Éditeur(s) : University of Suriname Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : Tomato is one of the most popular vegetables in the world. Therefore, for improvement in crop productivity in Suriname and most other countries, excessive application of pesticides and synthetic fertilizers is used. These result in gradual depletion of soil fertility and microbial diversity. Conventionally managed soils are found to exhibit a poorer micro flora and a lower biological activity then organically managed soils. Recently much attention is paid to organic cultivation and the use of bio fertilizers as a supplement for chemical fertilizers. VAM fungi have the potential to improve the sustainability of tomato production by improving yield and quality. Therefore, the aim of the study was to evaluate the effect of two different concentrations of commercially available vesicular - arbuscular mycorrhiza on the plant growth and fruit production of two tomato varieties (Lycopersicon esculentum Mill.) in the greenhouse.The experiment was set up as a randomized factorial block design with two independent factors and consisted of six treatments and three replications. The factors were two tomato varieties: hybrid 61 and hybrid 501 and two concentrations of VAM namely 2.5 and 10 g. VAM/plant. Biomass was determined two times, at bloom initiation and at the end of the experiment. The growth parameters were measured once per week. The production was recorded only for the first two harvest times. Data was statistically analyzed using three-way ANOVA. The results of this experiment showed that the VAM fungi had a positive influence (p < 0.05) on the production for both varieties of tomatoes. And it also resulted in earlier reproduction. There was no significant difference in production (p > 0.05) between the two concentrations of VAM inoculum used.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16303
V16303

Éditeur(s) : Elsevier
Résumé : The New Caledonia blue shrimp Litopenaeus stylirostris is commercially produced under semi-intensive rearing conditions. The size of the farming earthen ponds (5–10 ha) and the subsequent production constraints make it difficult to use them as experimental units for random experiments. Moreover, since every pond has its own characteristics, ponds' effects cannot be ruled out, thus making it hard to define true replicates. In order to design future experiments under conditions resembling those used in production, we evaluated the possible use of floating cages as experimental units with the aim of assessing treatment effects with a reasonable statistical power. To this end, two sets of floating cages were placed respectively in two different ponds in a commercial farm. In both cases the zootechnical conditions in the cages were similar in post-larvae origin, management, and diet and feeding regime. The aim of the study was to evaluate on a technical basis the possibility of rearing shrimps in floating cages set up in earthen ponds and to assess this method from a statistical standpoint. Shrimps reared in and outside the cages showed comparable growth and survival rates. The variability in the zootechnical parameters between cages, expressed as the estimated coefficient of variation (CV) for survival rate, total final biomass (g), final body weight (g), daily increment in body weight (g day− 1) and FCR were 11.0, 13.7, 4.4, 5.4, and 7.0%, respectively. On the basis of these figures, we calculated for a given statistical power (80%) the number of replicates (cages) that would be required to reveal significant differences between two treatments, at a 5% level of significance. We found that for expected differences of 20% from the control mean, 3 and 6 floating cages per treatment would be reasonable to determine statistical differences for growth parameters and survival rate, respectively. Moreover, we showed a significant pond effect in regard to survival and growth between the two sets of cages. These results illustrated the within-farm variability among the ponds, and confirmed that the specific characteristics of each pond from the same farm make it difficult to use the ponds themselves as experimental units. The study demonstrates that rearing in floating cages is an economical, powerful and sensitive experimental tool for shrimp culture studies specifically carried out under conditions close to semi-intensive production.
Aquaculture (0044-8486) (Elsevier), 2008-07 , Vol. 279 , N. 1-4 , P. 63-69

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4363.pdf
DOI:10.1016/j.aquaculture.2008.03.053
http://archimer.ifremer.fr/doc/00000/4363/

Éditeur(s) : Caribbean Agricultural Research and Development Institute Caribbean Agricultural Research and Development Institute ( Saint Lucia )
Résumé : (Bibliography) Bibliography: p. 87.
(Statement of Responsibility) John L. Hammerton and F.B. Lauckner.
Includes index.
"An output of the CARDI/USAID FSR/D Project #538-0099."
"April 1984."
(Funding) Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
Caribbean Area
Caribbean Area
Caribbean Area

002199173
13983256
ALD9055

Éditeur(s) : University of Florida, Agricultural Experiment Station University of Florida, Agricultural Experiment Station ( Gainesville, Fla. )
Résumé : (Statement of Responsibility) A.J. Norden, H.A.D. Chesney, A.P. Stephenson.
(Internal Comments) A.J. Norden, H.A.D. Chesney, A.P. Stephenson.
Cover title.
January 1972.
University of Florida Agricultural Experiment Station circular S-215
Guyana
Guyana

23904063

Éditeur(s) : College of the Virgin Islands College of the Virgin Islands ( St. Croix?, St. Croix? )
Résumé : (Statement of Responsibility) Agricultural Experiment Station and Cooperative Extension Service.
(Dates or Sequential Designation) 1981-1982-
Title from cover.
United States Virgin Islands
Virgin Islands of the United States
Virgin Islands of the United States

13506492
88646613

Résumé : Additional label information: branch with fruit. Summit, Canal Zone. USDA - Foreign Agric'l Relations Photo
Additional label information: Trees nineteen years old. Summit, Canal Zone. Cassia javanica
North America -- Panama -- Caribbean
Caribbean
Caribbean area
Panama

C.Z. 83

North America -- Panama -- Caribbean
Caribbean
Canal Zone
Caribbean
Panama
Panama

C. Z. 80

Éditeur(s) : HAL CCSD
Résumé : International audience
STUDY QUESTION: Do freezing and in vitro culture procedures enhance the expression of proteins involved in apoptotic or autophagic pathways in murine pre-pubertal testicular tissue? SUMMARY ANSWER: IVM strongly modified apoptosis- and autophagy-related relative protein levels in mice testicular tissue whereas the impact of cryopreservation procedures was minimal at the end of the culture. WHAT IS KNOWN ALREADY: In vitro spermatogenesis remains a challenging technical issue as it imposes to find a very close balance between survival and death of germ cell natural precursors (i.e. gonocytes and spermatogonia), which will eventually undergo a complete spermatogenesis close to in vivo conditions. The establishment of efficient culture conditions coupled with suitable cryopreservation procedures (e.g. controlled slow freezing [CSF] and solid surface vitrification [SSV]) of pre-pubertal testicular tissue is a crucial step in the fields of fertility preservation and restoration to improve the spermatic yield obtained in vitro. STUDY DESIGN, SIZE, DURATION: Here, we study cryopreservation procedures (i.e. CSF or SSV) and the impact of culture media compositions. A first set of 66 mouse pre-pubertal testes were directly cultured during 30, 36, 38 and 60 days (D) from 2.5 to 6.5-day-old CD-1 mice to evaluate the impact of time-aspect of culture and to endorse the reverse phase protein microarrays (RPPM) technique as an adapted experimental tool for the field of in vitro spermatogenesis. Ninety others fresh, slow-frozen and vitrified pre-pubertal testes were cultured during 30 days for the principal study to evaluate the impact of cryopreservation procedures before and after culture. Thirty-four testes dissected from 2.5, 6.5, 36.5, 40.5, 42.5 and 62.5 days postpartum (dpp) mice, corresponding to the time frames of spermatogenesis orchestrated in vitro, were used as in vivo controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: After in vitro culture, testicular tissue samples originated from 2.5 or 6.5-day-old CD-1 male mice were analyzed using RPPM. This targeted proteomic technique allowed us to assess the expression level of 29 apoptosis- and autophagy-related factors by normalizing blank-corrected signal values. In addition, morphological analyses (e.g. HES, PAS, TRA98 and CREM) and DNA fragmentation in intra-tubular cells (i.e. terminal deoxynucleotidyl transferase dUTP nick end labeling; TUNEL) were assessed for the distinct experimental conditions tested as well as for in vivo control mouse testes. MAIN RESULTS AND THE ROLE OF CHANCE: A validation of the RPPM procedure in the field of in vitro spermatogenesis was completed with assay and array robustness before a principal study concerning the evaluation of the impact of in vitro culture and cryopreservation procedures. The proportion of elongated spermatids and the total cell number per seminiferous tubule tended to be very different between the in vivo and in vitro conditions (P < 0.05), suggesting the presence of a beneficial regulation on the first spermatogenesis wave by intrinsic apoptosis (Caspase₉) and autophagy (Atg5) factors (P < 0.0003 and r2 = 0.74). Concerning the impact of culture media compositions, a basic medium (BM) composed of αMEM plus 10% KnockOut™ serum replacement and gentamicin supplemented with retinol (Rol) and vitamin E (Vit. E) was selected as the best culture medium for fresh 6.5 dpp tissue cultured during 30D with 27.7 ± 8.10% of seminiferous tubules containing elongated spermatids. Concerning the impact of cryopreservation procedures, SSV did not have any impact on the morphological parameters evaluated after culture in comparison to fresh tissue (FT) controls. The proportion of tubules with elongated spermatids on testicular explants cultured with BMRol+Vit. E was not different between SSV (6.6 ± 1.6%) and CSF (5.3 ± 1.9%); however, round spermatids were observed more frequently for SSV (19 ± 6.2%) than CSF (3.3 ± 1.9%, P = 0.0317). Even if the proportion of TUNEL-positive cells for BMRol+Vit. E was higher at D30 after SSV (4.12 ± 0.26%) than CSF (1.86 ± 0.12%, P = 0.0022) and FT (2.69 ± 0.33%, P = 0.0108), the DNA damages observed at the end of the culture (i.e. D30) were similar to respective 6.5 dpp controls. In addition, the relative protein level expression ratio of an apoptotic factor, the phosphorylated FADD on Fas, was reduced by 64-fold in vitrified testes cultured with BMRol+Vit. E. Furthermore, we found in this study that the StemPro®-34 SFM culture medium supplemented with growth factors (e.g. EGF, bFGF, GDNF and LIF) prevented the differentiation of spermatogonial stem cells in favor of a significant proliferation with a better architectural pattern than in vivo 6.5 dpp controls with an increase of seminiferous tubules area for FT (P = 0.0357) and CSF (P = 0.0317). LIMITATIONS REASONS FOR CAUTION: Despite our promising results, the evaluation of apoptotic- and autophagic-related proteins was studied for a limited amount of proteins and on global testicular tissue. WIDER IMPLICATIONS OF THE FINDINGS: The data presented herein will help to improve apoptotic and autophagic understanding during the first spermatogenic wave. Moreover, our findings illustrate for the first time that, using finely-tuned experimental conditions, a testicular in vitro culture combined with proteomic technologies may significantly facilitate the study of cryopreservation procedures and in vitro culture evaluations. This study may also contribute to improve work on testicular tissues from pre-pubertal and adolescent cancer survivors. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by a Ph.D. grant from the Rouen Normandie Université and a financial support from 'la Ligue nationale contre le cancer' (both awarded to L.D.), funding from Institute for Research and Innovation in Biomedicine (IRIB), Agence de la Biomédecine, and co-supported by European Union and Région Normandie. Europe gets involved in Normandie with European Regional Development Fund (ERDF). The authors declare that there is no conflict of interest.
Molecular Human Reproduction

hal-01647081
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647081
DOI : 10.1093/molehr/gax054
PUBMED : 29040674

Éditeur(s) : George A. Smathers Libraries, University of Florida University of the Virgin Islands George A. Smathers Libraries, University of Florida ( Gainesville, FL ) University of the Virgin Islands ( St. Thomas, US Virgin Islands )
Résumé : Grant proposal for Project Ceres Proposal, USAIN Digital Libraries & Preservation Committee (2014).

Droits : Applicable rights reserved.
http://ufdc.ufl.edu/AA00020002/00001

Éditeur(s) : Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida ( Gainesville )
Résumé : (Bibliography) Includes bibliographical references (p. 49-51).
(Statement of Responsibility) Mark A. Peters, Timothy G. Taylor.
"March 1990"--Cover.
(Funding) Bulletin (University of Florida. Agricultural Experiment Station) ;
Jamaica
Jamaica
Florida

22121459

Éditeur(s) : Dept. of Agriculture, Soil Conservation Service Dept. of Agriculture, Soil Conservation Service ( [Washington] )
Résumé : (Bibliography) Bibliography: p. 68.
(Statement of Responsibility) by Rafael A. Boccheciamp.
Prepared in cooperation with University of Puerto Rico, Agricultural Experiment Station.
Issued Nov. 1977.
Puerto Rico
San Juan

001198227
04617717
AFU8468

Éditeur(s) : University of the Virgin Islands Agricultural Experiment Station ( Saint Croix, U.S.V.I )
Résumé : (Bibliography) Includes bibliographical references (p. 22).
Cover title.
(Statement of Responsibility) Agricultural Experiment Station, University of the Virgin Islands.
United States Virgin Islands
Virgin Islands of the United States
Virgin Islands of the United States

35332558
http://ufdc.ufl.edu/UF00096194/00001

Éditeur(s) : Pêche thonière et dispositifs de concentration de poissons, Caribbean-Martinique, 15-19 Oct 1999
Résumé : Since the beginning of 1980, the Martinique fishermen have suffered a deep crisis. The traditional ways of fishing, based on benthic fish exploitation, have seen the decreasing of their profitability due to the over-fishing of the narrow continental shelf offering few resources. The pelagic fishery had become the professional main source of income. This fishery equally encounter difficulties: denied rights of access in the EEZ of Caribbean islands, expensive costs of exploitation. The disposal of FADs offers new ways to the Martinique fishermen. In 1999, it was decided the disposal of a onetworko of 30 permanent FADs around Martinique. The mooring of these FADs must be followed by legal and economic adapted measures to reach the desired aim: the development of local fishery economy through a sustainable fishing practice. Therefore, the French authorities have decided to make the regional fishermen committee responsible for the management of FADs.This committee is the only one to be entitled to moor and to deliver licences to FADs. This committee, gathering all the fishing industry representatives, has regarding the french law the right of mooring and delivering licences to the FADs access, collecting fishery statistics. These data should fund research to improve the management of the fishery, care and replace FADs. This programas realisation, as well as durability, need adequate financial planning. It has been included in the European commission financing program. This plans success will ensure the increase of the fishermen income, maintain and develop employment.Original Abstract: Apres une periode d'experimentation lancee localement au debut des annees quatre-vingt, les premiers resultats ont ete suffisamment probants pour conduire les professionnels a souhaiter l'implantation de dispositifs de concentration de poissons (dcp) en Martinique ou a les implanter eux-memes pour la capture des dorades coryphenes, des thons noirs, de l'albacore ou du listao. Le colloque international sur la peche thoniere et les dispositifs de concentration de poissons organise du 15 au 19 octobre 1999 en Martinique donne l'occasion de revenir sur le contexte, l'interet et les modalites de developpement de la technique des dcp en Martinique.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00042/15305/12639.pdf
http://archimer.ifremer.fr/doc/00042/15305/

Éditeur(s) : University of Florida. University of Florida. ( Gainesville )
Résumé : (Dates or Sequential Designation) 1st- 1931-
Manuscript copy of Proceedings of the 1st Meeting.

01411295
ocm01411295

Éditeur(s) : Poster présenté au colloque Carribean & Latin American Aquaculture 2007, 6 - 9 novembre 2007, San Juan, Puerto Rico
Résumé : The first aim of this study was to evaluate on a technical basis the rearing of shrimps in floating cages set up in earthen ponds. Shrimps reared in and outside the cages presented comparable growths and survival rates. Then it was concluded that shrimp culture in floating cages did not present zootechnical biases comparing to pond culture. The second objective of this study was to assess the present method as a statistical point of view. We found that for expected differences of 20% to the control mean, 3 and 6 floating cages per treatment will be reasonable to determined statistical differences for growth parameters and survival. Furthermore, we showed a significant pond effect as regard as survival and growth between both sets of cages. This results illustrated the within farm variability among the ponds, and confirmed that specific characteristics of each ponds from a same farm make difficult to use them as experimental unit. The study demonstrates that floating cages rearing is an economical, powerful, and sensitive experimental tool for shrimp culture studies specifically undertaken under close to semi-intensive production conditions.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/acte-4100.pdf
http://archimer.ifremer.fr/doc/00000/4100/

Éditeur(s) : Elsevier
Résumé : The effect of ambient ammonia, hypoxia and combination of both on survival and the physiological and immunological response of the blue shrimp Litopenaeus stylirostris in relation to molt stage was studied. Shrimp were submitted to 44.0-71.5 mg 1(-1) total ammonia-N corresponding to 2.0 mg 1(-1) unionized ammonia NH3-N and/or to 1.5 mg O-2 1(-1) (4.3 kPa) for 24 hours. Survival was recorded and the molt stages of both dead and surviving shrimp determined. Only shrimp in intermolt and premolt stages were sampled for analysis of haemolymph. Haemolymph was assayed for osmoregulatory capacity (OC), magnesium ion (Mg2+), calcium ion (Ca2+), total proteins, oxyhaemocyanin, lactate, glucose and total haemocyte count (THC). Low mortalities were recorded for shrimp submitted independently to ammonia or hypoxia. Seventy five percent of dead shrimp were in early post molt (stage A) in ammonia treatment, while hypoxia affected mainly late premolt animals (stage D-2). A synergic effect of ammonia and hypoxia combination (A+ O-2 treatment) on mortality was observed, affecting nearly exclusively shrimp in late premolt stage D-2. Analysis of molt stage repartition at the end of the experiment suggests that ammonia treatment may have accelerated molting. The common physiological response of shrimp to the different treatments was characterized by a reduced OC and an increase in Ca2+. Increase in Mg2+ could not be validated by the statistical analysis, as well as glycaemia variations. Plasmatic lactate level increased and THC decreased in shrimp submitted to hypoxia and the combination of hypoxia and ammonia. Total proteins concentration was reduced in ammonia and A+O-2 treatments. The effect was more pronounced in late premolt shrimp than in intermolt shrimp. Combination of ammonia and hypoxia led to a physiological response stronger than this observed for ammonia-alone and/or hypoxia-alone treatments, except for oxyhaemocyanin. The effects of each external factor (ammonia, hypoxia) and the combination of both, and internal one (molt stage) are discussed. (c) 2007 Elsevier B.V All rights reserved.
Aquaculture (0044-8486) (Elsevier), 2008-02 , Vol. 274 , N. 2-4 , P. 398-407

Droits : 2008 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2008/publication-4092.pdf
DOI:10.1016/j.aquaculture.2007.11.033
http://archimer.ifremer.fr/doc/00000/4092/

Résumé : La banane plantain (Musa paradisiaca) est l’aliment de base de millions de personnes dans le monde et sa culture génère des revenus permanents pour un grand nombre d’agriculteurs, dans des plantations de taille petite ou moyenne. Comme dans d’autres régions tropicales, la culture du plantain en Guadeloupe et en Haïti est soumise à de fortes contraintes parasitaires aussi bien telluriques (i.e. du sol : nématodes phytoparasites et charançon du bananier) qu’aériennes (Cercosporiose noire notamment). Les moyens de lutte conventionnels reposent sur l’usage de produits de synthèse dont les effets néfastes sur l’environnement (sols, eaux, animaux) comme sur la santé humaine ne sont plus supportables. Il est donc urgent de réfléchir à des solutions agro-écologiques permettant de rétablir les équilibres biologiques, de maintenir une bonne qualité des sols et une production optimale dans les systèmes de culture plantains. C’est le but de ce travail de thèse qui couple la réalisation d’un diagnostic agro-écologique dans des parcelles paysannes, et le test d’alternatives agro-écologiques en milieu semi-contrôlé. Pour ce faire, une typologie des systèmes de culture plantains a été réalisée à l’issue d’une enquête agro-environnementale dans les deux zones d’étude. Elle a permis de sélectionner 23 parcelles en Guadeloupe et 12 en Haïti dans lesquelles un diagnostic agro-écologique a été conduit. Sur la base de ce diagnostic et de la recherche d’alternatives agro-écologiques à l’usage des produits chimiques, une expérimentation au champ a été mise en place en Guadeloupe en station de recherche, permettant le test de trois pratiques culturales innovantes pour le plantain (seules et combinées), à savoir : i) l’introduction d’une plante de service Paspalum notatum pour la gestion des adventices et la réduction de l’utilisation d’herbicides ; ii) l’apport de vermicompost pour le contrôle des nématodes phytoparasites inféodés au bananier plantain et la fertilisation de celui-ci ; iii) l’utilisation de plants sains PIF (Plants Issus de Fragments de tiges) indemnes de nématodes et de larves de charançon du bananier. La typologie des systèmes de culture plantains révèle que : i) en Guadeloupe les précédents : jachère, ananas et banane plantain sont prédominants avec un niveau d’intensification faible (apports d’intrants chimiques faibles et peu fréquents) ou élevé (apports d’intrants chimiques élevés et plus fréquents) ; ii) en Haïti, les précédents : jachère, banane plantain et manioc prédominent avec un niveau d’intensification faible ou nul (apport d’intrants inexistant). Les résultats du diagnostic agro-écologique montrent que, i) lorsque le niveau d’intensification est faible, les bananeraies plantains pérennes et le précédent-ananas permettent de maintenir une bonne qualité du sol et une bonne régulation des parasites telluriques ; ii) lorsque le niveau d’intensification est fort, les populations d’ingénieurs du sol diminuent drastiquement, alors que le cortège parasitaire tellurique augmente sans que cela n’affecte l’obtention de bons niveaux de rendement instantannés (parcelles précédées d’ananas ou d’une jachère principalement) ; iii) en absence totale de fertilisation, il résulte une diminution de l’activité biologique du sol mais aussi du rendement du plantain, exacerbé par le choix des précédents-culturaux (manioc ou banane plantain) en lien avec les contraintes pédoclimatiques et la maladie des raies noires (Cercosporiose noire) causée par Mycosphaerella fijiensis, notamment au sein des parcelles Haïtiennes ; iv) la succession plantain/plantain est la plus pénalisante vis-à-vis de la culture du plantain, car quelque soit le niveau d’intensification, le rendement reste relativement faible, en lien avec une dégradation de l’état sanitaire, comparativement aux autres précédents.
Plantain (Musa paradisiaca) is the staple food of millions of people worldwide and its cropping generates ongoing revenues for many farmers who are planting small or medium size areas. As in other tropical regions, plantain cultivation in Guadeloupe and Haiti is under heavy parasitic constraints terrestrial (plant-parasitic nematodes and banana weevil) as well as aerial (black Sigatoka in particular). Conventional means of control based on the use of synthetic products which adverse effects on the environment (soil, water, animals ...) as on human health are not bearable any more. It is thus urgent to think about agroecological solutions allowing to restore the biological balances, to maintain good soil quality and optimal plantain cropping systems.This is the ultimate goal of this thesis which couples the realization of an agroecological diagnosis in peasants’ plots, and the test of agroecological alternatives in semi-controlled conditions. To do this, a typology of plantain cropping systems was carried out from an agrienvironmental survey in the two study areas. It allowed to select 23 plots in Guadeloupe and 12 in Haiti in which an agroecological diagnosis was implemented. Based on this diagnosis and the research of agroecological alternatives to the use of chemicals, a field experiment was set up in Guadeloupe, in an experimental station allowing the test of three innovative practices for plantain cultivation (alone and combined), namely : i) the introduction of a cover-crop Paspalum notatum for weed control while reducing the use of herbicides ; ii) the input of worms’ compost to control plant-parasitic nematodes specific to plantain and to fertilize it ; iii) the use of healthy “PIF” plants (plants issued from stem fragments) free from telluric pests (nematodes and weevil’s larvaes).The typology of plantains cropping systems shows: i) in Guadeloupe the previous crops are: fallow pineapple and plantain predominate with a low level of intensification (low and infrequent chemical inputs) or high (high and frequent chemical inputs); ii) in Haiti, the previous crops are: fallow, plantain and cassava predominate with a low level or no intensification at all (no inputs). The results of the agroecological analysis show that : i) when the level of intensification is low, perennial plantain and pineapple as previous crops help maintaining a good soil quality and a good regulation of the telluric pests ; ii) when the level of intensification is strong, the soil engineers drastically reduce, while the density of telluric parasites increases without affecting good levels of instantaneous yields (plots where the previous crop is pineapple or mostly fallow) ; iii) when the fertilization is totally missing, it decreases the biological activity of the soil furthermore the plantain yields, exacerbated by the choice of the previous crop (cassava or plantain), in connection with soils and climate constraints and the black Sigatoka caused by Mycosphaerella fijiensis, especially in the Haitian plots ; iv) the crop succession plantain/plantain is the most critical regarding the plantain’s cropping, because whatever the level of intensification, the yields remain relatively low in connection with a degradation of the health state, compared to other previous crops.The driving of an experiment in a research station shows that on the scale of one year, the three tested innovative practices allow maintaining a good soils quality. Healthy plants "PIF" have a better health state (absence of plant parasitic nematodes in the roots) which helps a significant increase of the yields. Cover-crop P. notatum helps the weeds and the soil pests control and favors the improvement of soil biological activity and plantain yields. Worms’ compost contributes to the maintenance of a better soils quality while allowing the regulation of the populations of plant-parasitic nematodes of the plantains.

http://www.theses.fr/2014AGUY0758/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Voting rules relying on k-nearest neighbors (k-NN) are an effective tool in countless many machine learning techniques. Thanks to its simplicity, k-NN classification is very attractive to practitioners, as it enables very good performances in several practical applications. However, it suffers from various drawbacks, like sensitivity to "noisy" instances and poor generalization properties when dealing with sparse high-dimensional data. In this paper, we tackle the k-NN classification problem at its core by providing a novel k-NN boosting approach. Namely, we propose a supervised learning algorithm, called Universal Nearest Neighbors (UNN), that induces a leveraged k-NN rule by globally minimizing a surrogate risk upper bounding the empirical misclassification rate over training data. Interestingly, this surrogate risk can be arbitrary chosen from a class of Bregman loss functions, including the familiar exponential, logistic and squared losses. Furthermore, we show that UNN allows to efficiently filter a dataset of instances by keeping only a small fraction of data. Experimental results on the synthetic Ripley's dataset show that such a filtering strategy is able to reject "noisy" examples, and yields a classification error close to the optimal Bayes error. Experiments on standard UCI datasets show significant improvements over the current state of the art.
ISSN: 0925-2312

hal-00664462
https://hal.inria.fr/hal-00664462

Éditeur(s) : HAL CCSD Editions Paralia CFL
Résumé : L'hydrodynamique du plateau continental du Golfe du Lion est généralement induite par les vents. Les simulations numériques réalisées par les modèles numériques de circulation océanique côtière aux équations primitives sont en général cohérentes avec les observations in-situ. Très peu d'observations étaient toutefois disponibles pendant les épisodes de tempêtes méditerranéennes. Aussi, la station BESSète (Bottom Experimental Station Sète), équipée d'un ADCP mesurant en continu les caractéristiques de houle et les profils verticaux de courants, a été implantée sur le plateau sous 70 m. Les premières données issues de cette station, acquises en février-mars 2007, confirment les schémas de circulations induits par les vents de Nord (Mistral,Tramontane). Un épisode de tempête (Hs>5m) a aussi pu être observé le 18 février 2007. De forts courants dont l'intensité peut atteindre 0,7 ms-1 y sont associés. Cette série de données est ensuite utilisée pour calculer les tensions decisaillements induites sur le fond. Sous 70 m, elles sont en général quasi-nulles excepté pendant l'épisode de tempête où l'action conjuguée des houles et des courants peut induire des contraintes susceptibles de mobiliser et déplacer le sédiment fin présent dans la zone. La très forte intensité des courants mesurés pendant la tempête amènent ensuite à reconsidérer les processus de transferts de quantité de mouvement entre atmosphère, océan et sédiments. Très schématiquement, sur le plateau, dès que la houle interagit avec le fond, la houle se transforme (réfraction, dissipation) et transmettrait de la quantité de mouvement à l'échelle des courants moyens. Cette hypothèse est retenue pour expliquer ces forts courants observés et pourrait être confirmée par d'autres travaux théoriques et numériques.
ISSN: 1760-8716

hal-00854000
https://hal.archives-ouvertes.fr/hal-00854000
DOI : 10.5150/jngcgc.2008.011-L

Résumé : Penaeus stylirostris shrimp imported from Hawaii for a genetic program and kept at the Saint-Vincent research facility had progressively developed a high sensitivity to IHHNV, the etiological agent of the Infectious, Hypodermic, and Hematopoietic Necrosis. Fears were that the virus could not only be transferred to their offspring, but also that the New Caledonian strain of Penaeus stylirostris, so far considered as resistant, could become sensitive by an off balance of its hosts/pathogen equilibrium. In October 2008, a joint decision between Uprac (shimp owner), Davar (New Caledonian Animal Health Authority) and Ifremer (scientific partner) was taken to terminate all pure breed and hybrid Hawaiian populations remaining in the ponds, and to implement an intensive fallowing protocol, and controlled restocking. IHHNV was also suspected to trouble experiments carried out in the research facility (mortalities, deformities, slow growth), thus affecting research programs. Difficulties pointed out by IHHNV have triggered since 2008 some awareness on biosecurity issues at some level of the New Caledonian shrimp industry. At the St-Vincent research station, it led to a risk assessment and implementation of biosecurity procedures (fallowing, propagation, grow out and use of screened animals) which minimizes the risk of expression of IHHNV. The use of a brand new hatchery building on site also helped in resetting routine hygiene procedures during production and in controlling incoming and outgoing items (shrimp, water, feed, personnel, equipment, pests and wastes). IHHNV has not been detected on analysed samples since then nor have any symptoms been found during experimental or broodstock growout. Keeping this control alive is considered as a useful tool to lower the risk of potential health threats, to get a better understanding in case of an outbreak, and to increase the reliability of experimental results.
Les crevettes originaires d’Hawaii et conservées au LEAD St-Vincent, dans le cadre du programme d’introduction de variabilité génétique dans le cheptel Calédonien, ont progressivement montré une sensibilité importante au virus IHHNV, agent de la Nécrose Hypodermale et Hématopoïétique Infectieuse (mortalité, croissance ralentie, déformations). Les risques d’une transmission génétique de cette sensibilité à leur descendance à moyen terme, et de son développement par rupture de l’équilibre hôte/pathogène sur la souche dite « Calédonienne » jusqu’alors considérée comme résistante à l’IHHN, ont conduit à partir d’octobre 2008, avec l’accord et l’appui de l’UPRAC et de la DAVAR, à la suppression des animaux hawaiiens ou hybrides encore présents dans les bassins de terre du LEAD St-Vincent, au vide sanitaire de ces derniers, et au repeuplement contrôlé du site. D’autre part, le virus IHHN est soupçonné d’avoir pu affecter les animaux utilisés dans les expérimentations menées au LEAD-St-Vincent (mortalités, déformations, croissance réduite), influençant donc potentiellement leur bon déroulement et celui des programmes de recherches. Les obstacles soulevés par l’expression du virus IHHN ont donc initié depuis 2008 une prise de conscience et la mise en place de démarches de biosécurité dans certains points de la filière. A la station de St-Vincent, cette démarche s’est traduite par une identification/évaluation des risques et l’application de mesures (vide sanitaire, reproduction, élevage et utilisation des animaux contrôlés) chacune dotée de procédures qui regroupées, minimisent le risque d’introduction et de dissémination de l’IHHNV. La prise en main de la nouvelle structure d’écloserie sur le site de la SASV a également été mise à profit pour revoir les procédures d’hygiène de routine dans la conduite des productions et dans le contrôle des flux intrants et sortants (animaux, eau, aliments, personnel, équipement, nuisibles, déchets). Aucune détection d’IHHNV sur les échantillons prélevés n’a depuis été observée, de même qu’aucun symptôme de l’expression de cette maladie sur les animaux en élevage sur le site de Saint-Vincent. La poursuite de ces mesures est envisagée comme un outil d’aide à la minimisation des problèmes potentiels, à leur compréhension en cas d’apparition, et à la fiabilisation des résultats.

Droits : 2010 Ifremer
http://archimer.ifremer.fr/doc/00118/22949/20776.pdf
http://archimer.ifremer.fr/doc/00118/22949/