Éditeur(s) : UNDP Guyana UNDP Guyana ( Guyana )
Résumé : (Funding) Support for the development of the technical infrastructure and partner training provided by the United States Department of Education TICFIA program.
While the global response to HIV and AIDS has realized several successes in achieving universal access to prevention, care and treatment to date, challenges persist in ensuring equal access to these services for most at risk populations. The epidemiology of HIV reflects a stark disparity in access to prevention and treatment services for neglected most-at risk populations, such as men who have sex with men (MSM). World-wide, MSM often experience higher rates of HIV relative to the total population. The reasons for this dynamic are multi-faceted and include high risk behaviors, and cultural as well as structural barriers. For MSM in developing countries, for example, basic services for prevention and treatment of HIV infection have yet to reach the large majority of men. Homophobia and discrimination limit access of MSM to prevention services and markedly increase vulnerability, as do criminalization of same-sex behavior. Decriminalization of same-sex behavior is a structural intervention for prevention of HIV infection and has recently been embraced by a nonbinding statement from the United Nations (Beyrer C,Clin Infect Dis. 2010 May 15;50 Suppl 3:S108-13) In the Caribbean, all of the above mentioned barriers exist. In fact, recent evidence demonstrates that there is a correlation between the decriminalization of homosexuality and lower rates of HIV (UNAIDS). This correlation is attributed to improved access to services. Therefore, The United Nations Development Program (UNDP) has recently launched an initiative to address the current situation regarding men who have sex with men in Guyana where the HIV prevalence in this population is 19.4% in contrast to 1.8% in the total population. This rapid assessment has been commissioned to supplement two previous studies that were conducted in Guyana in informing the design of upcoming activities to support local capacity building to enhance access to services and respect for the human rights protections for MSM. Unfortunately, in Guyana, like much of the Caribbean, MSM tend to be a hard to reach population, perhaps due to elevated levels of stigma and discrimination and difficulty in accessing men who might participate in high risk same sex behaviors yet do not self-identify as an MSM. As a result, there is a relative paucity of data concerning the knowledge, attitudes and behaviors of this total population in Guyana. (i.e. those who self –identify and those who do not) The baseline report is organized as follows: the methodology is explained followed by the study limitations, the review (literature and desk). The report then proceeds with describing the reality of work and working with sexual and gender minorities in Guyana, the status quo and entry points. The main findings of the capacity assessment and focus groups are then discussed. Issues relating to the uniformed forces and health services providers are then presented followed by discussions and conclusions.

Droits : All rights reserved by the source institution.

Éditeur(s) : University of Florida University of Florida ( Gainesville, FL )
Résumé : Sustainable Development Practice (MDP) Program final field practicum report
The MDP Program is administered jointly by the Center for Latin American Studies and the Center for African Studies.

Droits : Copyright Hans Goertz. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
http://ufdc.ufl.edu/AA00023803/00001

Résumé : (Statement of Responsibility) by John Burton Iverson III.
(Thesis) Thesis--University of Florida.
(Bibliography) Bibliography: leaves 353-378.
Typescript.
Vita.
Turks and Caicos Islands
UF

Droits : Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
000185664
03349845
AAV2250

Éditeur(s) : Digital Library of the Caribbean ( dLOC ) Digital Library of the Caribbean ( dLOC ) ( Miami, FL )

http://ufdc.ufl.edu/UF00076717/00001

Éditeur(s) : HAL CCSD Seismological Society of America
Résumé : International audience
Abstract The continuous record of large surface-rupturing earthquakes along the Dead Sea fault brings unprecedented insights for paleoseismic and archaeoseismic research. In most recent studies, paleoseismic trenching documents the late Holocene faulting activity, while tectonic geomorphology addresses the long-term behavior (>10 ka), with a tendency to smooth the effect of individual earthquake rupture events (Mw >7). Here, we combine historical, archaeological, and paleoseismic investigations to build a consolidated catalog of destructive surface-rupturing earthquakes for the last 14 ka along the left-lateral Jordan Valley fault segment. The 120- km-long fault segment limited to the north and the south by major pull-apart basins (the Hula and the Dead Sea, respectively) is mapped in detail and shows five subsegments with narrow stepovers (width < 3 km). We conducted quantitative geomorphology along the fault, measured more than 20 offset drainages, excavated four trenches at two sites, and investigated archaeological sites with seismic damage in the Jordan Valley. Our results in paleoseismic trenching with 28 radiocarbon datings and the archaeoseismology at Tell Saydiyeh, supplemented with a rich historical seismic record, document 12 surface-rupturing events along the fault segment with a mean interval of ∼1160 yr and an average 5 mm=yr slip rate for the last 25 ka. The most complete part of the catalog indicates recurrence intervals that vary from 280 yr to 1500 yr, with a median value of 790 yr, and suggests an episodic behavior for the Jordan Valley fault. Our study allows a better constraint of the seismic cycle and related short-term variations (late Holocene) versus long-term behavior (Holocene and late Pleistocene) of a major continental transform fault.
ISSN: 0037-1106

hal-00747401
https://hal.archives-ouvertes.fr/hal-00747401
DOI : 10.1785/0120100097

Éditeur(s) : American Geophysical Union
Résumé : As part of the French CLIPPER project, an eddy permitting model of the Atlantic circulation has been run for 22 years. The domain has open boundaries at Drake passage and at 30 degreesE, from Africa to Antarctica. The simulated mean circulation, as well as the eddy activity, is satisfactory for a 1/3 degrees model resolution, and the meridional heat transport at 30 degreesS is within the range estimated from observations. We use the "mixed" open boundary algorithm of Barnier et al. [1998], which has both a radiation condition and a relaxation to climatology. The climatological boundary forcing strongly constrains the solution in the whole domain. The model heat balance adjusts through the surface (heat flux retroaction term) more than the open boundaries. The radiation phase velocities calculated within the algorithm are analyzed. This shows, quite surprisingly, that both the eastern and western boundaries have a similar behavior, regardless of the preferred directions for advection (mainly eastward) and wave propagation (mainly westward). Our results confirm that open boundary algorithms behave differently according to the dynamics of the region considered. The passive boundary condition that Penduff et al. [2000] applied successfully in the north eastern Atlantic does not work in the present South Atlantic model. We emphasize the need for a careful prescription of the climatology at the open boundary, for which a new approach based on synoptic sections is implemented.
Journal of Geophysical Union - Research C - Oceans (0148-0227) (American Geophysical Union), 2001-10 , Vol. 106 , N. C10 , P. 22115-22129

Droits : 2001 American Geophysical Union
http://archimer.ifremer.fr/doc/2001/publication-454.pdf
DOI:10.1029/2000JC000376
http://archimer.ifremer.fr/doc/00000/454/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : A major goal of natural resource managers is to foster and maximize environmentally responsible behavior among resource users. Interpretation is the process of conveying a message to someone to (a) enhance the awareness and appreciation that the person has with their surroundings, and to (b) encourage pro-environmental actions. It is one management tool that can be used to influence the actions or inactions of recreational visitors. Effective interpretation prompts the target audience to take action and provides opportunities for the audience to take action. An understanding of behavior and behavior change guides interpretive efforts so that they are effective in influencing behavior. This paper investigates the application of behavioral principles to test the most effective interpretive messages in influencing snorkeler behavior in Mombasa Marine Park. Key messages were incorporated into a training workshop for all the snorkel boat operators and associated crew enabling them to deliver an interpretation program to their clientele. Results indicate that the introduced interpretation program successfully influenced the behavior of snorkeling clients (i.e. led to more pro-environmental snorkel behavior), and increased visitor satisfaction (largely due to the transfer of information through the guide).
Un objectif majeur de gestionnaires des ressources naturelles est de favoriser et d’optimiser le comportement respectueux de l’environnement parmi les utilisateurs des ressources. L’interprétation est le processus de transmission d’un message à quelqu’un pour (a) accroître la sensibilisation et l’appréciation que la personne de son environnement, et pour (b) encourager les actions pro-environnementales. C’est un outil de gestion qui peut être utilisé pour influencer les actions ou inactions lors des visites de loisirs. Une interprétation efficace oriente les actions du public et lui ouvre des possibilités d’action. Une compréhension du comportement et du changement du comportement guide les efforts d’interprétation afin qu’ils soient plus efficaces dans l’influence du comportement. Cet article étudie l’application des principes comportementaux pour tester l’interprétation la plus efficiente des messages qui influencent le comportement des randonneurs palmés dans le parc marin de Mombasa. Des messages clés ont été incorporés dans un atelier de formation destiné aux exploitants de bateaux de plongée avec tuba et à leur équipage pour formuler un programme d’interprétation à leur clientèle. Les résultats indiquent que le programme d’interprétation mis en place a réussi à influencer le comportement des clients de plongée en apnée (à savoir conduit à un comportement de plongée plus pro-environnement) et à augmenter la satisfaction des visiteurs (en grande partie en raison du transfert de l’information par le guide.
Kenya
Mombasa

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.8840
http://journals.openedition.org/etudescaribeennes/8840

Éditeur(s) : HAL CCSD Society for Personality Research
Résumé : International audience
The purpose of this study was to examine self-efficacy and self-esteem as predictors of claimed and behavioral self-handicapping, and to compare the relationship between behavioral and claimed self-handicaps and athletic performance. A total of 31 basketball players participated in the study. Claimed self-handicaps were significantly negatively correlated with self-esteem whereas behavioral self-handicapping was significantly negatively correlated with self-efficacy. Performance was negatively correlated with behavioral self-handicapping, but was not correlated with claimed self-handicapping. These findings reinforce the conceptual distinction between claimed and behavioral self-handicaps by demonstrating that the two strategies are indeed related to different factors and that they have different consequences for performance.
ISSN: 0301-2212

Droits : info:eu-repo/semantics/OpenAccess
hal-01343254
https://hal.univ-antilles.fr/hal-01343254
https://hal.univ-antilles.fr/hal-01343254/document
https://hal.univ-antilles.fr/hal-01343254/file/Social%20Behavior%20and%20Personality.%20HAL.pdf
DOI : 10.2224/sbp.2008.36.3.391

Éditeur(s) : Population Council Population Council ( New York )
Résumé : (Bibliography) Includes bibliographical references (p. 26).
(Statement of Responsibility) by Julie Becker and Elizabeth Leitman ; introduction by Mahmoud F. Fathalla.
Caption title.
Latin America
Caribbean Area
Latin America
Caribbean Area
Latin America
Caribbean Area
Latin America
Caribbean Area
Latin America
Latin America
Latin America

37499376
99208507

Éditeur(s) : The Population Council The Population Council ( New York N.Y )
Résumé : (Bibliography) Includes bibliographical references.
(Language) English with one article in Spanish.
(Statement of Responsibility) by Magaly Marques ; introduction by John M. Paxman ; afterword by Judith Bruce.
Caption title.
Mexico
Mexico
Mexico
Mexico
Mexico
México

37755303
97139151
8734-0572 ;

Éditeur(s) : Elsevier
Résumé : The individual food-demand behavior of juvenile European sea bass (Dicentrarchus labrax, L.) reared in groups under self-feeding conditions was investigated. The triggering activity on self-feeder, i.e. index of the food-demand activity, agonistic interactions and territorial behavior were monitored for periods of 42 to 68 days in six groups of 50 fish. The specific growth rate was calculated and the brain serotonergic activity was used as a stable index of social stress. Inter-individual differences appeared in triggering activity and three groups were distinguished: 3-5 high-triggering fish, 17-30 low-triggering fish and the remaining individuals were null-triggering fish. There were no significant differences in specific growth rates calculated at the end of the experiment (day 42 or day 68) between individuals with high, low, and null food-demand (ANOVA, p > 0.05). No territorial or agonistic behaviors were observed, however, there were significant differences in brain scrotonergic activity between the three triggering groups (ANOVA, p=0.050 in telencephalon and p=0.004 in cerebellum). Specifically, high-triggering fish had lower serotonergic turnover than low or null-triggering fish. We put forth the hypothesis that fish with low or null-triggering activity could be stressed by the high activity of high-triggering individuals. (c) 2006 Elsevier Inc. All rights reserved.
Physiology & Behavior (0031-9384) (Elsevier), 2007-03 , Vol. 90 , N. 4 , P. 559-566

Droits : 2006 Elsevier Inc. All rights reserved
http://archimer.ifremer.fr/doc/2007/publication-2637.pdf
DOI:10.1016/j.physbeh.2006.11.005
http://archimer.ifremer.fr/doc/00000/2637/

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : This study explores weather perceptions, evaluations and behavior of holiday-tourists to the French Caribbean island of La Martinique. Herein, the importance of selected weather parameters for a ‘typical’ summer holiday, for the choice that was made in coming to Martinique and for planned activities is examined. 32 snapshot interviews were held in two brief time periods within a month. Results illustrated slight differences in climate preferences for respondents depending whether they come from a cold or from a warm climate country, that activity patterns seemed overall little influenced by changing weather conditions and that the experienced weather, which was marked by heavy rains in the first data collection period and by changeable weather in the second, appeared to take only a limited impact on return intentions. Albeit the limited possibility of a pilot study to produce valid and reliable findings, variables and factors which are critical to consider when examining weather perceptions and behaviors have been pointed out and presented in a conceptual model for further research.
Cette étude explore les perceptions et les évaluations des conditions météorologiques et les comportements des vacanciers sur l'île de la Martinique. A ce sujet, l´étude examine l'influence de certains paramètres météorologiques sélectionnés sur des vacances d'été «typiques», sur le choix de la destination Martinique et sur les activités envisagées sur lieu. 32 interviews instantanées ont eu lieu en deux courtes périodes de temps pendant un mois. Les résultats illustraient qu´il y avait de légères différences concernant les préférences climatiques selon que les répondants venaient d'un pays au climat froid ou chaud, que les schémas d'activité semblaient généralement peu influencés par les changements météorologiques et que le temps - marquées par de fortes pluies dans la première période de la collecte de données et par un temps variable dans la seconde période - semblait n´avoir qu´un impact limité sur les intentions à revenir à la Martinique. Bien que l´étude pilote n´ait que des possibilités limitées de fournir des résultats valides et fiables, elle identifie les variables et les facteurs qui sont essentiels à considérer lors d´un projet de recherche qui examine la perception des conditions météorologiques par les touristes et les comportements qui en résultent. Ces facteurs sont présentés dans un modèle conceptuel.
Martinique

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5323
http://journals.openedition.org/etudescaribeennes/5323

Éditeur(s) : Academic Press Ltd- Elsevier Science Ltd
Résumé : Several empirical and theoretical studies have shown how the exploitation of food sources, the choice of resting sites or other types of collective decision-making in heterogeneous environments are facilitated and modulated by social interactions between conspecifics. It is well known that many pelagic fishes live in schools and that this form of gregarious behavior provides advantages in terms of food intake and predator avoidance efficiency. However, the influence of social behavior in the formation of aggregations by tuna under floating objects (FOBs) is poorly understood. In this work, we investigated the collective patterns generated by different theoretical models, which either include or exclude social interactions between conspecifics, in the presence of two aggregation sites. The resulting temporal dynamics and distributions of populations were compared to in situ observations of tuna behavior. Our work suggests that social interactions should be incorporated in aggregative behavior to reproduce the temporal patterns observed in the field at both the individual and the group level, challenging the common vision of tuna aggregations around FOBs. Our study argues for additional data to further demonstrate the role of social behavior in the dynamics of these fish aggregations. Understanding the interplay between environmental and social factors in the associative behavior of fish with FOBs is necessary to assess the consequences of the widespread deployment of artificial FOBs by fishermen.
Journal Of Theoretical Biology (0022-5193) (Academic Press Ltd- Elsevier Science Ltd), 2014-10 , Vol. 359 , P. 161-170

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00195/30638/29091.pdf
DOI:10.1016/j.jtbi.2014.06.010
http://archimer.ifremer.fr/doc/00195/30638/

Éditeur(s) : HAL CCSD Elsevier
Résumé : This paper presents a numerical investigation on the mechanical behavior of cemented granular materials by means of discrete element simulations. In particular, two conceptual elements of this behavior were explored: the yield surfaces and the plastic potentials, as defined in the framework of elastoplastic constitutive models. For this purpose, we implemented a contact model that mimics the mechanical behavior of cemented bonds, we constructed a set of polydisperse samples with different solid fractions, and we tested these samples by means of a biaxial device with four rigid walls. The yield surfaces and plastic potentials were thus obtained and analyzed as functions of the solid fraction of the material, drawing interesting conclusions, confirming previous experimental findings, and, consequently, evidencing the great potential of discrete element simulations in exploring the behavior of real cemented geomaterials.
ISSN: 0266-352X

hal-00853748
https://hal.archives-ouvertes.fr/hal-00853748
DOI : 10.1016/j.compgeo.2012.11.001

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
With the growing use of selective serotonin reuptake inhibitor medications (SSRIs) for the treatment of depression during the perinatal period, questions have been raised about the longterm impact of these medications on development. We aimed to investigate how developmental SSRI exposure may alter affect-related behaviors and associated molecular processes in offspring using a rodent model of maternal stress and depression. For this purpose, prenatally stressed or non-stressed male offspring were exposed to fluoxetine (5 mg/kg/day) or vehicle, via lactation, until weaning. Primary results show that postnatal fluoxetine exposure differentially altered anxiety-like behavior by increasing anxiety in non-stressed offspring and decreasing anxiety in prenatally stressed offspring. In the hippocampus, developmental fluoxetine exposure decreased BDNF IV and TrkB mRNA expression. Prenatal stress alone also decreased escape behaviors and decreased hippocampal BDNF IV mRNA expression. These data provide important evidence for the long-term programming effects of early-life exposure to SSRIs on brain and behavior.
ISSN: 0012-1630

hal-01305478
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01305478/file/Developmental%20SSRIs%2C%20anxiety%20and%20BDNF_accepted.pdf
DOI : 10.1002/dev.21385

Éditeur(s) : Publ. CNEXO (France) (Actes Colloq.)(no. 7)
Résumé : The present development of Peneid shrimp culture is limited by the problem set by the routine obtainment of reproduction in captivity. In Polynesia where no species of commercial interest is found naturally, this obtainment is a necessary prerequisite. The observations at the Centre Océanologique du Pacifique of CNEXO were made on 6 species of the genus Penaeus (P. merguiensis, P. aztecus, P. japonicus, P. monodon, P. vannamei and P. stylirostris) raised and maintained in 12 m² outdoortanks. At temperatures, between 25 and 32°, a salinity of 35 and a pH of 8,2, maturations and spawnings are seen throughout the year and several generations were obtained : P. merguiensis, F7 ; P. aztecus et P. japonicus, F3 ;P. monodon, F2 ; P. stylirostris and P. vannamei F1. For P. aztecus et P. mondon maturation is induced by unilateral eyestalk ablation. The animals behavior copulation and external signs of ovarian, development are described. The factors which seem essential to the proper progress of maturation are the temperature, the light intensity, the food and the state of health of the animals.
Le développement des élevages de crevettes Pénéidés est actuellement limité par les problèmes que pose l'obtention en routine de la reproduction en captivité. En Polynésie où aucune espèce d'intérêt commercial ne se trouve à l'état naturel, cette obtention était un préalable nécessaire. Les observations effectuées au Centre Océanologique du Pacifique du CNEXO ont porté sUr 6 espèces du genre Penaeus (P. merguiensis, p. aztecus, P. japonicus, P. monodon, P. vannamei et P. stylirostris) élevées et maintenues dans des bacs extérieurs de 12 m² en circulation ouverte. Avec des températures variant de 25 à 32°, une salinité de 35 et un pH voisin de 8,2, maturations et pontes s'obserVent toute l'année et plusieurs générations ont été obtenues : P. merguiensis, F7 ; P. aztecus et P. japonicus, F3 ;P. monodon, F2 ; P. stylirostris et P. vannamei, F1. Pour P. aztecus et P. mondon, la maturation est induite par épédonculation unilatérale. Le comportement des animaux, la copulation et les signes extérieurs du développement des ovaires sont décrits. Les facteurs qui paraissent essentiels au bon déroulement du processus de maturation sont la température l'éclairement, l'alimentation et l'état de santé des animaux

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1977/publication-6073.pdf
http://archimer.ifremer.fr/doc/00000/6073/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Recent research has linked early life exposure to selective serotonin reuptake inhibitor medications (SSRIs) to modifications of social behaviors in children. Serotonin is a key regulator of neurodevelopment, social behaviors and mental health, and with the growing use of SSRIs to treat maternal affective disorders during the perinatal period, questions have been raised about the benefits and risks of perinatal SSRI exposure on the developing child. This review will highlight how perinatal SSRIs affect maternal care and neurodevelopmental outcomes related to social affiliative behaviors in offspring; such as play behaviors, social interactions, reproductive behaviors, and maternal care of the next generation. We will also review how early life exposure to SSRIs can alter related neurobiology, and the epigenome. Both clinical research and findings from animal models will be discussed. Understanding the impact of perinatal SSRIs on neurobehavioral outcomes will improve the health and well-being of subsequent generations.
ISSN: 0149-7634

hal-01619303
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01619303
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01619303/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01619303/file/Perinatal%20selective%20serotonin%20reuptake%20inhibitor%20medication_revised.pdf
DOI : 10.1016/j.neubiorev.2017.04.023

Éditeur(s) : HAL CCSD American Geophysical Union
Résumé : International audience
This paper presents a multicontinuum approach to model fractal temporal scaling of catchment response in hydrological systems. The temporal scaling of discharge is quantified in frequency domain by the transfer function HðxÞ, which is defined as the ratio between the spectra of catchment response and recharge time series. The transfer function may scale with frequency x as HðxÞ x2b. While the classical linear and Dupuit models predict exponents of b52 and b51, observations indicate scalings with noninteger exponents b. Such behaviors have been described by multifractal models, which, however, often lack a relation to the medium characteristics. We revisit and extend the classical linear Dupuit aquifer models and discuss their physical meanings in the light of the resulting aquifer dynamics. On the basis of these classical models, we derive a multicontinuum approach that provides physical recharge models which are able to explain fractal behaviors with exponents 1=2 < b < 2. Furthermore, this approach allows to link the fractal dynamics of the discharge process to the physical aquifer characteristics as reflected in the distribution of storage time scales. We systematically analyze the catchment responses in the proposed multicontinuum models, and identify and quantify the time scales which characterize the dynamics of the catchment response to recharge.
ISSN: 0043-1397

insu-00952537
https://hal-insu.archives-ouvertes.fr/insu-00952537
https://hal-insu.archives-ouvertes.fr/insu-00952537/document
https://hal-insu.archives-ouvertes.fr/insu-00952537/file/russian.pdf
DOI : 10.1002/2013WR014255

Éditeur(s) : HAL CCSD
Résumé : International audience
EmailPrintRequest PermissionsThe emergence of new communication means such as online newspapers and exchange and sharing websites allow us to go further in the understanding of diffusion phenomena. Indeed, these public discussion areas are now firmly established in our societies and are known to be strong sensors of both human behaviors and collective feelings. In this paper we focus on diffusion phenomena that occur on Twitter and we propose a set of measures that aims to characterize globally and locally the processes. Our objective is to identify what are the conditions in which a person decides to forward the information. Our measures have been used to study two events occurred in January 2015: the presentation of Microsoft HoloLens, a new augmented reality headset, and the political election in Greece. The results obtained show a strong heterogeneity in the individual behaviours involved in the diffusion process. Our approach has been implemented into a graphical tool which is able to conduct real time analysis on any kind of topics occurring on Twitter.
IEEE International Conference on Research Challenges in Information Science (RCIS)
Athens, Greece

hal-01312382
https://hal.univ-antilles.fr/hal-01312382
DOI : 10.1109/RCIS.2015.7128894

Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
The association of experimental data showing that the plastic deformation of olivine, the main constituent of the upper mantle, is highly anisotropic and the ubiquitous seismic anisotropy in the upper mantle, which indicates that olivine crystals show coherent orientations over scales of tens to hundreds of kilometers, implies that the long-term deformation in the upper mantle is anisotropic. We propose a multiscale approach, based on a combination of finite element and homogenization techniques, to model the deformation of a lithospheric plate while fully considering the mechanical anisotropy stemming from a strain-induced orientation of olivine crystals in the mantle. This multiscale model explicitly takes into account the evolution of crystal preferred orientations (CPO) of olivine and of the mechanical anisotropy during the deformation. We performed a series of numerical experiments simulating the uniaxial extension of a homogeneous (100% olivine) but anisotropic plate to test the role of the olivine CPO on the plate mechanical behavior and the link between CPO and mechanical anisotropy evolution. Even for this simple solicitation, different orientations and intensity of the initial olivine CPO result in variable plate strengths and deformation regimes. A plate with an initial CPO where the olivine [100] and [010] axes are concentrated at 45 degrees to the extension direction has high resolved shear stresses on the easy (010)[100] and (001)[100] slip systems of olivine. This results in low strength and in deformation by transtension. Plates with an initial CPO where the maximum of [100] axes is parallel or normal to the extension direction show a high initial strength. Isotropic plates have an intermediate behavior. The progressive rotation of olivine [100] axes toward the imposed stretching direction results in hardening in all models, except in those characterized by an initial concentration of olivine [100] axes normal to the imposed extension, in which softening is followed by hardening.
ISSN: 1525-2027

hal-00420063
https://hal.archives-ouvertes.fr/hal-00420063
DOI : 10.1029/2009GC002423