PhD Elorri Arevalo
email: elorri.arevalo@inra.fr

Keywords:

Behavioural and physiological changes To ↑ growth and survival, alevins have to emerge

• When macroinvertebrate larvae are present at high densities

D i ~ Bernoulli (p.D i ) Logit(p.D i ) = μ j[i] + α j[i] V i + β j[i] H i + γ j[i] HW.C i + δ k[i]

Other unexpected sources of variation? δ k[i]

Water velocity?

Near-bed velocities (cm.s -1 )

Abiotic factors α j[i]

Gravel bed quality?

Coarse vs. Fine β j[i]

Individual size?

Head capsule widths (mm)

Biotic factors γ j[i]

Mean drift probability?

  elorri.arevalo@inra.fr Estimates of drift probabilities of the three invertebrate taxa undergoing a water velocity of 30 cm.s -1 in a fine substrate for medium width individuals. Results resonate with taxa's ecological features Baetis  Located above the gravel bed  Exposed to the current  Highest drift probability Simulium  Most rheophilic taxon  Able to withstand high flows  Lowest drift probability Chironomus  Buried in the substrate  No morphological adaptations to cope with flow Elorri AREVALO PhD Student -ECOBIOP elorri.arevalo@inra.fr Estimates of the drift probabilities of the three invertebrate taxa according to water velocity (cm.s -1 ) in a fine substrate for medium width individuals. Results resonate with taxa's ecological features Baetis  Located above the gravel bed  Exposed to the current  Highest drift probability Simulium  Most rheophilic taxon  Able to withstand high flows  Lowest drift probability Chironomus  Buried in the substrate  No morphological adaptations to cope with flow Only Chironomus drifted significantly more when water velocity increased BES Annual Meeting 11 -14 December 2016 Liverpool, United Kingdom Elorri AREVALO PhD Student -ECOBIOP elorri.arevalo@inra.fr Estimates of drift probabilities of the three invertebrate taxa according to gravel bed quality for mean width individual and mean water velocity. No significant differences  Granulometry = first-feeding trout areas  No dissimilarity in sheltering opportunities elorri.arevalo@inra.fr Estimates of the drift probabilities of the three invertebrate taxa according to head capsule width (mm) in a fine substrate and mean water velocity.Nothing for Baetis Small individuals drifting more  Simulium: high organic concentration needed to optimize their food aquisition? Chironomus: not able to resist the drag force of the current? Carried away by flow?

FLOW Maps of precipitation changes for Europe and Mediterranean in 2080-2099 in December to February

	CLIMATE CHANGE CLIMATE CHANGE CLIMATE CHANGE	Freshwater ecosystems FLOW Freshwater ecosystems
	• Geomorphology, habitat
	• Organisms distribution
	Atlantic coast of Europe: Atlantic coast of Europe: Atlantic coast of Europe:
	↑↑ precipitations in ↑↑ precipitations in ↑↑ precipitations in
	winter/spring winter/spring winter/spring
	↑↑ frequency and ↑↑ frequency and	↑↑ mean
	intensity of floods intensity of floods	discharge
	Maps of precipitation changes for Europe and Mediterranean in 2080-2099 in December
	to February -3 scenarios: SRES A1B (left), RCP4.5 (middle) and SRES A1B (right). -3 scenarios: SRES A1B (left), RCP4.5 (middle) and SRES A1B (right).
	IPCC, 2014 IPCC, 2014
	Elorri AREVALO
	PhD Student -ECOBIOP

elorri.arevalo@inra.fr Key variable:

Disruption of stream biota ↑↑ mean discharge BES Annual Meeting 11

		↓↓ abundance and diversity
		Up to 95% Up to 95% Up to 95%
			Argerich et al., 2004 Argerich et al., 2004 Argerich et al., 2004
		Macroinvertebrates:	Mesa, 2010 Mundahl & Hunt, 2011 Robinson et al., 2014 Mesa, 2010 Mundahl & Hunt, 2011 Mesa, 2010 Mundahl & Hunt, 2011 Robinson et al., 2014 Robinson et al., 2014
	CLIMATE CHANGE	Main food items of many Main food items of many
		running-water salmonids running-water salmonids
	↑↑ average flow level ↑↑ average flow level
	& water velocity & water velocity
		Our Objectives
	Infer consequences on food availability for fish	• Taxon? • Water velocity? • Gravel bed quality?
		• Individual size?

-14 December 2016 Liverpool, United Kingdom Elorri AREVALO PhD Student -ECOBIOP elorri.arevalo@inra.fr Extreme hydrological events ↑↑ frequency & intensity of FLOODS ↓↓ abundance and diversity 8 BES Annual Meeting 11 -14 December 2016 Liverpool, United Kingdom Elorri AREVALO PhD Student -ECOBIOP elorri.arevalo@inra.fr Extreme hydrological events ↑↑ frequency & intensity of FLOODS ↓↓ abundance and diversity CLIMATE CHANGE Effects on communities?? Lack of knowledge for non-scouring floods Macroinvertebrates: BES Annual Meeting 11 -14 December 2016 Liverpool, United Kingdom Elorri AREVALO PhD Student -ECOBIOP elorri.arevalo@inra.fr Extreme hydrological events ↑↑ frequency & intensity of FLOODS Propensity of invertebrates to drift/be scoured according to: CLIMATE CHANGE Effects on communities?? Lack of knowledge for non-scouring floods Macroinvertebrates: Main food items of many running-water salmonids 11 -14 December 2016 Liverpool, United Kingdom

Theodoropoulos et al., 2017

< Water column velocity < 4 m.s -1

BES Annual Meeting

To sum up … Implications for fish:

• ↘ of 2 preferred 0 + salmonids prey

• Starvation?

• Diet shifts?

• Switch in the hunting mode?

Resilience? Recolonisation?

↘ Growth & Survival


est destinée au dépôt

Global estimates of land photosynthesis inferred from the global budget of δ18O in atmospheric CO2: the crucial role of soil microorganisms

Jerome Ogee, Lisa Wingate

To cite this version:

Abstract

Quantifying terrestrial carbon storage and predicting the sensitivity of ecosystems to climate change relies on our ability to obtain observational constraints on photosynthesis and respiration at large scales (ecosystem, regional and global). Photosynthesis (GPP), the largest CO2 flux from the land surface, is currently estimated with considerable uncertainty (1--3).

Robust estimates of global GPP can be obtained from an atmospheric budget of the oxygen isotopic composition (δ 18 O) of atmospheric CO2, provided that we have a good knowledge of the δ 18 O signatures of the terrestrial CO2 fluxes [START_REF] Welp | Interannual variability in the oxygen isotopes of atmospheric CO 2 driven by El Niño[END_REF][START_REF] Wingate | The impact of soil microorganisms on the global budget of δ 18 O in atmospheric CO 2[END_REF]. The latter reflect the δ 18 O of leaf and soil water pools because CO2 exchanges "isotopically" with water [CO 2 +H 2 18 O⇔H 2 O+CO 18 O]. This exchange can be accelerated by the enzyme carbonic anhydrase (CA). In leaves, where CA is present and abundant, this isotopic equilibrium is reached almost instantaneously. As a consequence, and because soil and leaf water pools have different δ 18 O signatures, CO2 fluxes from leaves and soils carry very distinct δ 18 O signals and can thus be tracked from the fluctuations in the δ 18 O of atmospheric CO2 (δa). The accelerated isotopic exchange between CO2 and water due to CA activity has recently been shown to be a widespread phenomenon in soils as well [START_REF] Wingate | The impact of soil microorganisms on the global budget of δ 18 O in atmospheric CO 2[END_REF]. Across a range of ecosystems, we found that CO2 hydration was 10 to 1000 times faster than the un-catalysed rate, with highest values in the hottest ecosystems. At the global scale, accounting for soil CA activity dramatically shifts the influence of soil and leaf fluxes on δa, thus changing the estimates of terrestrial gross CO2 fluxes. In this talk I will present the current state of understanding of the environmental and ecological causes behind the variability in CA activity observed in soils and illustrate how this variability can influence our estimates of global GPP inferred from δa budgets.

02802107 Global estimates of land photosynthesis inferred from the global budget of δ 18 O in atmospheric CO 2 : the crucial role of soil microorganisms

	Jérôme Ogée and Lisa Wingate
	INRA EPHYSE UR1263, Bordeaux, France

Jerome Ogee, Lisa Wingate. Global estimates of land photosynthesis inferred from the global budget of δ18O in atmospheric CO2: the crucial role of soil microorganisms. COST Action FP0803 ('Belowground carbon turnover in European Forests') Final Conference, May 2013, Bordeaux, France. hal-


Mounia Moudjed
email: mounia.moudjed@let.ish-lyon.cnrs.fr

ON THE INTEREST OF INTRODUCING PERFORMANCE INDICATORS IN THE FRENCH URBAN TRANSPORT : A PROPOSAL FOR AN EUROPEAN BENCHMARKING ANALYSIS

Keywords: urban public transport regulation, indicators of performance, european benchmarking

The urban transport is one of the emblematic local sector that knows a double evolution in the european area. On the one hand, in some european countries, the decentralization reinforced the local regulation of the public services with a « competition for the market », by legitimating the role of the local communities (becoming authorities of transport). The reflexions on the measuring instruments of the performance fall under this quite precise context of the process of decentralization. This pleasing last to reconsider the local public management tools and specifically the statistical datas that the local communities will have to appropriate themselves. In the other hand, the liberalization, by the introduction of a european regulation with a « competition by the market » (tendering contracts), comes to upset the technical, lawful and economic conditions under which the local service is organized.

This evolution and the complexity of the contractual organization comes to redefine contours of the regulation of the public utility of the urban transport. Indeed, to the existing questions of competition and the contractual methods, comes to be grafted the performance and its measurement. Consequently, integrate the performance in the regulation of the sector becomes a necessity (we will understand by the regulation term the whole of the interventions of the authorities aiming at founding competition in a sector where it exists more or less according to countries and to reconcile the exercise of competition with the « missions of general interest »). This regulation by the performance must pass by a renewal of the mechanisms of incentive in public transport. It is not only a question of promoting competition, but also taking care that the objectives raising traditionally of the general interest can be achieved by measuring the effectiveness of the service in its contractual and competing environment.

But in this paper, we will see that this double evolution results in a different organization according to certain European countries (France, England, Norway, Sweden and Italy). Whereas in France, the idea to develop a regulation by the performance emerges, in other countries like England or Norway, the practice of the measurement of the performance of the public services is integrated for a long time and is much more systematic. All at least, the problems of the evaluation seem to remain, for certain European countries, in a second plan concerning the reflexions on the regulation of the public services in local matter. In France, it seems to appear indirectly in the contractual processes and in national and local statistical tools. Furthemore, apart from England where privatization begin quickly because of the failures of the sector and the authority of the government, the other european countries engaged in dispersed order in experiments of privatization. Italy prepares there but the political consensus necessary to this opening appears difficult to find.

Complex dimension in the public services, the performance of a service can be declined in different economic configurations according to countries, but the idea will be retained that the research and the measure of the efficiency of the public utility is an important and necessary stage. By mobilizing this economic criterion, we are able to show better the maturity and the capacity of the local authority in the management of his urban network. So, the comparative analysis will require to carry out a decomposition by level of actors and not simply wondering about the only definition of the economic criteria of measurement mobilized. We will show how some countries as Sweden are able to exceed the only unilateral performance of market and production (technical and financial) of the operator and the service (from the physical point of view). In fact, some countries succed in the measurement of a trilateral performance where the local authority and the users must be implied as much as the operator of transport and to have measuring instruments of the total performance of the service.

By establishing a monographic analysis by comparing in the space the measurement of the urban transport performance by means of the use of indicators (France, England, Italy, Norway and Sweden), the aim of the paper is double. First, show why and how, according to the recent evolutions in the european urban transport, the dimension of the performance, in the regulation of the sector, is taken into account in the different european areas. Secondally, it is about to compare the different european areas on the compromise performance-competition, the introduction of indicators as instruments of measurement.

In the Scandinavian countries, it would be necessary to be interested in what is done in Sweden and in Norway. In Sweden, the indicators of performance are divided by various cities and networks to ensure benchmarking and of collective stimulation for better performances. With the Swedish Customer Barometer, a barometer of satisfaction, it makes it possible to make all kinds of comparisons between the urban transport areas. Also, it is the subject of monthly reports and ratios on Internet. The practice of performance evaluation in urban public transport in Norway is not very developed. The recent introduction of a collection of statistical datas could make evolve the situation. England represents the Anglo Saxon model. In England, national authorities promote the principle of value for money, that is to say the social utility of the public money and the role of the user in the processus of performance measurement. Deregulated sector, independent authorities are in charge of the measurement of the performance (the Audit Commission). In Italy, it is about for the moment of a nstitutional reorganization and beginning of entry in the competition which will change certainly concerning the measurement of the performance.

This reflexion allowed us take some conclusions for the french urban transport. That is to say, the research of a new instrumentation by introducing indicators of performance. But for France, the interest of the foreign experiments appears balanced. On one side, the variety of the foreign models multiplies the scenarios of which it can be inspired. On other side, the intensity of the legal and cultural differences encourages with prudence in the transpositions. In France, the State often propose more or less strong control for the local authorities. Whatever is the degree and the methods of intervention of the public power, it was done with a major objective : the constitution of a transport system covering the territories and answering to missions of public utility of continuity, adaptability and equality.

The final objective of this study is to arrive to a typology of the practices of evaluation, but, also to be able to draw up differents models of regulation by the performance of urban public transport and to see what could be transfered to the french model. The choice of the countries is justified by the following points : some countries as Italy or France are a typical example of communal management, other countries as England are typical example of national and and privatized management for public transport and its measurement of performance.


domain: sdv info

text:
Bénédicte Lebret

Marie Damon

Towards the Identification of Molecular Markers of Pork Quality

Background : Meat Quality -2

• But...

• High variability of MQ • Muscle traits high sensory quality ?

• Q-Porkchains: Identify markers of MQ control tools using a wide approach : omics methods Biochemistry, expression of target genes

Other genes or proteins involved in MQ?

Functional genomics for MQ -Danish commercial pork chain produced for validation, n=100

• 2.3 Validation on the whole data set

Step 1. Database set-up -1

Large White LW conventional Step 1. Relationships gene expression -MQ

• Database : high variability of MQ traits Step 2. Within-chain validation Step 2. Wide validation -1

• Duroc crossbred, CM and F, 110 kg, n=40 13 correlations validated on a different pork chain 10 genes and 5 MQ traits R² up to 20 %, same range as within-chain validation

Step 2. Wide validation -2

• Commercial Danish pork chain -L. Kristensen, DMRI

  Rearing conditions: feeding, housing,... Slaughter conditions and meat processing • Factors influencing MQ • i.m. fat, glycogen, myofibers, pH decline, proteolysis...

  Database set-up -2 Longissimus muscle, 150 kg, Replicate 1 Meat Quality pH1, pHu, drip loss, colour (L*, a*, b*, C*, h°), IMF, glycolytic potential Shear Force Tenderness, juiciness, flavour Correlations between gene expression and MQ data:

•

  The authors gratefully acknowledge from the European Community financial participation under the Sixth Framework Programme for Research, Technological Development and Demonstration Activities, for the Integrated Project Q-PORKCHAINS FOOD-CT-2007-036245. Q-PORKCHAINS FOOD-CT-2007-036245.

8% chosen for wide validation step 58 correlations validated on 100 LW and B pigs 25 genes and 13 MQ traits

	Drip loss	15	25
	Colour: L*	6	25
	a*	4	20
	b*	3	24
	h°5	23
	Glycolytic potential	4	24
	Intramuscular fat	6	26
	Shear force	2	13
	Tenderness 21 genes, R 2 >	1	8
	Juiciness	1	14

• Experimental LW & B, replicates 1 + 2, 100 pigs 58 correlations validated on 100 LW and B pigs : pH, drip loss, colour, GP, IMF, shear force, tenderness, juiciness R² up to 33 %

Acknowledgement

Models for 12 MQ traits: 3 to 9 genes, 24 < R² < 56%

Many common genes

• Multiple regressions: 3 pork chains, all correlated genes


Nancy research group on tree productivity, soil-plant interactions and global changes Projects Tree scale: tree growth, wood formation, tree nutrition and ecophysiological response to climatic drivers and to management Stand scale: monitoring and modelling of energy, carbon, water, nutrient cycles and stand growth. Large range of ecosystems Regional and national scale: functioning of the different ecosystem types, tree species growth and distributions

Infrastructures

  French network of eddy-flux sites, linked to international networks: CarboEurope, CarboExtreme, Expeer, Fluxnet French network of intensive biogeochemical study sites linked to tropical sites (Congo, Brazil) and International Slash Management network (CIFOR) In complement to the intensive monitoring sites: in situ experiments including ecosystem manipulations (species effects, forest management, rain exclusion experiments)  Networks of forest management (GIS-COOP) and provenance trials (PlantaComp)  Strong partnership with IFN (National forest Inventories)  Data bases: SOERE (France), CarboEurope (EU), Fluxnet (world)  Lab Facilities (PTEF, LabMobile, Pollux) Investigated ecosystems: Ø Ecosystem types in temperate, wet and dry tropical areas Ø Forests (pure and mixed), plantations, short rotation coppices Ø In cooperation with other groups: grasslands and crops ancy -Freiburg -Zurich, 27-03-2012 Nancy research group on tree productivity, soil-plant interactions and global changes ancy -Freiburg -Zurich, 27-03-2012 Some results at Tree scale Life strategies in intra-annual dynamics of wood formation: example of three conifer species in a temperate forest in North-east France [Cuny, Rathgeber, Lebourgeois, Fortin, Fournier, Tree physiology. In Press.] interactions and global changes ancy -Freiburg -Zurich, 27-03-2012 Some results at stand scale (Organic matter stabilization, interaction C an Remusat et al. Environmental Sciences and Technology (2012) STXM is a transmission technique that maps C, N, and, through acquisition of NEXAFS spectra, can determine the type of C and N functional groups Image 285 eV Image 300 eV Hypothesis : The preservation of N derived from litter would be favored by its incorporation in microbial metabolites. The microbial compounds, often polar or charged, are more able to interact with protective mineral surfaces than litter compounds. Incubation of 15N labeled litter material for 12 yrs (initial 15N=5700‰) After 12 yrs, NanoSIMS identification of a labeled hotspot derived from the litter : 15N= 213±132‰) carboxyl-C with amide In this particle, the 15N hotspot is in an area which STXM spectrum is similar to microbial cell material (mixture of amino-sugars and proteins) Nancy research group on tree productivity, soil-plant interactions and global changes ancy -Freiburg -Zurich, 27-03-2012 Some results at stand scale (flux of nutrients -seasonal variations) Spruce Beech SEASONAL EFFECT: Shift of the microbial communities along the seasons 16S rRNA-based surveys of the culturable bacterial communities during autumn and spring in beech and spruce stands (Breuil-Chenue) Functional screening of the culturable bacterial communities capable of weathering minerals along the seasons in beech and spruce stands (Breuil-Chenue) Confirmation of the mineral weathering efficacy of the Burkholderia genus Seasons differentially impact the functional and taxonomic diversity of the culturable bacterial communities in beech and spruce stands of GPP are allocated to the the belowground parts 2/3 of this carbon is released through respiration The autotrophic respiration represents 50 to 70% of total soil respiration 0allocation to aboveground compartments TBCF : Carbon allocation to belowground compartments Nancy research group on tree productivity, soil-plant interactions and global changes ancy -Freiburg -Zurich, 27-03-2012 Some results at Stand scale (nutrient cycling and ecosystem durability Forest productivity in a changing environment. A multi-scale assessment of recent productivity variations based on the national forest inventory (IFN) data and environmental interpretations. (planned on 5/04/2012) soil-plant interactions and global changes Infrastructures Long term and intensive study sites Complementary experiments -Eddy-flux sites in 2 beech forests:Hesse (1996-), Montiers (2012-) and in the tropical rainforest --nutrient cycling in four sites (Breuil, Azerailles, Clermont, Montiers) -Strong cooperation with CIRAD on carbon, water and nutrient cycling in tropical sites (Congo, Brazil) -In those sites, intensive measurements of biomass, growth, litter production, soil properties and functioning (water, carbon, nutrients) -Water uptake within and among species: use of isotopic tools, under natural abundance and water labelling -Carbon and nutrient cycling in forest ecosystems: carbon, nitrogen and cations labelling, isotope spectrometry, multilabelling experiments -Carbon and water reserves in trees -Trees response to water shortage: rain exclusion experiments; trees response to slash

C, ‰)~2‰ phD J. Toillon / ANR SYLVABIOM

species, Basal area increment(BAI)

Nancy research group on productivity, soil-plant interactions and global changes

Long term and experimental sites

GIS COOP

Large network crossing intensity of silviculture and soil fertility for 5 tree species


Nathalie Le Floc'

Impact of health decline on protein and amino acid metabolism: what's the implication on amino acid requirements in swine?

Introduction

Health preservation is one of the main priorities and a constant challenge for swine production. Indeed, health decline and diseases are responsible for an increase in production costs due to mortality and reduced performance and feed efficiency. A wide range of health problems can be described. Some of them are caused by major specific pathogens acting alone or in combination with other pathogens. Other kinds of pig diseases, also named "production diseases", are caused by more or less opportunistic microbes that can become pathogenic when associated with social and climatic conditions [START_REF] Wellock | Predicting the consequences of social stressors on pig food intake and performance[END_REF] , degree of hygiene of the environment [START_REF] Floc | A moderate inflammation caused by the deterioration of housing conditions modifies Trp metabolism but not Trp requirement for growth of post-weaned piglets[END_REF][START_REF] Williams | Effect of chronic immune system activation on nitrogen retention, partial efficiency of lysine utilization, and lysine needs of pigs[END_REF] and practices such as diet changing, pig mixing, transfer from a building to another or weaning [START_REF] Pastorelli | Sanitary housing conditions modify the performance and behavioural response of weaned pigs to feed and housing-related stressors[END_REF] . Production diseases are thus clearly multifactorial, and this makes their management very complex.

Medication based on antibiotics are still used systematically and preventively to limit the negative consequences of production diseases. The reduction of their utilization is a challenge for the development of sustainable pig production systems preserving health, high performance and with reduced environmental impact. The role of nutrition is clearly questioned because it may be one of the solutions that contribute to limit medication through preserving health and performance. Indeed, health and nutrition are strongly connected. First, because health disturbances impact on the different components of nutrition function, i.e. feed intake, digestion, and metabolism; and second, because nutrition determines the organism's ability to maintain or to restore homeostasis in response to health disturbances. In this review, we will examine how and to what extent health impacts on performance and nutrition of swine, with a special focus on amino acids (AA). Indeed, AA metabolism is modified by health disturbances, as a consequence that AA are repartitioned between growth and body defences. If all AA constituting proteins are impacted by re-partitioning, some AA deserve a specific attention because of their role in pathways connected to immune responses and health preservation.

1/ How and how much health decline reduces performance?

Growth performances in commercial farms are usually lower compared to what is determined by the genetic potential of the animals. If environmental and housing conditions are responsible for these differences, the effect on performance are partly associated to the stimulation of the immune system that impacts on health status of pigs [START_REF] Johnson | Inhibition of growth by pro-inflammatory cytokines: an integrated view[END_REF] inducing reduction in feed intake, digestive disturbances, and metabolic changes such as increased energy expenditure, body temperature, and body protein turnover [START_REF] Black | The thermal and infectious environment[END_REF] .

The reduction in feed intake induced by health decline is the response that is the most frequently reported. The amplitude of feed intake reduction varies from complete anorexia in case of clinical disease to much more moderate feed intake reduction for subclinical infection [START_REF] Sandberg | A model for predicting feed intake of growing animals during exposure to pathogens[END_REF] . For instance, a moderate inflammatory response caused by poor hygiene reduces feed intake by 5 to 10% compared to control pigs [START_REF] Floc | A moderate inflammation caused by the deterioration of housing conditions modifies Trp metabolism but not Trp requirement for growth of post-weaned piglets[END_REF][START_REF] Williams | Effect of chronic immune system activation on nitrogen retention, partial efficiency of lysine utilization, and lysine needs of pigs[END_REF] . Different mechanisms can be responsible for the reduction in feed intake, including a direct effect of inflammatory cytokines synthesized by the activated immune cells. The interleukin IL-1β is one of the main factor involved in the feed intake regulation [START_REF] Johnson | Immune and endocrine regulation of food intake in sick animals[END_REF] . Injected in the brain or in the peripheral blood, IL-1β induced anorexia and sickness behavior [START_REF] Kelley | Cytokine-induced sickness behavior[END_REF] . TNF-α, another pro inflammatory cytokine, synergizes with IL-1β to suppress feeding. Cytokines may also reduce feed intake through their action on the digestive tract motility. Alternatively, feed intake may be lowered as a consequence of the reduced growth rate. Pigs with a lower growth rate have indeed lower requirement and appetite than pigs growing faster. This explanation is probably relevant for explaining the long lasting reduction in feed intake and growth rate reported during chronic subclinical diseases.

Impaired digestion and absorption capacity is the second mechanism responsible for decreased growth performance [START_REF] Coop | Nutrition-parasite interaction[END_REF] . Bacterial and parasitic infections targeting the gut epithelia cause intestinal cell damage and increase endogenous secretions [START_REF] Sandberg | The effects of pathogen challenges on the performance of native and immune animals: the problem of prediction[END_REF][START_REF] Hale | Influence of an experimental infection of ascaris suum on performance of pigs[END_REF] . This in turn affects feed digestion and nutrient absorption thereby reducing the availability of AA and energy for growth. Such gut disturbances may also contribute to reduce feed intake because of associated pain and discomfort. At least, diarrheas also contribute to the reduction in growth rate because of induced malabsorption and water loss.

Finally, part of the reduction in growth rate result from the nutritional cost associated with the stimulation of the immune system [START_REF] Sandberg | The effects of pathogen challenges on the performance of native and immune animals: the problem of prediction[END_REF] . Indeed, immune system stimulation requires energy, AA and trace elements for the proliferation of immune cells, synthesis of cytokines, antibodies, and acute phase proteins [START_REF] Klasing | Nutritional modulation of resistance to infectious diseases[END_REF] . This is supported by changes in metabolism and nutrient fluxes leading to changes in nutrient partitioning [START_REF] Klasing | Avian macrophages: regulators of local and systemic immune responses[END_REF] caused by cytokines and hormones. During immune and inflammatory responses, metabolic changes are associated with an increase in basal metabolic rate, increased energy utilization and a switch from glucose to fatty acids and AA as a preferred energy source by many tissues, redistribution of iron, zinc, and copper within the body for the hepatic synthesis of metallothionein, ferritin, and ceruloplasmin and release of hormones such as insulin, glucagon, and glucocorticoids [START_REF] Klasing | Monokines in growth and development[END_REF] . Hyperinsulinaemia and hyperglycaemia are commonly observed during inflammation and are a characteristic of reduced muscle insulin sensitivity [START_REF] Beisel | Metabolic effects of infection[END_REF] .

A recent paper [START_REF] Pastorelli | Meta-analysis of feed intake and growth responses of growing pigs after a sanitary challenge[END_REF] reported a meta-analysis carried out to quantify the feed intake and growth responses of growing pigs after different sanitary challenges that reproduced production diseases. A database was constructed using 122 published experiments reporting the average daily feed intake (ADFI) and average daily gain (ADG) of pigs submitted to six sanitary challenges: digestive bacterial infections, poor hygiene conditions, lipopolysaccharide (LPS) challenges, contaminations with mycotoxins, parasitic infections and respiratory diseases. All challenges resulted in a reduction in feed intake and ADG but the amplitude of the reduction differed between challenges. The figure 1 represents the relationship between the change in growth and feed intake of the challenged pigs relative to that of a control group. The strongest responses were reported for mycotoxins, respiratory diseases, and digestive bacterial infections (8 to 23% reduction in ADFI and 16 to 29% reduction in ADG). As discussed above, the growth reduction is partly caused by a reduction in feed intake but also to changes in digestion and metabolism. Indeed, a 10% reduction in ADFI resulted in a 10 to 43% reduction in ADG for mycotoxins and digestive bacterial infections, respectively. More than 70% of the reduction in ADG could be explained by the reduction in ADFI for mycotoxins, LPS challenge and respiratory diseases, while for digestive infections and poor hygiene, a large proportion of the reduction in ADG was due to an increase in maintenance requirements, i.e. requirement not associated with a reduction in feed intake, suggesting digestive and metabolic changes. Indeed, for poor housing conditions, conditions that reproduce a chronic immune challenge (figure 1b), the quadratic regression between ADG and ADFI indicates that the difference in ADG increased with the difference in ADFI between challenged and control pigs. Consequently, the more the ADFI decreased in challenged pigs, the more the feed efficiency, i.e. associated with a reduction in feed intake, was reduced compared with that of the control group indicating that a greater proportion of feed intake is used to meet maintenance requirements. From [START_REF] Pastorelli | Meta-analysis of feed intake and growth responses of growing pigs after a sanitary challenge[END_REF] .

2/ Consequences of health decline on protein and amino acid metabolism

Tissue protein metabolism

Changes in protein metabolism occurring during infection and inflammation have been extensively documented in many species. Protein accretion in the skeletal muscle is impaired during immune challenge because of simultaneous increased protein breakdown and decreased protein synthesis [START_REF] Breuillé | A sustained rat model for studying the long-lasting catabolic state of sepsis[END_REF][START_REF] Voisin | Muscle wasting in a rat model of long-lasting sepsis results from the activation of lysosomal, Ca2 +-activated, and ubiquitin-proteasome proteolytic pathways[END_REF][START_REF] Klasing | Changes in protein degradation in chickens due to an inflammatory challenge[END_REF] . Inflammatory cytokines like TNF-α acts directly on skeletal muscle to inhibit muscle protein synthesis [START_REF] Cooney | Interleukin-1 receptor antagonist prevents sepsis-induced inhibition of protein synthesis[END_REF] . Moreover, TNF-α reduces the efficacy of hormones such as IGF-I and insulin to stimulate protein synthesis [START_REF] Broussard | Cytokine-hormone interactions: tumor necrosis factor alpha impairs biologic activity and downstream activation signals of the insulin-like growth factor I receptor in myoblasts[END_REF] . Additionally, cytokines enhance the rate of skeletal muscle protein degradation [START_REF] Zamir | Reduced muscle protein breakdown in septic rats following treatment with interleukin-1 receptor antagonist[END_REF][START_REF] Garcia-Martinez | Tumour necrosis factor-a increases the ubiquitinization of rat skeletal muscle proteins[END_REF] and the efficacy of insulin to decrease muscle protein breakdown is reduced during infection [START_REF] Hasselgren | Regulation by insulin of muscle protein metabolism during sepsis and other catabolic conditions[END_REF][START_REF] Vary | Differential regulation of skeletal muscle protein turnover by insulin and IGF-I after bacteremia[END_REF] . Increased myostatin mRNA, a negative regulator of muscle mass, in skeletal muscle was reported in pigs with a respiratory infection [START_REF] Escobar | Decreased protein pccretion in pigs with viral and bacterial pneumonia is associated with increased myostatin expression in muscle[END_REF] . Amino acids released from muscle protein breakdown are partly degraded and converted into urea. However, AA are also used to support body defences.

In contrast to what is described in muscle, protein synthesis is increased in the liver mainly because of the increased acute-phase protein (APP) synthesis. These proteins serve important functions in restoring homeostasis after infection or inflammation [START_REF] Moshage | Cytokines and the hepatic acute phase response[END_REF] . These include haemostatic functions, microbicidal and phagocytic functions, antithrombotic properties, and antiproteolytic actions. During inflammation, APP plasma concentrations increase 2-to 100-fold depending on the protein, the animal species and the challenge, while their synthesis increases in greater proportion. For example, in pigs injected with turpentine, fibrinogen plasma concentrations increase by 30% and fibrinogen synthesis increases by 140% [START_REF] Jahoor | Chronic protein undernutrition and an acute inflammatory stimulus elicit different protein kinetic responses in plasma but not in muscle of piglets[END_REF] . Therefore, the increase in APP synthesis may require large amount of AA. The pro inflammatory cytokine IL-6 acts in synergy with IL-1 on the liver, but IL-6 is considered as the primary initiator of the liver acute-phase response [START_REF] Marinkovic | IL-6 modulates the synthesis of a specific set of acute phase plasma proteins in vivo[END_REF] . Glucocorticoids are known to exert an anabolic effect on the liver [START_REF] Pedersen | Protein synthesis in liver following infusion of the catabolic hormones corticosterone, epinephrine, and glucagon in rats[END_REF] and glucocorticoids alone are able to induce the secretion of some APP such as α1 glycoprotein acid, but generally, they act as a permissive or synergetic factor to the action of cytokines [START_REF] Marinkovic | IL-6 modulates the synthesis of a specific set of acute phase plasma proteins in vivo[END_REF] . This explains that increases in APP concentrations have been reported in response to both physical and psychological stressors in pigs [START_REF] Murata | Current research on acute phase proteins in veterinary diagnosis: an overview[END_REF][START_REF] Piñeiro | Characterisation of the pig acute phase protein response to road transport[END_REF][START_REF] Salamano | Changes in haptoglobin, C-reactive protein and pig-MAP during a housing period following long distance transport in swine[END_REF] and not only to immune challenges.

Amino acid partitioning during immune challenges and inflammation

The modifications of tissue protein metabolism described when health is challenged lead to changes in AA partitioning between growth and tissues and cells involved in health maintenance like the immune responses. The term nutrient partitioning refers to the process by which nutrients are channelled in various proportions to different metabolic functions [START_REF] Friggens | Towards a biological basis for predicting nutrient partitioning: the dairy cow as an example[END_REF] . This concept is notably relevant when it addresses the competition between productive functions and immune and defence functions, that are traditionally regarded as part of maintenance requirements. Some experimental data indicate that there may be competition for nutrient resources between the immune system and the reproductive functions [START_REF] Houdijk | Nutrient partitioning between reproductive and immune functions in animals[END_REF] but few data are available for young growing animals. Coop & Kyriazakis [START_REF] Coop | Nutrition-parasite interaction[END_REF] proposed a nutrient partitioning framework to describe the concept of prioritization for the allocation of scarce nutrients between different functions, including immune functions during parasitic diseases. Nutrient scarcity refers to situations where dietary nutrient supplies were not sufficient to meet maintenance and productive requirements. Briefly, for growing animals (Table 1), once immunity has been acquired, nutrients are allocated firstly to meet the maintenance functions, then the growth functions and finally the expression of acquired immunity. This means that growth could have the priority over immunity for nutrient utilization and that nutrient supplementation may improve the expression of immunity and body defences. For younger "naïve" animals, it can be expected that nutrient supplementation may be useful to improve growth once requirements for acquisition of immunity have been met. Table 1. Proposed order of partitioning of scarce resources to body functions in a growing animal. The acquisition (naïve animals) and expression (immune animals) phase of immunity are considered separately. Adapted from [START_REF] Coop | Nutrition-parasite interaction[END_REF] .

Acquisition phase "Naïve animals"

Expression phase "Immune animals" Analysis of plasma AA responses to different challenges provides some indications for evaluating the changes in AA partitioning when health is challenged. Lower plasma AA concentrations have been reported in pigs with enterotoxigenic Escherichia coli peritonitis or with chronic lung inflammation, respectively, compared to healthy pigs [START_REF] Melchior | Chronic lung inflammation affects plasma amino acid concentrations in pigs[END_REF][START_REF] Yoo | Glutamine supplementation maintains intramuscular glutamine concentrations and normalizes lymphocyte function in infected early weaned pigs[END_REF] . The decrease in AA concentrations following inflammatory diseases could reflect a decrease in feed consumption and in absorption for the first study [START_REF] Melchior | Chronic lung inflammation affects plasma amino acid concentrations in pigs[END_REF] . In the second experiment [START_REF] Yoo | Glutamine supplementation maintains intramuscular glutamine concentrations and normalizes lymphocyte function in infected early weaned pigs[END_REF] , because healthy and sick pigs were pair fed, this means they ate the same amount of feed, decrease in plasma AA concentrations can be explained by a greater AA utilisation, including AA catabolism, AA incorporation into proteins other than muscle protein, and AA conversion into specific molecules. For instance, the decrease in plasma tryptophan can be attributed to the synthesis of APP which are tryptophan rich proteins [START_REF] Reeds | Do the differences between the amino acid compositions of acute-phase and muscle proteins have a bearing on nitrogen loss in traumatic states?[END_REF] . This is further supported by results obtained in humans showing negative correlations between plasma tryptophan concentrations and the plasma concentrations of APP, transferrin, haptoglobin [START_REF] Maes | Relationships between lower plasma L-tryptophan levels and immune-inflammatory variables in depression[END_REF] and fibrinogen [START_REF] Preston | Fibrinogen synthesis is elevated in fasting cancer patients with an acute phase response[END_REF] . Moreover, indoleamine 2,3 dioxygenase (IDO), a rate limiting enzyme for the catabolism of tryptophan into kynurenine, was also found to be induced by the cytokine interferon-γ [START_REF] Mackenzie | Interferon-gamma-induced activation of indoleamine 2,3-dioxygenase in cord blood monocytederived macrophages inhibits the growth of group B streptococci[END_REF] and by inflammation in pigs [START_REF] Melchior | Is tryptophan catabolism increased through indoleamine 2,3 dioxygenase activity during chronic lung inflammation in pigs ?[END_REF][START_REF] Floc | Dietary tryptophan helps to preserve tryptophan homeostasis in pigs suffering from lung inflammation[END_REF] . Thus, the low plasma tryptophan concentrations can also be caused by an increase in tryptophan catabolism. However, such a decline in tryptophan concentration was not reported when pigs were fed a tryptophan supplemented diet [START_REF] Floc | Dietary tryptophan helps to preserve tryptophan homeostasis in pigs suffering from lung inflammation[END_REF] . Plasma AA concentrations are thus not necessarily indicative of metabolic changes because concentrations result from dynamic metabolic fluxes, which are influenced by many factors. Few studies have examined the consequences of health challenge on AA fluxes between tissues or metabolic pathways. Severe illness is associated with a depletion of plasma and muscle glutamine pool and increased plasma glutamine flux, suggesting that the requirement for glutamine would increase in a catabolic state [START_REF] Ziegler | Potential role of glutamine supplementation in nutrition support[END_REF] . In pigs, surgery and LPS injection increased glutamine release from the hindquarter and intestine, while glutamine uptake by the liver and spleen increased [START_REF] Bruins | Endotoxemia affects organ protein metabolism differently during prolonged feeding in pigs[END_REF][START_REF] Deutz | Postoperative changes in hepatic, intestinal, splenic and muscle fluxes of amino acids and ammonia in pigs[END_REF] . In septic rats, plasma cysteine flux measured during the constant infusion of labelled cysteine is increased compared to that in pair-fed control rats. This is explained by a concomitant increase in cysteine incorporation into the tripeptide glutathione and APP [START_REF] Malmezat | Metabolism of cysteine is modified during the acute phase of sepsis in rats[END_REF] . Moreover, a reduction of cysteine catabolism and an increase in cysteine transsulfuration from methionine were also reported, mechanisms that probably preserve the availability of cysteine for glutathione synthesis by the liver [START_REF] Malmezat | Methionine transsulfuration is increased during sepsis in rats[END_REF][START_REF] Malmezat | Glutathione turnover is increased during the acute phase of sepsis in rats[END_REF] . Recently, very similar results have been reported in growing pigs, for which repeated injections of LPS increased the conversion of cysteine into non protein compounds, namely glutathione and taurine, while cysteine catabolism into sulfate decreased [START_REF] Rakhshandeh | Immune system stimulation alters plasma cysteine kinetics in growing pigs[END_REF][START_REF] Rakhshandeh | Immune system stimulation increases reduced glutathione synthesis rate in growing pigs[END_REF] . Intestinal disorders also induce changes in AA fluxes. Experimental ileitis induced in minipigs increased liver and ileal GSH fractional synthesis rate from cysteine [START_REF] Rémond | Cysteine fluxes across the portal-drained viscera of enterally fed minipigs: effect of an acute intestinal inflammation[END_REF] and arterial threonine uptake by the gastrointestinal tract [START_REF] Rémond | Intestinal inflammation increases gastrointestinal threonine uptake and mucin synthesis in enterally fed minipigs[END_REF] . Moreover, during its intestinal absorption, more than one half of orally supplied threonine is extracted in first-pass by the small intestine of young pigs [START_REF] Floc | Catabolism through the threonine dehydrogenase pathway does not account for the high first-pass extraction rate of dietary threonine by the portal drained viscera in pigs[END_REF][START_REF] Van Der Schoor | The high metabolic cost of a functional gut[END_REF] . Consequently, the small intestine would have the priority over other tissues (liver, carcass and colon) when threonine is not adequately supplied by the feed and/or during digestive inflammation. The high threonine extraction by the small intestine is an important nutritional question, notably because it determines threonine availability for tissues depending on threonine supplied by the blood only [START_REF] Hamard | A moderate threonine deficiency affects differently protein metabolism in tissues of early-weaned piglets[END_REF] .

Amino acid utilization and functions during immune challenges and inflammation

Health decline modifies AA partitioning between growth and metabolic responses that support immune functions and body defences. If they are not catabolized, AA provided by feed and accelerated muscle protein catabolism are used as substrates for gluconeogenesis and immune cell proliferation. As indicated above, they can serve as substrates for the synthesis of APP in the liver and also immunoglobulin and mucins in the intestine. Moreover, some AA play specific roles closely related to immune response regulation or in other processes associated with body defences [START_REF] Floc | Modifications of protein and amino acid metabolism during inflammation and immune system activation[END_REF] .

Whereas many papers described the relationships between AA and immunity or body defenses, very few showed a clear relationship between AA dietary supplies and pig health. Glutamine is not considered as an essential amino acid for growth. However, many data indicate that this AA is essential for rapidly dividing cells like lymphocytes and enterocytes [START_REF] Windmueller | Uptake and metabolism of plasma glutamine by the small intestine[END_REF][START_REF] Calder | Glutamine and the immune system[END_REF] . In vitro, glutamine modulates immune functions of cultured lymphocytes and enterocytes [START_REF] Coëffier | Influence of glutamine on cytokine production by human gut in vitro[END_REF][START_REF] Yaqoob | Glutamine requirement of proliferating T lymphocytes[END_REF] . In pigs, dietary supplementation with 1% glutamine prevented jejunal atrophy occurring during the first week postweaning [START_REF] Wu | Dietary glutamine supplementation prevents jejunal atrophy in weaned pigs[END_REF] . In the same species, glutamine supplementation was also efficient to preserve an optimal immune function during an infection [START_REF] Yoo | Glutamine supplementation maintains intramuscular glutamine concentrations and normalizes lymphocyte function in infected early weaned pigs[END_REF] . Cysteine, a sulphur AA derived from methionine, is the main limiting factor for the synthesis of glutathione [START_REF] Grimble | Immunonutrition: role of sulfur amino acids, related amino acids, and polyamines[END_REF][START_REF] Cho | Tissue glutathione as a cyst(e)ine reservoir during cysteine depletion in growing rats[END_REF] , a tripeptide (Lglutamyl-L-cysteinyl-glycine) involved in the intracellular antioxidant defences. Depletion of glutathione pool has been reported in pigs suffering from inflammation, this phenomenon being clearly aggravated for low protein intake [START_REF] Jahoor | Protein-deficient pigs cannot maintain reduced glutathione homeostasis when subjected to the stress of inflammation[END_REF] . In neonatal pigs, cysteine and methionine deficiencies reduced cellular cysteine and GSH concentrations and increased oxidant stress in the small intestine which is associated with reduced small intestinal growth [START_REF] Bauchart-Thevret | Sulfur amino acid deficiency upregulates intestinal methionine cycle activity and suppresses epithelial growth in neonatal pigs[END_REF] . Threonine is the most abundant essential AA in glycoproteins like immunoglobulins and intestinal mucins [START_REF] Mantle | Isolation and characterization of the native glycoprotein from pig small-intestinal mucus[END_REF] . Growing pigs [START_REF] Defa | Effects of dietary threonine on performance, plasma parameters and immune function of growing pigs[END_REF] and gestating sows [START_REF] Cuaron | Effect of lysine and threonine supplementation of sorghum gestation diets on nitrogen balance and plasma constituents in first-litter gilts[END_REF] fed threonine-deficient diets have significant lower plasma concentrations of total or specific IgG titre following bovine serum albumin injection and swine fever vaccination. In piglets, threonine deficiency impaired total protein and mucin synthesis [START_REF] Wang | A deficiency or excess of dietary threonine reduces protein synthesis in jejunum and skeletal muscle of young pigs[END_REF] and impacted also on other functions of the small intestine [START_REF] Hamard | A moderate threonine deficiency affects gene expression profile, paracellular permeability and glucose absorption capacity in the ileum of piglets[END_REF] . Increased tryptophan catabolism and IDO activation during inflammation are considered as mechanisms involved in the regulation of immune and inflammatory response [START_REF] Floc | Tryptophan metabolism, from nutrition to potential therapeutic applications[END_REF] . Pigs suffering from an experimentally induced lung inflammation and fed a diet with tryptophan concentration slightly above recommendations had lower APP concentration, indicating that inflammation was reduced, and were healthier compared to pigs fed a diet moderately deficient in tryptophan [START_REF] Floc | Dietary tryptophan helps to preserve tryptophan homeostasis in pigs suffering from lung inflammation[END_REF] . In a porcine model of induced colitis, tryptophan supplementation down-regulated inflammation, restored local immune response and reduced colitis symptoms [START_REF] Kim | L-Tryptophan exhibits therapeutic function in a porcine model of dextran sodium sulfate (DSS)-induced colitis[END_REF] .

3/ Which consequences on swine nutrition

There is a growing interest in considering the specific AA requirement for preserving both health and performance. Basically, nutritional recommendations for growing pigs are still mainly established according to the maximization of performance criteria. All these criteria correspond to productive traits and are mainly associated to maximizing protein deposition during post-natal growth [START_REF]Nutrient Requirements of Swine, 10[END_REF] . This approach is consistent with the fact that AA are largely used for the synthesis of peptides and proteins, and that daily whole body protein turn-over requires huge amounts of AA [START_REF] Lobley | Protein turnover -what does it mean for animal production?[END_REF] ; in fact, this is true only for the 20 AA constituting proteins. To determine AA requirement for health maintenance, indicators of health status are needed. Indeed, if good growth performance is usually associated to good health, this criterion does not reflect necessarily physiological or nutritional status that could predispose the animal to disease and make him less resilient.

The necessity to reduce the dietary crude protein content to cope with environmental issues should increase the risk that several AA are supplied in inadequate or sub-limiting amounts for their physiological functions, some of them being not directly associated with productive traits. As previously underlined in the description of partitioning of scarce resources theory (see table 1), the question is which type of functions will have a priority for AA utilization. This is an important question considering that AA can be supplied at a suboptimal level for economic reasons. Another factor to take in account is the effect of health and sanitary conditions on feed intake. Indeed, depressed feed intake will limit the availability of AA for the body and this is probably the main limiting factor for developing nutritional strategies for preserving health and performance.

Few studies aimed to evaluate the impact of health status on the AA requirement for growth performance in pigs. All these studies clearly confirmed the negative impact of the health status on performance and feed intake. Pigs kept in an environment with a low sanitary status required less lysine for protein accretion because of their lower growth rate [START_REF] Williams | Effect of level of chronic immune system activation on the growth and dietary lysine needs of pigs fed from 6 to 112 kg[END_REF] . This occurred without change in efficiency of lysine utilization for protein deposition [START_REF] Williams | Effect of chronic immune system activation on the rate, efficiency, and composition of growth and lysine needs of pigs fed from 6 to 27 kg[END_REF] . Indeed, lysine has little physiological functions other than being incorporated in proteins. This explained that its requirement is mainly associated to growth and protein deposition. This result has been reported in poultry and confirmed for other AA such as threonine and arginine [START_REF] Webel | Lipopolysaccharide-induced reductions in food intake do not decrease the efficiency of lysine and threonine utilization for protein accretion in chickens[END_REF][START_REF] Webel | Lipopolysaccharide-induced reductions in body weight gain and feed intake do not reduce the efficiency of arginine utilization for whole-body protein accretion in the chick[END_REF] . Health status has an impact on tryptophan metabolism and this probably impairs the availability of tryptophan for body protein deposition and growth. Additional crystalline tryptophan did not totally prevent growth retardation caused by low sanitary status. However, the improvement of growth rate by supplementary tryptophan added to a low tryptophan diet was greater than for pigs with a good sanitary status, but maximum growth rate was obtained for the same tryptophan level in both sanitary statuses [START_REF] Floc | A moderate inflammation caused by the deterioration of housing conditions modifies Trp metabolism but not Trp requirement for growth of post-weaned piglets[END_REF] . Recently, a series of experiments examined the impact of immune system stimulation on sulfur AA, methionine and cysteine, metabolism and requirement for growth and protein deposition. Using a model of repeated injections of LPS in growing pigs, it was shown that LPS challenge did not influence nutrient digestibility and reduced the nitrogen balance. However, sulfur retention increased indicating a partitioning of sulfur AA in favor of non-protein body stores, i.e. glutathione and taurine [START_REF] Rakhshandeh | Immune system stimulation of growing pigs does not alter apparent ileal amino acid digestibility but reduces the ratio between whole body nitrogen and sulfur retention[END_REF] . This partitioning is probably the reason why pigs required more sulfur AA for maximizing protein accretion when submitted to repeated injection of LPS [START_REF] Litvak | Optimal dietary methionine to methionine plus cysteine ratio is increased during immune system stimulation in growing pigs[END_REF] . Antimicrobial growth promoters (AGP) were classically incorporated in feed to enhance performance. They act in preventing the development of bacteria in the gastrointestinal tract and maintaining the sanitary status of the animals. A series of experiments evaluated the impact of AGP removal on performance and AA requirement in pigs. Withdrawal of AGP increased threonine requirement to reach a maximum growth rate (84) . This could originate from an increased utilization threonine by the gut and/or the microflora.

Conclusion

The changes in protein and AA metabolism occurring when health status decline probably influence AA requirements. Additionally, specific AA can either enhance or inhibit body defenses. What is expected is that AA that have a direct effect on body defenses will have their requirement increased whereas decreased requirement is expected for AA involved in "production functions". The question is whether and how dietary AA supplies could be adapted to preserve both health and performance. Indeed, the physiological and metabolic status of an animal will be different if it is in good health or not. Moreover, health cannot be considered as a steady state but rather as a dynamic process resulting from the adaptation of the animal to their environment. As a consequence, the best strategy to adapt nutrition to health status is quite complex to define. A preventive strategy may lead to AA spoiling since additional AA will not be used by animals in good health. By contrast a curative solution may be inefficient since reduced feed intake caused by health deterioration will limit the availability of AA. The better strategy is likely to avoid situations of marginal AA deficiency. Marginal deficiencies may have no impact on productivity but may affect the animal ability to adapt to an immune challenge. Further investigations are required to improve our knowledge on AA metabolism and their implications in various physiological functions. One of the challenges in the future will be to identify novel traits and indicators that are modulated by the AA supply and that could be used to refine nutritional requirements and recommendations.

Figure 1 .

 1 Figure 1. Relationship between the change in growth (∆ADG) and feed intake (∆ADFI) of pigs challenged with digestive bacterial infections (a), poor housing conditions (b), LPS challenge (c), contaminations with mycotoxins (d), parasitic infections (e) and respiratory diseases (f).Responses are expressed as results of the challenged pigs relative to that of a control group. The lines represent the linear or the quadratic model adjustments. Estimated parameters differed from zero (P< 0.05), except for the intercept in LPS challenge From[START_REF] Pastorelli | Meta-analysis of feed intake and growth responses of growing pigs after a sanitary challenge[END_REF] .


Genotype x site interaction, climatic change and selection in Pinus pinaster : a new glance on old data

Annie Raffin (1,2) , Laurent Bouffier (1,2) (1) INRA, UMR1202 BIOGECO, F-33610 Cestas, France (2) Université de Bordeaux, UMR1202 BIOGECO, F-33610 Cestas, France Climatic change and Pinus pinaster breeding

Multisite evaluation

Eight progeny trials with 100 to 200 families and 3 sites per trial are currently being re-analysed. Genetic gains on dry sites will be compared for classical selection based on over-site breeding values and for selection based on dry site breeding values. Climatic change scenarios based on CO 2 elevation predict drier summers in western France, with a negative impact on forest productivity around the second half of this century (Loustau et al., 2005). Breeding strategies are to be refocused towards maintaining productivity on drier sites e.g. :

Prospects for the breeding program

Maritime pine in France: first planted species (900.000 ha). Analysis of GxE interactions can bring information on genotypes specifically adapted to dry sites, able to maintain an acceptable level of productivity with a low water availability in summer.

An example is given for one trial with 3 sites : dry, semi-humid and humid types; 196 progenies (196 ♀ trees x polymix1 of 42 ♂ or polymix2 of 43 ♂) are tested with 35 reps of 1tree-plots per site. Each tree was measured for circumference at 1.30m (cir08), total height (ht08) and stem straightness (ev08: deviation to verticality in cm at 1.50m) at age 8. Linear mixed models were used for statistical analysis, using ASReml v3.00 (VSNi) software.

Across site analysis was performed on spatially adjusted data using 2 different models :

(1) overall mean and site as fixed, site.family as random, with additive and error variances modelled for each site (2) overall mean and site as fixed, family as random

• extension of breeding zones to drier sites, • shortening selection cycle through forward instead of backward selection based on accurate bv estimates,

• accelerating seed orchard renewal to follow climate evolution,

• infusing new diversity with southern provenances, • selecting for adaptive traits for drought tolerance (water use efficiency, dendroplasticity),

• integrating phenotypic and genomic data to improve selection efficiency.

• using multi-site data and re-analysing GxE interactions is also a possibility to give a new insight on genotypes adaptation to dry sites.

Such genotypes may carry a different set of alleles for traits involved in growth on dry sites, compared to those that perform best over all types of sites. Using assortative mating between those tolerant genotypes could improve genetic gain for future climatic conditions.

Overall, there are few changes of ranking over sites. But some good across-site families perform poorly on the dry site; whereas some of the top 20 families on the dry site will not be selected based on across-site performance. For a growth index (equivalent weights on cir08 and ht08) the top 20 families classically selected on across-site performance will give 10% less genetic gain on the dry site, compared to the top 20 families specifically selected on dry-site performance.

References-

  Loustau, D. et al. Modeling climate change effects on the potential production of French plains forests at the sub-regional level. Tree Physiology 25, 313-323 (2005).

Figure 1 :

 1 Figure1: Standardized BV for A: cir08 and B:ht08 : across-site (model 2) and on each site (model 1), for the top 20 families selected on BV across-site (in grey and red lines) and for 3 additional families (in green lines) selected in top 20 on the dry site.

  Site Wet Site Across-site

Table 1 :

 1 Mean (mm, cm, and cm respectively) and standard error per site, and between site genetic correlations for cir08 (1 st line), ht08 (2 nd ) and ev08 (3 rd ).

			A
	Dry Site	Meso Site Wet Site
	Mean (se) 30.2 (0.1)	32.9 (0.1)	40.9 (0.1)
	540.8 (1.1)	642.7 (1.3)	730.5 (1.3)
	10.2 (0.2)	15.1 (0.3)	21.7 (0.4)
	Dry Site	0.45	0.65
		0.50	0.69
		0.91	0.84
	Meso Site		0.67
			0.64
			0.94


Role of the PAB

Involved in the ripenning of the swiss type cheeses Growth in warm curing room Cell density : 10 3 to 10 6 at 24H 10 9 in warm curing room 5 10 9 in warm curing room Eye formation in some swiss type cheese: release of C0 2

Resist to lysozyme Some strains produce highly heat-stable toxins.

Bacterial Biodiversity and In Situ Interactions Some strains produce highly heat-stable toxins.

Humans and animals are the primary reservoirs (nasal passages and throats and on the hair and skin of 50 percent or more of healthy individuals).

P. freudenreichii

To understand the mechanisms leading to biodiversity in two species:

-Host adaptation and virulence (S. aureus) -Ripenning and probiotic capabilities (P. freudenreichii).

Our goals

Bacterial Biodiversity and In Situ Interactions 11

To understand in situ interactions, cheese matrix or with the host (Digestive tract or mammary gland).

To control the expression of these bacterial potentials (technological, probiotic or pathogenic) in situ

  In 1878, first observation by Koch In 1880, Staphylococcus is recognized as a genus by Pasteur In 1884, Rosenberg cultures the first Staphylococci on solid medium Spherical bacterium (coccus). Gram-positive. Grape-like clusters. Catalase+ Facultative anaerobe. Growth in a wide range of temperatures (18-40°C) and salt concentrations (10% NaCl).

  de surface de L. delbrueckii et P. freudenreichii dans la modulation de l'inflammation intestinale Démonstration in vitro et in vivo de la capacité anti-inflammatoire. Origine de la souche-dépendance, lien avec les propriétés de surface.

freudenreichii P. freudenreichii, lipolysis and ripenning Lipolysis: essential role in the development of cheese flavor In emmental (swiss-type cheese), P. freudenreichii responsible for > 95% lipolysis Huge amount of cheese France: 1 st emmental producer worldwide, 250 000 t/year and 13.5% of the total cow milk production Lipolysis level is strain-dependant

	S. aureus	Animal Health	Food Safety
		Mastitis	SFP Outbreaks
			Human Health
		Cheese technology
		Ripenning
		Bacterial Biodiversity and In Situ Interactions	14

Probiotics

P.

Bacterial Biodiversity and In Situ Interactions 15 Our input:

Knowledge and access to high biodiversity / CIRM Integrated appraoch from gene to cheese Lipolysis level is strain-dependant To identify the molecular bases of the biodiversity to enhance criteria for starter selection

	S
	T1 T2 T3 T6 T8 T9 iT2
	iT6
		m g/g fat
		16
		14
		12
		10
		8
		6
	Substrat : 1-naphthyl	2 4
	propionate	0	pf279 pf279	ctrl	ctrl
		pf279: overexpressing pf279
		ctrl: controls (

transformed strains with the empty vector) WT: wild type strain C AEM, 2010. Analyse in silico : 12 candidats estérases 10 cytoplasmiques 1 sécrétée 1 ancrée Mic.Cell Fact., 2009. IJFM, 2011.

Bacterial Biodiversity and In Situ Interactions 16 D2R Origine

de la souche-dépendance du caractère lipolytique. Suivi de l'expression (ciblée et globale) pendant l'affinage. AEM, 2010. Identification d'une estérase sécrétée

	S. aureus	Animal health	Food Safety
		Mastitis	SFP Outbreaks
		Potentiel probiotique de P. freudenreichii
			Human Health
		Cheese technology
		Ripenning
		Bacterial Biodiversity and In Situ Interactions	17

Probiotics

P.

freudenreichii Potentiel probiotique de P. freudenreichii Probiotics to limit some pathologies: digestives tract diseases or immunological disorders (allergy, MICI)

	Dairy PAB have unic capabilities:
	modulation of the host microbiota (bifidogenic)
	hardiness
	apoptosis induction (pre-cancer cells)
	modulation of immune response
	Bacterial Biodiversity and In Situ Interactions	18

Highlights Perspectives

Bacterial Biodiversity and In Situ Interactions

Réponse des cellules de l'hôte à l'interaction avec S. aureus

Animal Health

Mastitis

Food Safety

SFP Outbreaks

S. aureus

Interactions between S. aureus and positive microbiota

Bacterial Biodiversity and In Situ Interactions

Host response

(well-being/ prevention)


Antoine Danquechin Dorval

Céline Meredieu

Sébastien Cavaignac

Frédéric Danjon

3rd International Congress on Planted Forests Influence of reafforestation techniques on architectural development of the root system and on toppling in Pinus pinaster saplings Funded by CDC and DIADEME region Aquitaine in Pinus pinaster saplings Bordeaux 16/05/2013

Wind resistance

Development of maritime pine root system

 Danjon & Fourcaud, 2009;Danjon & Reubens, 2008Adult tree "guyed cage"

Sapling

No retarded branching

Development of maritime pine root system

Better root distribution

Adult tree

If the circular distribution of the roots of the sapling is not homogeneous, the cage will be incomplete

Stable Unstable

Evolution of silvicultural practices Undamaged pines have a bigger and deeper taproot and also a larger volume of roots, leeward and windward.

Windward Leeward

Wind

What are the differences in root development between different toppling levels?

How does the establishment (seeded or planted trees) influences the development of the maritime pine root system? There are more undamaged trees on "planted, full ploughing" stand than on "planted, rotary ploughing" and "planted, strip ploughing" stands

There are more toppled trees on the "planted, full ploughing" stand than on "seeded, full ploughing" stand.

Discussions

Only few differences between the 3 tillages

  photo P. Alazard

  root system of trees from different tillagesTrees of rotary ploughing stand have a bigger taproot better planting bed ?


Matieu Henry

Laurent Saint-André

published or not. The documents may come

Graphical analysis and first data interpretation

  Dr. Matieu Henry & Dr. Laurent Saint-André, & Dr. Nicolas Picard Hanoi, June 18 -22 th 2012 (a) Linear relation and constant variance of the residue, (b) Non linear relation and constant variance (c) Linear relation and non constant variance of the residue (d) Non linear relations and non-constant variance of the residue Different relations between two variables X and Y Coefficients of determination (R2) for four linear regressions developed on cloud of points which do not have linear relations The coefficient of determination R 2 is used in the context of statistical models whose main purpose is the prediction of future outcomes on the basis of other related information. It is the proportion of variability in a data set that is accounted for by the statistical model When you have more than one input variables (X1, X2..)


Geniaux

In search of w for the spatial lag model

Plan

Introduction SLM with unknow W

A GNR for the SLM IV estimates MC Settings

MC Results

Conclusion

Geniaux

In search of W for the spatial lag model

Introduction

The spatial econometrics literature points out the importance of W choice but "tells us little about adequate foundations for these choices" [START_REF] Harris | In search of 'w[END_REF] The choice of W that corresponds to the true data generating process is crucial for the consistency of parameter estimates [START_REF] Bhattacharjee | Estimation of spatial weights matrix in a spatial error model, with an application to diffusion in housing demand[END_REF] of Spatial Lag Model (SLM).

Geniaux

In search of W for the spatial lag model Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings

MC Results Conclusion

How econometricians can choose W ?

A second approach starts with an unspecified spatial weight matrix and try to estimate a spatial weights matrices that are consistent with an observed pattern of spatial dependence. [START_REF] Conley | Gmm estimation with cross sectional dependence[END_REF][START_REF] Pinkse | Spatial price competition: a semiparametric approach[END_REF][START_REF] Meen | Spatial aggregation, spatial dependence and predictability in the uk housing market[END_REF][START_REF] Bhattacharjee | Estimation of spatial weights matrix in a spatial error model, with an application to diffusion in housing demand[END_REF] Geniaux In search of W for the spatial lag model Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings MC Results Conclusion

Aim of the paper

We propose in this article a parametric approach to estimate matrix W for SLM model at the frontier of the two first approaches discussed above.

The estimation procedure uses a (differentiable) flexible distance kernel with two parameters (the bandwidth h and the sharpness of weight decreasing around bandwidth k) to identify the matrix W .

Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings MC Results Conclusion

SLM with unknow W

We consider a spatial lag model [START_REF] Anselin | Estimation methods for spatial autoregressive structures: A study in spatial econometrics[END_REF][START_REF] Anselin | Spatial econometrics : Methods and Models[END_REF] with a weighting scheme based on distance that could be written in matrix form as:

Y = λW (h, k)Y + X β + (1)

IV estimates of SLM

Suppose first that h is known:

W (h) = W . Let us denote θ = [λ, β] ∈ Θ, where Θ is the parameter open space.
IV estimation provides a consistent estimator of θ using

Z ∈ X , WX , W 2 X , W 3 X ]. Let note Q = [WY , X ],
and

Q = P Z Q = [P Z X , P Z WY ],
where P Z = Z (Z Z ) -1 Z then we can rewrite the model (1) as:

Y = Qθ + (2)

Geniaux

In search of W for the spatial lag model

Assumptions

If we use a wrong h 0 = h and/or k 0 = k to estimate θ iv , then θ iv will be biased.

We could define SSR iv (h, k) = (h, k) (h, k) the function that gives the sum of square of residuals of regression (2) for a given couple (h, k).

We do a conjecture that the minimization of SSR iv (h, k) will provide the true (h,k) and a consistent estimate of θ iv .

Geniaux

In search of W for the spatial lag model Introduction SLM with unknow W A GNR for the SLM IV estimates

MC Settings MC Results Conclusion

A GNR for the SLM IV estimates

Following [START_REF] Davidson | Estimation and inference in econometrics[END_REF], a GNR for such non linear regression can be defined as:

Y -H( θiv ( ĥ)) = ∂H ∂h ĥb + (4)
Then:

∂H ∂h ĥ = θh iv P Ẑ Q + θiv P h Ẑ Q + θiv P Ẑ Q h Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings MC Results

Conclusion

Gradients definition

θh iv = ( Q P Ẑ Q) -1 -( Q h P Ẑ Q + Q P h Ẑ Q + Q P Ẑ Qh )( Q P Ẑ Q) -1 Q P Ẑ y +( Q h P Ẑ + Q P h Ẑ )y Qh = [0 . . . Ŵ h Y ] Ŵ h ij = 2 ĥ3 e -(D ij / ĥ) 2 k e -(D ik / ĥ) 2 l D 2 ij -D 2 il e -(D il / ĥ) 2 k e -(D il / ĥ) 2 = 2W ij h 3 D 2 ij - j D 2 ij W ij P h Ẑ = Ẑ h ( Ẑ Ẑ ) -1 Ẑ + Ẑ ( Ẑ Ẑ ) -1 Ẑ h -Ẑ ( Ẑ Ẑ ) -1 ( Ẑ h Ẑ + Ẑ Ẑ h )( Ẑ Ẑ ) -1 Ẑ Ẑ h = 0 . . . W h X . . . ( Ŵ h Ŵ + Ŵ Ŵ h )X Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings

MC Results Conclusion

Gradients definition -general case

Y -H( θiv ( ĥ, k)) = ∂H ∂h ĥ, k b h + ∂H ∂k ĥ, k b h +
Where superscript h (resp. k) indicates a derivative with respect to h (resp. k): h=0.015, k=2

W h ij = kW ij h k+1 D k ij - j D k ij W ij W k ij = -W ij ln(D ij /h)(D ij /h) k - j ln(D ij /h)(D ij /h) k W ij Geniaux In
q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q Geniaux In search of W for the spatial lag model

Exploring SSR iv (h, k) h=0.03, k=3 q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q 0.01 0.02 0.03 0.04 0.05 0.06

Conclusion

When the type of weighting scheme is unknown, the procedure proposed in our last MC experiments highlights very promising results.

For large datasets, the use of gradients (GNR) must be limited to cases where the spatial autocorrelation is high (λ >= 0.3) and with a convenient number of mean neighbors (h not to large).

Geniaux

In search of W for the spatial lag model

Demonstrate the consistency of the estimator will be a priority of our future works.

Geniaux

In search of W for the spatial lag model

  W for the spatial lag model MC Results for k known and wt = EDK Geniaux In search of W for the spatial lag model Results for k unknown and wt = EDK Geniaux In search of W for the spatial lag model Introduction SLM with unknow W A GNR for the SLM IV estimates MC Settings MC Results Conclusion Results k and wt unknown n = 1000, r = 300, β = (1, 0.5) wt=randomly (EDK , DBAR, KNEAR) l = random, k =randomly (2, 3, 12) h λ TRUE wt freq % good pred.

Neighbors of i for distance d<0.08

						Introduction
				SLM with unknow W
	A GNR for the SLM IV estimates
						MC Settings
						MC Results
						Conclusion
	MC Settings
	1.0
	0.8
	0.6
	0.4
	0.2
	0.0
	0.8
	0.6					0.8
	y	0.4	0.2	0.2	0.4	0.6 x
						search of W for the spatial lag model

wi Exponential Distance Kernel Weight wi=EDK(D,h=0.08,k=2)

	MC Settings
			0.04
			0.03
		wi	0.02
			0.01
			0.00
			0.8
			0.6				0.8
			y	0.4	0.2	0.2	0.4	0.6 x
	Geniaux	In search of W for the spatial lag model

Distance Band Binary Weight wi=DBAR(D,h=0.08)

						K-
	0.05
	0.04
	0.03
	wi
	0.02
	0.01
	0.00
	0.8
	0.6					0.8
	y	0.4	0.2	0.2	0.4	0.6 x

nearest neighbors weight wi=KNEAR(D,k=10)

		Introduction Introduction
	SLM with unknow W SLM with unknow W
	A GNR for the SLM IV estimates A GNR for the SLM IV estimates
		MC Settings MC Settings
		MC Results MC Results
		Conclusion Conclusion
	MC Settings Exploring SSR iv (h, k)
		16
	Surface plot of	14								1.08
	3 λ ∈ (0.2, 0.4, 0.6). SSR iv (h, k) for	12		0.10					1.07
	4 h ∈ (0.008, 0.015, 0.03) for all wt. 5 k ∈ (2, 3, 12) for wt = EDK λ = 0.2, k = 2 and h = 0.015. We use 6 a 100 x 100 grid 8 10 k	wi	0.00 0.02 0.04 0.06 0.08					1.05 1.06	SSR(Beta_iv(h,k))
	with h ∈ [0.002, 0.1]	4			0.8	0.6 y	0.4	0.2	0.2	0.4	0.6 x 1.04 0.8
	and k ∈ [1, 16].	2								1.03
		0.01	0.02	0.03	0.04		0.05	0.06
				h
		Geniaux Geniaux	In search of W for the spatial lag model In search of W for the spatial lag model

Conclusion

The properties of the estimator in finite sample estimator appear satisfactory. When the type of weighting scheme is known (gaussian, tri-cube, distance band or others distance based weight matrices), the minimizing algorithm allows a good approximation of the bandwidth, and easy to use for moderate sample size.

Geniaux

In search of W for the spatial lag model