was achieved in average in 14 days. The other biochemical parameters of liver function (transaminases, GGT, ALP, bilirubin and albumin) took longer to improve and several months to be normalized. Survival rate with NTBC was 86.6%. Patients who started treatment in a median of 3 months post onset observed a fast drop of AFP in 90.6% of patients (P = 0.003). Abnormal liver function and rickets were the common presentations, GGT was an early cholestatic sensitive test. ALP was constantly high even in asymptomatic patients.CONCLUSIONS: In HT1 a faster dropping of AFP is a marker of good prognosis

Retributing forest carbon vs. stimulating fuelwood demand insights from the French forest sector model

Forests can contribute to climate mitigation by sequestrating carbon in forest biomass andby replacing fossil-fuel with fuelwood, with potentially conflicting implications for forest management.The present paper assesses the mitigation and the economic impacts of a "stock" policy(payment for sequestration in situ), a "substitution" policy (subsidy to fuelwood consumption),and a combination thereof on the French forest sector. The policies are consistent in that theyare based on the same social cost of carbon. To do so, we use the French Forest Sector Model(FFSM), which combines a dynamic model of French timber resource, and a dynamic partial equilibriummodel of the French forest sector. Simulations show that over the 2010-2020 period,the stock policy is the only one that performs better than Business As Usual (BAU) in terms ofcarbon. Over this period of time, the cumulative substitution benefits of the substitution policyare not sufficient to offset the loss of carbon in standing forests. However, the stock policy hasalso negative impacts on consumers welfare, and increasingly high costs as carbon in excess ofBAU is accumulated in forests. Combining both policies brings intermediate results and is thusless effective than focusing on a single policy.carbon storage, biomass energy, forest sector modeling

Scalable Load Balancing Scheme for Distributed Controllers in Software Defined Data Centers

International audienc