Éditeur(s) : Université des Antilles Études caribéennes
Résumé : El Caribe colombiano ha experimentado un acelerado proceso de urbanización y desarrollo turístico en los últimos 50 años. Solo en una ciudad como Cartagena de Indias (la ciudad turística por excelencia de Colombia), datos referidos al periodo noviembre 2009 – enero 2015, mostraron un incremento en la llegada de turistas cercano al 20%. Después de un gran número de encuestas realizadas alrededor del mundo, se encontró que los parámetros en que se basan los turistas a la hora de preferir una playa son: i) la seguridad, ii) el paisaje, iii) calidad del agua, iv) basuras, v) instalaciones. El paisaje es uno de los recursos costeros y por lo tanto su evaluación es una herramienta importante para los gestores y planificadores del litoral a la hora de la realización de planes de conservación, protección, desarrollo y manejo. Este trabajo se basa en la evaluación del valor paisajístico de las playas que constituyen la base de la economía de muchas ciudades costeras en el mundo y en especial de la zona central de litoral Caribe colombiano. Un problema importante en la evaluación del paisaje es la incapacidad de algunas metodologías de reflejar correctamente las percepciones de la gente, debido al alto peso que tienen algunos aspectos subjetivos (p. ej. altura de una geoforma).En este trabajo se presenta la evaluación del paisaje realizada para la zona central de Caribe colombiano (37 playas de los departamentos de Sucre, Bolívar y Atlántico) utilizando la lógica matemática y matrices ponderadas (fuzzy logic mathematics - parameter weighting matrices) las cuales permiten disminuir la subjetividad y cuantificar con exactitud la incertidumbre. Para la evaluación se utilizó una lista de chequeo que está conformada por 26 parámetros, 18 físicos (acantilados, playas, plataformas rocosas, dunas, características de los valles, forma del relieve, mareas, paisaje costero, color del agua y restos de vegetación), y 8 antropogénicos (ruido, basura, descarga de aguas residuales, grado de modificación y de construcción del medio, tipos de acceso, línea del horizonte y estructuras antrópicas). Los parámetros fueron calificados en una escala de 1 a 5 (presencia/ausencia o poca/alta calidad) y, con el fin de cuantificar la incertidumbre y excesos derivados de la subjetividad que pudo haber tenido la evaluación de los parámetros, se utilizó la lógica difusa (fuzzy logic). A la par, un sistema de matrices, se empleó para asignar valores de peso de acuerdo a las preferencias y prioridades de los usuarios. Como resultado de estos análisis lógico-estadísticos se obtuvo un valor (D) el cual resume la evaluación del paisaje en 5 clases que van desde la CLASE 1 (zona litoral sumamente atractiva) hasta la CLASE 5 (playas urbanas muy poco atractivas). De los 37 sectores estudiados, ninguno puede ser considerado como una zona litoral sumamente atractiva, mientras que 15 corresponden a zonas litorales urbanas poco atractivas, el resto de las playas (22) se ubicó entre las clases 2, 3 y 4. Los resultados obtenidos son útiles para los gestores costeros en la medida que, aunque no es posible mejorar los aspectos naturales de la clasificación, si es posible mejorar muchos de los parámetros antropogenicos y, de esta forma, hacer que una playa mejore su clasificación y sea paisajísticamente más atractiva.
In the past few years, the Colombian Caribbean coast has experienced rapid tourism development which has not been accompanied with a similar increase in urbanization facilities. For example, the city of Cartagena de Indias (the most famous tourist destination of Colombia), data related to November 2009 – January 2015 period, showed an increase of 20% in tourist arrivals. A large number of surveys developed in Europe found that the most critical parameters for tourists, when they choose a beach, are: i) security, ii) scenery, iii) water quality, iv) litter, v) facilities. Scenery is one of the most significant coastal resources. Therefore, its evaluation is a valuable tool for coastal managers when developing conservation and protection plans. This proposal provides coastal scenery assessment of 37 beaches along the North Colombian Caribbean littoral by analysing 26 physical and human factors. Results were weighted (not all parameters have equal weight) and subjected to fuzzy logic mathematics in order to reduce recorder judgment subjectivity. The sites were categorised into five classes; Class 1 locations had top grade scenery; Class 5 poor scenery. Of the 37 sectors studied, currently none can be considered as an extremely attractive coastal area (class1), while 15 were unattractive urban coastal areas (class 5), the rest of the beaches (22) placed in classes 2, 3 and 4. Classification of analysed sites depends on the geological setting and degree of human occupation. The technique opens new perspectives for analysis of the potential for coastal tourism development in natural areas and scenic quality improvement of current tourist developed areas. Concerning coastal management issues, emphasis should be given to the upgrading of human parameters eliminating litter and sewage evidence, vegetation debris and enhancing beach nourishment works. This proposal can help in moving some locations from their present status to a higher one.
Caraïbes
Colombie

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.9326
http://journals.openedition.org/etudescaribeennes/9326

Éditeur(s) : HAL CCSD European Geosciences Union (EGU)
Résumé : International audience
Holocene climate fluctuations and human activity since the Neolithic have shaped present-day Mediter-ranean environments. Separating anthropogenic effects from climatic impacts to better understand Mediterranean pale-oenvironmental changes over the last millennia remains a challenging issue. High-resolution pollen analyses were un-dertaken on two cores from the Palavasian lagoon system (Hérault, southern France). These records allow reconstruction of vegetation dynamics over the last 4500 years. Results are compared with climatic, historical and archeological archives. A long-term aridification trend is highlighted during the late Holocene, and three superimposed arid events are recorded at 4600–4300, 2800–2400 and 1300–1100 cal BP. These periods of high-frequency climate variability coincide in time with the rapid climatic events observed in the Atlantic Ocean (Bond et al., 2001). From the Bronze Age (4000 cal BP) to the end of the Iron Age (around 2000 cal BP), the spread of sclerophyllous taxa and loss of forest cover result from anthropogenic impact. Classical Antiquity is characterized by a major reforestation event related to the concentration of rural activity and populations in coastal plains leading to forest recovery in the mountains. A major regional deforestation occurred at the beginning of the High Middle Ages. Around 1000 cal BP, forest cover is minimal while the cover of olive, chestnut and walnut expands in relation to increasing human influence. The present-day vegetation dominated by Mediterranean shrubland and pines has been in existence since the beginning of the 20th century.
ISSN: 1814-9324

hal-01447627
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627/document
https://hal-univ-tlse2.archives-ouvertes.fr/hal-01447627/file/Azuara%20et%20al%202015_cor.pdf
DOI : 10.5194/cp-11-1769-2015

Éditeur(s) : HAL CCSD
Résumé : Co-encadrement assuré par le Groupement pour le Développement de la Télédétection Aérospatiale (GDTA) Diplôme : DESS
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
This document proposes a new map of the Eastern Guyana Shield, with the SPOT4-VEGETATION remotesensed datas of the year 2000. A new synthesis method, with the mean value, was applied and compared with the Maximum Value Method (WVC). To prepare this datas for the synthesis, a cloud filter was defined :BSC (BEST Sky Clear). With this results, an ISODATA classification was proceeded, and, produces 25 classes to detail the tropical maist forest with the 1 km low resolution. To valid this result, this document propose a method with the higthresolution datas Landsat 7 ETM+. This method aims to guide the ground truth and goes thoroughly into the description of the moist tropical forest classes. The sample, used to try this method, shows the boundaries and the constraints of this method. This points are debating in the discussion. Finally, the perspectives to develop the method are presented in the conclusion.
Ce document propose une nouvelle cartographie du Bouclier Oriental Guyanais à l'aide d'images satellites SPOT4-VEGETATION de l'année 2000. Une nouvelle méthode de synthèse annuelle, utilisant la valeur moyenne de la radiométrie, a été appliquée et comparée à la méthode du Maximum Value Composite (MVC). A cette occasion, un filtre de nuage a été défini pour préparer les données à cette synthèse : le filtre BSC (Best Sky Clear). Sur la base de ce résultat, une classification ISODATA a été réalisée, produisant 25 classes, et mettant en évidence les différents milieux forestiers des tropiques humides à une résolution spatiale de 1 km. Pour valider la classification, une méthode est proposée utilisant des images hautes résolutions Landsat 7 ETM+. Cette méthode permet de cadrer les vérifications sur le terrain et d'approfondir la définition des classes de forêt tropicale humide. L'échantillon utilisé pour tester la méthode met en évidence les limites et contraintes de la démarche proposée. Ces points sont exprimés dans la discussion. Enfin les perspectives de développements sont abordées dans la conclusion.
https://hal.archives-ouvertes.fr/hal-01189195

hal-01189195
https://hal.archives-ouvertes.fr/hal-01189195
PRODINRA : 13538

Éditeur(s) : HAL CCSD European Geosciences Union (EGU)
Résumé : International audience
Pollen and clay mineralogical analyses of a Holocene sequence from Sebkha Boujmel (southern Tunisia) traces the climatic and environmental dynamics in the lower arid bioclimatic zone over the last 8000 years. During the Mid- to Late Holocene transition, between 8 and 3 ka, a succession of five wet/dry oscillations is recorded. An intense arid event occurs between 5.7 and 4.6 ka. This episode marks the onset of a long-term aridification trend with a progressive retreat of Mediterranean woody xerophytic vegetation and of grass steppes. It ends with the establishment of pre-desert ecosystems around 3 ka. The millennial-scale climate change recorded in the data from Sebkha Boujmel is consistent with records from the south and east Mediterranean, as well as with climatic records from the desert region for the end of the African Humid Period (AHP). Eight centennial climatic events are recorded at Sebkha Boujmel and these are contemporary with those recorded in the Mediterranean and in the Sahara. They indicate a clear coupling between the southern Mediterranean and the Sahara before 3 ka. The event at 4.2 ka is not evidenced and the link between events recorded in Sebkha Boujmel and the North Atlantic Cooling events is clearer from 3 ka onwards. These variations indicate the importance of climatic determinism in the structuring of landscapes, with the establishment of the arid climatic conditions of the Late Holocene. It is only from 3 ka onwards that the dynamic of plant associations is modified by both human activity and climatic variability. The climatic episodes identified during the historic period indicate strong regionalisation related to the differential impact of the North Atlantic Oscillation (NAO) and the Mediterranean Oscillation (MO) on the Mediterranean basin. The local human impact on regional ecosystems is recorded in the form of episodes of intensification of pastoral and/or agricultural activities. The development of olive production and of several taxa associated with agriculture attest to increasing sedentism among human populations during Classical Antiquity. The significant increase in Artemisia (wormwood) between 1.1 and 0.8 ka (850–1150 AD) is linked to intensive pastoral activity, associated with heightened interannual and/or seasonal climatic instability. A complete re-shaping of the landscape is recorded during the 20th century. The remarkable expansion of the olive tree, and the deterioration of regional ecosystems with the spread of desert species, is linked to recent local socio-economic changes in Tunisia.
ISSN: 1814-9324

hal-01319967
https://hal.archives-ouvertes.fr/hal-01319967
https://hal.archives-ouvertes.fr/hal-01319967/document
https://hal.archives-ouvertes.fr/hal-01319967/file/cp-12-1339-2016.pdf
DOI : 10.5194/cp-12-1339-2016

Éditeur(s) : Taylor & Francis
Résumé : This study is an attempt to produce an assessment of the impact of shrimp aquaculture in the Mekong Delta (Viet Nam) on mangrove ecosystems. For this exercise we selected two sub-areas (Ca Mau and Tra Vinh provinces) encompassing a variety of land uses and ecological conditions. Twenty stations in Tra Vinh and 15 stations in Ca Mau have been surveyed several times from September 2000 to March 2002. Field investigations included mangrove soils studies, measurements of pH and salinity of the water, analysis of mangrove flora, and density and structure of the vegetation. Four Systeme Probatoire de l'Observation de la Terre (SPOT) scenes were used for the discrimination of mangrove types and for the delineation of landscape units. For the first time, five ecologically distinct landscape classes were identified and delineated. Their possible links with the farming and yields of high valued species of shrimps, especially the giant tiger shrimp (Penaeus monodon) destined for export markets, need further studies. Since 1965, about 30% of mangrove ecosystems have been lost in Ca Mau Province and more than 30% of present mangroves are replanted monospecific stands. To the best of our knowledge, this is the first study which demonstrates that, in spite of deep and ancient man interactions in the Mekong Delta, five ecologically distinct classes of land use can be defined. Satellite surveys confirm a clear distribution of landscape units with possible links with shrimp aquaculture potentialities.
International Journal of Remote Sensing (0143-1161) (Taylor & Francis), 2004-11 , Vol. 25 , N. 21 , P. 4795-4812

Droits : 2004 Taylor & Francis
http://archimer.ifremer.fr/doc/2004/publication-2303.pdf
DOI:10.1080/01431160412331270858
http://archimer.ifremer.fr/doc/00000/2303/

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : The patterns of the distribution of fungal species and their potential interactions with trees remain understudied in Neotropical rainforests, which harbor more than 16,000 tree species, mostly dominated by endomycorrhizal trees. Our hypothesis was that tree species shape the non-mycorrhizal fungal assemblages in soil and litter and that the diversity of fungal communities in these two compartments is partly dependent on the coverage of trees in the Neotropical rainforest. In French Guiana, a long-term plantation and a natural forest were selected to test this hypothesis. Fungal ITS1 regions were sequenced from soil and litter samples from within the vicinity of tree species. A broad range of fungal taxa was found, with 42 orders and 14 classes.Significant spatial heterogeneity in the fungal communities was found without strong variation in the species richness and evenness among the tree plots. However, tree species shaped the fungal assemblages in the soil and litter, explaining up to 18 % of the variation among the communities in the natural forest.These results demonstrate that vegetation cover has an important effect on the structure of fungal assemblages inhabiting the soil and litter in Amazonian forests, illustrating the relative impact of deterministic processes on fungal community structures in these highly diverse ecosystems.
ISSN: 0095-3628

hal-01595373
https://hal.archives-ouvertes.fr/hal-01595373
DOI : 10.1007/s00248-016-0839-0
PRODINRA : 395655
PUBMED : 27645139

Éditeur(s) : HAL CCSD Wiley
Résumé :  
A digital land cover map of South America has been produced using remotely sensed satellite data acquired between 1995 and the year 2000. The mapping scale is defined by the 1 km spatial resolution of the map grid-cell. In order to realize the product, different sources of satellite data were used, each source providing either a particular parameter of land cover characteristic required by the legend, or mapping a particular land cover class. The map legend is designed both to fit requirements for regional climate modelling and for studies on land cover change. The legend is also compatible with a wider, global, land cover mapping exercise, which seeks to characterize the world's land surface for the year 2000. As a first step, the humid forest domain has been validated using a sample of high-resolution satellite images. The map demonstrates both the major incursions of agriculture into the remaining forest domains and the extensive areas of agriculture, which now dominate South America's grasslands.
ISSN: 1354-1013

hal-01032088
https://hal.archives-ouvertes.fr/hal-01032088
DOI : 10.1111/j.1529-8817.2003.00774.x

Éditeur(s) : Centre français du littoral
Résumé : This study presents the first results of an ongoing research program that aims to derive thematic maps of the intertidal lagoon of Arcachon (SW Atlantic coast of France) from space imagery. At this stage, we present the results of the tests performed on Formosat-2 imagery. Several classification strategies have been tried with the aim to discriminate the sedimentary facies and the main species of the lagoon. The classes calculated by an optimized unsupervised clustering method, based on simulated annealing global minimization technique, were used to train a supervised classification algorithm. This approach allowed us to derive a bio-sedimentary map which overall accuracy is about 84%. Also, this method has the advantage of describing the fraction of vegetation cover of the seagrass.
Cette étude présente les premiers résultats d’un vaste programme de recherche qui ambitionne de définir une méthode de cartographie des platiers intertidaux du Bassin d’Arcachon (France) par télédétection. Les résultats présentés ici concernent les tests effectués sur l’imagerie Formosat-2 dans le but de discriminer les sédiments et les principales espèces végétales de la lagune. Le résultat d'une classification non supervisée optimisée par la méthode du recuit simulé est ensuite utilisé pour entraîner une classification par minimum de distance. Cette approche permet d’obtenir une carte des faciès bio-sédimentaires dont la précision est estimée à plus de 84 %. Cette méthode présente, en outre, un excellent potentiel pour la détermination du pourcentage de couvert végétal des herbiers à zostères.
Paralia (1760-8716) (Centre français du littoral), 2008 , N. 10 , P. 563-572

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00254/36572/35110.pdf
DOI:10.5150/jngcgc.2008.054-L
http://archimer.ifremer.fr/doc/00254/36572/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The separation of the germ line from the soma is a classic concept in animal biology, and depending on species is thought to involve fate determination either by maternally localized germ plasm (''preformation'' or ``maternal inheritance'') or by inductive signaling (classically termed ``epigenesis'' or ``zygotic induction''). The latter mechanism is generally considered to operate in non-bilaterian organisms such as cnidarians and sponges, in which germ cell fate is determined at adult stages from multipotent stem cells. We have found in the hydrozoan cnidarian Clytia hemisphaerica that the multipotent ``interstitial'' cells (i-cells) in larvae and adult medusae, from which germ cells derive, express a set of conserved germ cell markers: Vasa, Nanos1, Piwi and PL10. In situ hybridization analyses unexpectedly revealed maternal mRNAs for all these genes highly concentrated in a germ plasm-like region at the egg animal pole and inherited by the i-cell lineage, strongly suggesting i-cell fate determination by inheritance of animal-localized factors. On the other hand, experimental tests showed that i-cells can form by epigenetic mechanisms in Clytia, since larvae derived from both animal and vegetal blastomeres separated during cleavage stages developed equivalent i-cell populations. Thus Clytia embryos appear to have maternal germ plasm inherited by i-cells but also the potential to form these cells by zygotic induction. Reassessment of available data indicates that maternally localized germ plasm molecular components were plausibly present in the common cnidarian/bilaterian ancestor, but that their role may not have been strictly deterministic.
ISSN: 0012-1606

hal-01544487
https://hal.archives-ouvertes.fr/hal-01544487
DOI : 10.1016/j.ydbio.2012.01.018

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : The tropical coast of Queensland, Australia is experiencing rapid population and tourism growth. Heavy development pressure is being placed on the biophysical environment, which includes the largest sand island in the world (World Heritage listed), Fraser Island. Despite the existence of State planning legislation oriented towards environmental sustainability, it is apparent that little, if any, regard is being paid to the long-term effects of resort and canal-estate development on the underlying biophysical environment of the coast and islands. While the remarkable surface features of the tropical coastal environment such as the surf beaches, the unique dune lakes, and the coastal vegetation, as well as the prolific wildlife, are used as selling points for new settlement and above all tourism, little is known or apparently of major concern with respect to the long term environmental impact of coastal development. While the crowding effect of large numbers of visitors and their impact on the natural environment - through significant degradation, site hardening or lack of proper on-site management – has been identified as a particular problem in certain areas, there is little knowledge of impacts on the underlying coastal geomorphology. In particular, developmental choices are often made in ignorance of, or disregard of, the widespread existence of tropical acid sulfate soils in that coastal environment. Reactive soils such as these can, and do, greatly affect the biophysical outcomes of a development if they are exposed. This paper documents such impacts in the form of a case study of the acid sulfate soil problem in relation to the development of tourist resorts, and suggests that part of the solution is for the State Government to insist on enforceable standards relating to their development for tourism in the coastal zone. These would reduce the use by many resort owners of fancy golf course developments as an environmental cover up to make it look as if they put a lot of effort into protecting the environment….
La côte tropicale du Queensland est confrontée à un accroissement rapide de la population. Les fortes pressions anthropiques pèsent sur le milieu biophysique, qui comprend notamment a plus grande île de sable du monde, un site classé Patrimoine de l’Humanité, Port Hinchinbrook et Fraser Island. Malgré l’existence d’une législation nationale orientée vers la préservation de l’environnement, il est manifeste que peu d’attention est accordée aux effets à long terme des sites touristiques et du développement de l’urbanisation sur ces franges côtières sensibles. L’aspect massif des flux de visiteurs et leurs impacts sur le milieu naturel a été identifié comme un sujet d’inquiétude particulier dans certaines régions. La connaissance des impacts sur la géomorphologie côtière souterraine est très réduite et les choix de développement sont souvent faits dans l’ignorance ou au mépris de la présence répandue de terrains de sulfate d’acide dans ce milieu côtier. Des sols réactifs comme ceux-là peuvent affecter, et affectent, grandement les résultats géophysiques d’un développement lorsqu’ils sont connus. Des études de cas sur le problème des sols de sulfate d’acide suggèrent qu’une partie de la solution pour le gouvernement de l’Etat du Queensland est d’imposer des normes obligatoires pour le développement du tourisme dans la zone côtière.
Australie
Queensland

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.1272
http://journals.openedition.org/etudescaribeennes/1272

Éditeur(s) : HAL CCSD
Résumé : International audience
Ripley’s K function is the classical tool to characterize the spatial structure of point patterns. It is widely used in vegetation studies. Testing its values against a null hypothesis usually relies on Monte-Carlo simulations since little is known about its distribution.We introduce a statistical test against complete spatial randomness (CSR). The test returns the p-value to reject the null hypothesis of independence between point locations. It is more rigorous and faster than classical Monte-Carlo simulations. We show how to apply it to a tropical forest plot. The necessary R code is provided.
International Scholarly Research Network, ISRN Ecology

hal-01502637
https://hal-agroparistech.archives-ouvertes.fr/hal-01502637
https://hal-agroparistech.archives-ouvertes.fr/hal-01502637/document
https://hal-agroparistech.archives-ouvertes.fr/hal-01502637/file/2013_Marcon_Hindawi%20Publishing%20Corporation_%7B7A602F34-6983-47DE-924B-7CDC3B8D14F7%7D.pdf
DOI : 10.1155/2013/753475

Éditeur(s) : HAL CCSD Wiley/Blackwell
Résumé : Whole genome sequencing is helping generate robust phylogenetic hypotheses for a range of taxonomic groups that were previously recalcitrant to classical molecular phylogenetic approaches. As a case study, we performed a shallow shotgun sequencing of eight species in the tropical tree family Chrysobalanaceae to retrieve large fragments of high-copy number DNA regions and test the potential of these regions for phylogeny reconstruction. We were able to assemble the nuclear ribosomal cluster (nrDNA), the complete plastid genome (ptDNA) and a large fraction of the mitochondrial genome (mtDNA) with approximately 1000x, 450x and 120x sequencing depth respectively. The phylogenetic tree obtained with ptDNA resolved five of the seven internal nodes. In contrast, the tree obtained with mtDNA and nrDNA data were largely unresolved. This study demonstrates that genome skimming is a cost-effective approach and shows potential in plant molecular systematics within Chrysobalanaceae and other under-studied groups.
ISSN: 1755-098X

hal-01204217
https://hal.archives-ouvertes.fr/hal-01204217
DOI : 10.1111/1755-0998.12246
PRODINRA : 283530

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
While the populations of large herbivores are being depleted in many tropical rainforests, the importance of their trophic role in the ecological functioning and biodiversity of these ecosystems is still not well evaluated. This is due to the outstanding plant diversity that they feed upon and the inherent difficulties involved in observing their elusive behaviour. Classically, the diet of elusive tropical herbivores is studied through the observation of browsing signs and macroscopic analysis of faeces or stomach contents. In this study, we illustrate that the original coupling of classic methods with genetic and ethnobotanical approaches yields information both about the diet diversity, the foraging modalities and the potential impact on vegetation of the largest terrestrial mammal of Amazonia, the lowland tapir. The study was conducted in the Guianan shield, where the ecology of tapirs has been less investigated. We identified 92 new species, 51 new genera and 13 new families of plants eaten by tapirs. We discuss the relative contribution of our different approaches, notably the contribution of genetic barcoding, used for the first time to investigate the diet of a large tropical mammal, and how local traditional ecological knowledge is accredited and valuable for research on the ecology of elusive animals.
ISSN: 1932-6203

halsde-00676374
https://hal.archives-ouvertes.fr/halsde-00676374
DOI : 10.1371/journal.pone.0025850
PUBMED : 21991372