Spatially explicit farming system modelling for an efficient agri-environmental policy design

A mathematical programming model is developed and associated to a spatial pattern index (Ripley L-function) to analyse the optimal reserve design and implementation for the Little Bustard conservation in Plaine de Niort. The model structure corresponds to three spatial levels, fields, farm and landscape. Simple in terms of area representation it is detailed in term of farm behaviour and spatially explicit. The model is applied in a normative and in a positive way. The major findings of the normative approach relate to the trade-offs between the reserve pattern and its cost. It was found that the environmentally optimal reserve, which is randomly dispersed across the zone, is the most costly one. Within the positive approach, it is illustrated that the various reserve patterns generated within the normative approach can be obtained through relatively simple uniform contract structures. The most effective contract structure is a degressive set of two payments enabling all the farms to enrol at least a small share of their land.Biodiversity, spatial optimization, mathematical programming, agri-environmental policies, Tetrax tetrax, Agricultural and Food Policy, Environmental Economics and Policy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,

Spatially explicit farming system modelling for an efficient agri-environmental policy design

A mathematical programming model is developed and associated to a spatial pattern index (Ripley L function) to analyse the optimal reserve design and implementation for the Little Bustard conservation in Plaine de Niort. The model structure corresponds to three spatial levels, fields, farm and landscape. Simple in terms of area representation, it is detailed in terms of farm behaviour and spatially explicit. The model is applied in a normative and in a positive way. The major findings of the normative approach relate to the trade-offs between the reserve pattern and its cost. It was found that the environmentally optimal reserve, which is randomly dispersed across the zone, is the most costly one. Within the positive approach, it is illustrated that the various reserve patterns generated within the normative approach can be obtained through relatively simple uniform contract structures. The most effective contract structure is a degressive set of two payments enabling the farms to enroll at least a small share of their land.Biodiversity, spatial optimization, mathematical programming, Environmental Economics and Policy, Farm Management,

Belief revision and uncertain reasoning

When a new piece of information contradicts a currently held belief, one has to modify the set of beliefs in order to restore its consistency. In the case where it is necessary to give up a belief, some of them are less likely to be abandoned than others. The concept of epistemic entrenchment is used by some AI approaches to explain this fact based on formal properties of the belief set (e. g. , transitivity). Two experiments were designed to test the hypothesis that contrary to such views, (i) belief is naturally represented by degrees rather than in an all-or-nothing manner, (ii) entrenchment is primarily a matter of content and not only a matter of form, and (iii) consequently prior degree of belief is a powerful factor of change. The two experiments used Elio and Pelletier's (1997) paradigm in which participants were presented with full simple deductive arguments whose conclusion was denied, following which they were asked to decide which premise to revise

Testosterone Hormone Replacement Therapy: State-of-the-Art and Emerging Technologies

In the human male, testosterone is the major circulating androgen. The clinical effects of androgen are numerous, and testosterone deficiency is associated with a number of clinical abnormalities. At present, a variety of preparations containing testosterone is available for the treatment of androgen deficiency. Ideally, those treatments have to produce and maintain physiologic serum concentrations of the hormone. This article reviews the current existing testosterone dosage forms on the market with their advantages and drawbacks and examines new and emerging technology developments concerning this therapy. In particular, the latest innovations in transdermal delivery are explore

Combining Adaptive Coding and Modulation With Hierarchical Modulation in Satcom Systems

We investigate the design of a broadcast system in order to maximize throughput. This task is usually challenging due to channel variability. Forty years ago, Cover introduced and compared two schemes: time sharing and superposition coding. Even if the second scheme was proved to be optimal for some channels, modern satellite communications systems such as DVB-SH and DVB-S2 rely mainly on a time sharing strategy to optimize the throughput. They consider hierarchical modulation, a practical implementation of superposition coding, but only for unequal error protection or backward compatibility purposes. In this article, we propose to combine time sharing and hierarchical modulation together and show how this scheme can improve the performance in terms of available rate. We introduce a hierarchical 16-APSK to boost the performance of the DVB-S2 standard. We also evaluate various strategies to group the receivers in pairs when using hierarchical modulation. Finally, we show in a realistic case, based on DVB-S2, that the combined scheme can provide throughput gains greater than 10% compared to the best time sharing strategy

Asymptotic Analysis and Design of LDPC Codes for Laurent-based Optimal and Suboptimal CPM Receivers

International audienceIn this paper, we derive an asymptotic analysis for a capacity approaching design of serially concatenated turbo schemes with low density parity check (LDPC) codes and continuous phase modulation (CPM) based on Laurent decomposition. The proposed design is based on extrinsic mutual information evolution and Gaussian approximation. By inserting partial interleavers between LDPC and CPM and allowing degree-1 variable nodes under a certain constraint we show that designed rates are very close to the maximum achievable rates. Furthermore, we discuss the selection of low complexity receivers that works with the same optimized profiles

Improving broadcast channel rate using hierarchical modulation

We investigate the design of a broadcast system where the aim is to maximise the throughput. This task is usually challenging due to the channel variability. Modern satellite communications systems such as DVB-SH and DVB-S2 mainly rely on time sharing strategy to optimize throughput. They consider hierarchical modulation but only for unequal error protection or backward compatibility purposes. We propose in this article to combine time sharing and hierarchical modulation together and show how this scheme can improve the performance in terms of available rate. We present the gain on a simple channel modeling the broadcasting area of a satellite. Our work is applied to the DVB-SH standard, which considers hierarchical modulation as an optional feature.Comment: 5 pages, submitte

Effects of the addition of high-dose vitamin C to polyethylene glycol solution for colonic cleansing: A pilot study in healthy volunteers

AbstractBackground:Polyethylene glycol (PEG) solutions, with or without osmotic agents, are used to empty the large intestine before procedures such as colonoscopy or colonic surgery. Data concerning the effectiveness of vitamin C as an ingredient in colonic preparations are scant.Objective:The aim of this article was to assess the effectiveness, acceptability, and tolerability of 6 preparations of a standard PEG electrolyte solution containing different doses of PEG, vitamin C (as an osmotic agent), and sodium sulfate in colonic cleansing.Methods:This double-blind, randomized, 2-period crossover study was conducted at the Lariboisière Hospital, Paris, France. Healthy adult volunteers were randomly assigned to receive 2 of 6 colonic cleansing preparations, each containing different doses of PEG (100 or 125 g/L), vitamin C (0, 5, or 10 g/L, in the form of sodium ascorbate, ascorbic acid, or a mixture of both), and sodium sulfate (5 or 7.5 g/L), diluted in water to a volume of 2 L. Study drug administration was separated by a washout period of 7 to 15 days, after which the volunteers received an alternate preparation. Stools were collected for 10 hours after the start of solution ingestion. The primary efficacy end point was stool volume. Secondary end points included acceptability of taste, assessed using a 100-mm visual analog scale (VAS) (0 = excellent to 100 = execrable), taste criteria (saltiness, acidity, and sweetness, assessed on a 4-point Likert-type scale [0 = very pleasant to 3 = intolerable]) and tolerability (clinical effects [changes in body weight, blood pressure, heart rate, and nausea and vomiting] and biologic effects [changes in serum electrolytes, creatinine, hematocrit, and ascorbic acid]).Results:Thirty volunteers (15 men, 15 women; mean [SD] age, 29.8 [8.2] years [range, 20–45 years]) were enrolled and completed the study. Mean (SD) stool volume obtained with preparations containing 10 g/L of vitamin C did not differ significantly from the volume obtained without vitamin C (2.54 [0.54] L vs 1.93 [0.62] L; 95% CI, −0.13 to 1.47). Mean (SD) VAS scores for acceptability of taste ranged from 54.4 (25.0) (preparation E) to 74.4 (20.1) (preparation C) (P = 0.03 preparation E vs all other preparations). The only significant difference in taste criteria was in acidity, with preparation A being the least acidic according to patients' ratings on the VAS (1.4 [0.7] vs 1.8 [0.4] [mean of the other 5 preparations combined]; P = 0.04 preparation A vs all other preparations). Mild dehydration occurred in 6 subjects (1 for each preparation). No clinical or biological adverse effects were found.Conclusions:In this study of 6 colonic cleansing preparations in healthy volunteers, the use of high-dose vitamin C as an osmotic agent in addition to PEG did not significantly increase stool output. All 6 preparations were well tolerated