Processos de formação dos profissionais de reconhecimento e validação de competências

Trabalho de projecto de mestrado, Ciências da Educação (Formação de Adultos), Universidade de Lisboa, Instituto de Educação, 2011

Como se chega ou como nos tornamos docentes no Ensino Superior

The Thesis weaved in the (auto) biographical boarding studies the existence of existential teaching, in the scope of Superior Teaching, guided in the experience and the (auto) formative scope as a theoreticianmethodological support present in the classrooms, being three the essential questions: Which the way of (auto) formation traveled by professors of Superior Teaching, what is, for these citizens, the teaching in Superior Teaching and what they understand from existential teaching according to their narratives. The epistemology of this work, based on Program of After-Graduation in Education of Universidade Federal do Rio Grande do Norte, Support of Research: Professionalization and Formation Lecturing emerges, especially, of the studies and research realized by Ramalho and Nuñez (2005, 2006), Morosini (2001), Pimenta and Anastasiou (2002), Nóvoa (2000), Josso (2004), Dominicé (1988), Catani (2002), and Souza (2004), among other authors, yonder the educational practice exercised by researcher and involved citizens in inquiryformation, what it is confirmed from the three methodological tools that given support to the covered way: Eight topic narratives, a participantcomment and seven laboratories or parallel meeting of formation (EPF's) experimented with licensed teachers that actuate in superior teaching institutions (IES), public and private, localized in the city of Natal/RN. The Thesis points out, in this way, existential education in the guideline of viable and concrete methodological alternatives amongst the problematic of the (auto) formation faced for the professors in Superior Teaching

A Fogueira do conhecimento: religação de saberes e formação

Les récits sur les expériences de vie se constituent en apprentissages signifiants dans le processus d´ auto-formation des éducateurs. La formation est un phenomène qui extrapôle l ambiance scolaire, incluant les expériences qui servent de matrice pour la construction de la connaissance au long de la vie. Dans cette perspective, «la connaissance de soi», telle quelle proposée par SOUZA, NOVOA et JOSSO, est la notion centrale au tour de laquelle se développe cette dissertation. La recherche a comme idée principale transposer pour la realité des professeurs l´exercice reflexif de son enseignement, médiant la redécouverte de ses expériences de vie, a travers des histoires de soi que, potentialisés, peuvent transformer ses pratiques dans la classe scolaire. Je prends comme point de départ mes propres expériences comme éducatrice assumant la conviction de la indissociation entre sujet et objet de la connaissance, comme propose Édgar Morin pour parler de la science de la complexité. Je fais aussi l´usage des récits de six professeurs du réseau publique de l enseigment, révélateurs de la construction de la connaissance appuyée dans la cohérence de la praxis pédagogique avec son mode de comprendre et sentir le monde. Les oeuvres «Mes Démons» d Édgar Morin, «O Tempo e Eu» de Luis da Câmara Cascudo et «O Banquete dos Deuses» de Daniel Munduruku, ont élargit le champs des récits d expériences que se constituent en matrices des processus de formation. Le travail avec les récits de formation démontrent qu´à partir de la réflection du sujet sur sa propre expérience, il est possible de se projéter des nouvelles configurations de la connaissance tenant comme base, la reliaison entre vie, idées, et pratiques pédagogiques. À partir de la métaphore du bûcher il est possible de se comprendre la force de combustion des expériences de vie dans la formation des enseignants

Corporeidade e formação docente: cenário geográfico das histórias de vida

L étude vient de présenter la recherche qui a eu lieu pendent la formation des professeurs d l'Institut d'Enseignement Supérieur Président Kennedy à Natal-RN, dont les sujets son les professeurs de la septième période du Cours Normal Supérieur. L objet d´étude sont les pratiques formatives de ces professeurs en formation par des difficultés qui ils présentaient pour comprendre les relations entre les domaines de connaissance le l interface avec les expériences, et le processus de formation. L objectif a éte identifier dans l expériences ludopoèthiques, les lieus de construction de l autoterritorialité des professeus en tant qu en formation. Parmi les pressuposés théoriques qui ont soutenu le développement de la recherche comprennent: Enseignement Humain ; Corps-espace; Corporéité; Auto-formation et Transdisciplinarité. L'approche de la recherche qualitative adopte les principes de la rechercheaction- formation, dans une perspective etnophenomenologique. La discipline Memorial de Formação avec l'utilisation de jeu de sable,a été le laboratoire des expériences, l outil de la recherche qui a subventionné la construction des narratives autobiographiques. La perspective transdisciplinaire sur l'étude a rassemblé dans la dimension épistémologique les références théoriques de la Géographie, de la corporéité. et des histoires de vie dans la formation. L'Atelier Corps (Bio) Géographique a été développé par cinq rencontres: Paysage du Sensible, Lieu de Sentipensar, Territoires des Découvertes, Région des Savoirs et de l'Espace Géographique de la Ecoformação. Les expériences vécues dans l'Atelier par les participants de la recherche ont permis une sensible et attentive écoute sur leur propre histoire, en donnant la possibilité de la reconstruction de la mémoire, et en faisant réfléchir sur son l'auto-formation. La découverte des cartes et la construction d un nouveau paysage autoformatif par les memoires ludiques des différentes phases de la vie, a fait apparaître la propriété ludopoètique de l autoterriotalité, au même temps qui a enrégistré la construction ontologique dans sa corporéité

Práticas de cidadania em narrativas de professores de ciências: trabalho coletivo de ensino e de aprendizagem

Esta investigação teve como contexto o município de Altamira, situado na região oeste do Estado do Pará. Foi realizada com professores de ciências de escolas públicas do ensino fundamental e teve como propósitos: i) identificar elementos presentes no fazer pedagógico de professores que afirmam vincular sua prática docente à aprendizagem para a formação da cidadania dos alunos; ii) compreender as razões que levam os educadores a desenvolver atividades com tal perspectiva. Trata-se de uma pesquisa qualitativa, na modalidade narrativa, utilizando como instrumento investigativo entrevista semi-estruturada na coleta dos relatos orais das professoras investigadas. As participantes da pesquisa revelam um ensino de ciências conectado com as demais áreas do conhecimento buscando apoio e participação da comunidade escolar. Destacam-se elementos da prática docente, tais como: i) Prática docente reflexiva, favorecendo a auto formação do profissional, por reconhecer seu fazer pedagógico como um ato de conhecimento e compreender sua importância política, ética, estética e também epistemológica. ii) Participação ativa em fóruns escolares, nos quais se planejam várias ações do processo educativo por meio de discussões de diferentes argumentos e troca de experiências. iii) Construção e execução de projetos temáticos que potencializam a alfabetização científica, por meio da exploração de ambientes socioambientais de ensino e de aprendizagem favorecendo a interação escola comunidade e a compreensão pública da ciência. iv) Democratização do espaço escolar, cuja utilização pela comunidade ocorre de diversas formas, dentre as quais se destacam a participação e socialização de atividades de ciências como: feira de ciências, jardinagem e horta escolar. v) Parceria, que se estabelece como meio de partilha de responsabilidade no ato de formar e de educar com o objetivo de estabelecer o diálogo entre a ciência e o senso comum. vi) Atitude como conteúdo expressa nas práticas dos professores que levam os alunos a tomadas de consciência e mudança de postura. vii) Solidariedade, um agir local que pode tomar maior dimensão, ato de reconhecer o outro como semelhante. viii) O cuidado no trato pedagógico, buscando caminhos para educar para além de sua disciplina ciências. Uma prática pedagógica estruturada sob a visão de ser humano que se indaga a respeito de seu lugar no mundo. Estes elementos permitiram a construção de três princípios educacionais pautados no aprender, uma vez que a intenção, da maioria das entrevistadas, ao ensinar ciências, se situa em dar condições intelectuais aos alunos para compreender processos naturais e tecnológicos presentes no mundo que os rodeia e comportarem-se nele como atores responsáveis.

Interação verbal e ensino de uma competência discursiva oral em turmas de francês língua estrangeira de Macapá

Neste trabalho, apoiamo-nos num corpus oriundo de uma pesquisa realizada em turmas de Francês Língua Estrangeira (FLE) de Macapá e num material teórico construído a partir da leitura de pesquisadores como Vygotsky, Bakhtin, Kramsch, Vion, Kerbrat-Orecchioni, Castellotti, Gajo, Grandcolas, Arditty, Vasseur, Mondada, Pekarek Doehler e Cicurel, com o objetivo de investigar a função das interações verbais no ensino-aprendizagem de uma competência comunicativa oral nessas turmas. Mais especificamente, objetivamos a: 1) Descrever as metodologias de ensino da produção oral (PO) realizadas em turmas de FLE em Macapá; 2) Analisar as interações verbais que se realizam entre professor e aluno e dos alunos entre si, em turmas de FLE macapaenses; 3) Apresentar sugestões para uma prática de ensino do discurso que valorize as interações verbais e os contextos sociointeracionistas. Nossas investigações visam a responder às seguintes perguntas de pesquisa: 1) Que lugar ocupa o ensino da PO nas turmas macapaenses de FLE?; 2) Qual o papel da língua materna (LM) no processo de aquisição do discurso em língua estrangeira (LE)?; 3) Em que medida uma metodologia fundamentada na Teoria Sociointeracionista do Ensino de Línguas poderia beneficiar o ensino da PO em turmas de FLE?; 4) Como criar um ambiente favorável ao desenvolvimento de uma competência de PO em turmas de FLE? A fim de identificarmos as causas das dificuldades conversacionais dos estudantes, entrevistamos alunos e professores e observamos, gravamos e transcrevemos aulas em três escolas. Posteriormente, tratamos os dados orientando-nos principalmente pela abordagem sociointeracionista do ensino de línguas em contexto escolar (Vygotsky, Bakhtin) e pelo interacionismo discursivo apresentado por Kramsch (1991). Abordamos temas ligados ao ensino-aprendizagem de línguas, tais como as aquisições linguageiras mediadas pelas interações sociais realizadas em sala de aula ou fora dela, o tratamento do erro, o papel da língua materna no processo de apropriação discursiva e os diálogos dos manuais enquanto ferramentas para a construção de uma competência conversacional. Ao final, propomos uma reflexão sobre a (auto) formação do ensinante interativo e, a partir das sugestões de Kramsch, uma tipologia de atividades discursivas, com o intuito de mostrar de forma mais concreta como favorecer a construção de uma competência de PO em LE em turmas de FLE.

Mediação biográfica: propostas para a formação docente

This work aims at studying the biographical mediation taken as the progress of people in formation process who develop a biographical work on their own experiences with the help of a former (PASSEGGI, 2006, 2011). The research was carried out on a curricular component from Curso de Formação Inicial e Continuada (initial and continuous process of formation of teachers) with teachers from public schools developed by Instituto Federal de Educação do Rio Grande do Norte (IFRN/ Ipanguaçu). The target audience featured diversity of professionals and experiences of formation. The general objective studied the potentials of procedures and devices used to mediate the reflection about the necessary knowledge to teaching practice based on their own experiences (auto-biographical) and the experience from the others (hetero-biographical). The study tried to respond to the following questions: how do teachers in formation relate themselves to the knowledge from experience? What procedures and devices contribute on the teachers‟ formation on the three different dimensions of biographical mediation (initiatory, maieutic, hermeneutics)? How to provide the auto-formation and hetero-formation? The theories and methods of this work are based on studies and researches that place the person in formation in the center of investigation and formation and analyze their reflective, re-inventive and self-re-inventive capacity. (FREIRE, 1987, 1996, 2001, 2011; JOSSO, 2008, 2010, 2012; DELORY-MONBERGER, 2006, 2008, 2012; CHARLLOT, 2000; CATANI, 2001; PASSEGGI, 2008; 2010; 2011; 2012). We selected six teachers who participate entirely on the meetings of the program. They discussed on the study topics, shared narrations that integrate their formation and the themes related to the course. The empirical material is composed by the narrations of the six participants and hearing boards done by themselves at the moment of the narration sharing process. The analysis followed three steps: a) the path of the program and the procedures of biographical mediation; b) the relations former/teacher on the three dimensions of biographical mediation; c) the hearing board as a device of biographical mediation. We concluded that the procedures and devices used for biographical mediation made possible specific learnings that are sources for the practice of initial and continuous teachers‟ formation, as well as for the formation of the former-researcher about the work with autobiographical narrations. Thus, it allow the co-investment of participants into the process of auto-formation and hetero-formation.

Runx2 overexpression in bone marrow stromal cells accelerates bone formation in critically-sized femoral defects

The repair of large non-unions in long bones remains a significant clinical problem due to high failure rates and limited tissue availability for auto- and allografts. Many cell-based strategies for healing bone defects deliver bone marrow stromal cells to the defect site to take advantage of the inherent osteogenic capacity of this cell type. However, many factors, including donor age and ex vivo expansion of the cells, cause bone marrow stromal cells to lose their differentiation ability. To overcome these limitations, we have genetically engineered bone marrow stromal cells to constitutively overexpress the osteoblast specific transcription factor Runx2. In the present study, we examined Runx2-modified bone marrow stromal cells, delivered via poly(caprolactone) scaffolds loaded with type I collagen meshes, in critically-sized segmental defects in rats compared to unmodified cells, cell-free scaffolds and empty defects. Runx2 expression in bone marrow stromal cells accelerated healing of critically-sized defects compared to unmodified bone marrow stromal cells and defects receiving cell-free treatments. These findings provide an accelerated method for healing large bone defects which may reduce recovery time and the need for external fixation of critically-sized defects.

Auto-ignition based synthesis of Y2O3 for photo- and thermo-luminescent applications

We present a simple route for synthesis of Y2O3 for both photoluminescent (PL) and thermoluminescent (TL) applications. We show that by simply switching the fuel from ethylene di-amine tetracetic acid (EDTA) to its disodium derivative (Na-2-EDTA), we obtain a better photoluminescent material. On the other hand, use of EDTA aids in formation of Y2O3 which is a better thermoluminescent material. In both cases pure cubic nano-Y2O3 is obtained. For both the material systems, structural characterization, photoluminescence, thermoluminescence, and absorbance spectra are reported and analyzed. Use of EDTA results in nano Y2O3 with crystallite size similar to 10 nm. Crystallinity improves, and crystallite size is larger (similar to 30 nm) when Na-2-EDTA is used. TL response of Y2O3 nanophosphors prepared by both fuels is examined using UV radiation. Samples prepared with EDTA show well resolved glow curve at 140 degrees C, while samples prepared with Na-2-EDTA shows a glow curve at 155 degrees C. Effect of UV exposure time on TL characteristics is investigated. The TL kinetic parameters are also calculated using glow curve shape method. Results indicate that the TL behavior of both the samples follow a second order kinetic model. (C) 2013 Elsevier B.V. All rights reserved.

One pot auto-ignition based synthesis of novel Sr2CeO4: Ho3+ nanophosphor for photoluminescent applications

Ho3+ (0.25-7 mol%) doped Sr2CeO4 nanophosphors were synthesized by solution combustion method using urea as fuel. The structural properties of the nanophosphors were investigated by powder X-ray diffraction studies (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. UV-Visible and photoluminescence (PL) spectroscopic techniques were used for analysing the optical properties of the nanoparticles. PXRD and TEM results revealed the formation of Sr2CeO4: Ho3+ nanocrystalline particles with orthorhombic crystal structure. From the UV-Vis studies the optical band gap energy found to decrease from 5.9 to 5.74 eV with increase in dopant concentration. The PL spectra exhibit the broad excitation band from 200 to 400 nm which concurs well with the commercial near UV LED. The PL spectra vary with the dopant content due to energy transfer from the host to the activator. In this present work we demonstrate that color tuning of phosphor can be achieved by merely varying the Ho3+ ions concentration. The CIE and CCT chromaticity coordinates suggests Sr2CeO4: Ho3+ nanophosphors may be potentially applicable as promising single - phased phosphors for lighting applications. (C) 2015 Elsevier B.V. All rights reserved.

New tools for self-organised pattern formation

Position-dependent gene expression is a critical aspect of the development and behaviour of multicellular organisms. It requires a complex series of interactions to occur between different cell types in addition to intracellular signalling cascades. We used Escherichia coli to study the properties of an artificial signalling system at the interface between two expanding cell populations. We genetically engineered one population to produce a diffusible acyl-homoserine lactone (AHL) signal, and another population to respond to it. Our experiments demonstrate how such a signal can be used to reproducibly generate simple visible patterns with high accuracy in swimming agar. The producing and responding cassettes of two such signalling systems can be linked to produce a symmetric interface for bidirectional communication that can be used to visualise molecular logic. Intracellular feedback between these two cassettes would then create a framework for self-organised patterning of higher complexity. Adapting the experiments of Basu et al. (Basu et al., 2005) using cell motility, rather than a differential response to AHL concentrations as a way to define zones of response, we noted how the interaction of sender and receiver cell populations on a swimming plate could lead to complex pattern formation. Equipping highly motile strains such as E. coli MC1000 with AHL-mediated auto-inducing systems based on Vibrio fischeri luxI/luxR and Pseudomonas aeruginosa lasI/lasR cassettes would allow the amplification of a response to an AHL signal and its propagation. We designed and synthesised codon-optimised auto-inducing luxI/R and lasI/R cassettes as optimal gene expression is crucial for the generation of robust patterns. We still have to complete and test the entire genetic circuitry, although by modelling the system we were able to demonstrate its feasibility. © 2007 The Institution of Engineering and Technology.

Influence of turbulence-chemistry interaction for n-heptane spray combustion under diesel engine conditions with emphasis on soot formation and oxidation

The influence of the turbulence-chemistry interaction (TCI) for n-heptane sprays under diesel engine conditions has been investigated by means of computational fluid dynamics (CFD) simulations. The conditional moment closure approach, which has been previously validated thoroughly for such flows, and the homogeneous reactor (i.e. no turbulent combustion model) approach have been compared, in view of the recent resurgence of the latter approaches for diesel engine CFD. Experimental data available from a constant-volume combustion chamber have been used for model validation purposes for a broad range of conditions including variations in ambient oxygen (8-21% by vol.), ambient temperature (900 and 1000 K) and ambient density (14.8 and 30 kg/m3). The results from both numerical approaches have been compared to the experimental values of ignition delay (ID), flame lift-off length (LOL), and soot volume fraction distributions. TCI was found to have a weak influence on ignition delay for the conditions simulated, attributed to the low values of the scalar dissipation relative to the critical value above which auto-ignition does not occur. In contrast, the flame LOL was considerably affected, in particular at low oxygen concentrations. Quasi-steady soot formation was similar; however, pronounced differences in soot oxidation behaviour are reported. The differences were further emphasised for a case with short injection duration: in such conditions, TCI was found to play a major role concerning the soot oxidation behaviour because of the importance of soot-oxidiser structure in mixture fraction space. Neglecting TCI leads to a strong over-estimation of soot oxidation after the end of injection. The results suggest that for some engines, and for some phenomena, the neglect of turbulent fluctuations may lead to predictions of acceptable engineering accuracy, but that a proper turbulent combustion model is needed for more reliable results. © 2014 Taylor & Francis.

Interactions spatiales et auto-organisation des végétations semi-arides

Les recherches récapitulées dans cette thèse de doctorat ont porté sur les causes de l’organisation spatiale des végétations périodiques. Ces structures paysagères aux motifs réguliers, tachetés, tigrés ou labyrinthiques, d’échelle décamétrique à hectométrique, couvrant des étendues considérables sur au moins trois continents, constituent un cas d’école dans l’étude des processus endogènes présidant à l’hétérogénéité du couvert végétal. Ces structures prennent place sur un substrat homogène, mis à part la rétroaction du couvert lui-même, et sont marquées par des écotones abrupts et la persistance d’une proportion considérable de sol nu. Plusieurs modèles ont mis en avant l’existence possible d’un phénomène d’auto-organisation du couvert, qui verrait une structure d’ensemble émerger des interactions locales entre individus. Ces modèles se basent sur le jeu simultané de la consommation de la ressource (compétition) et de l’amélioration de l’un ou l’autre des éléments du bilan de la même ressource par le couvert (facilitation). La condition à l’existence d’une structure d’ensemble spatialement périodique et stable réside dans une différence entre la portée de la compétition (plus grande) et celle de la facilitation. L’apparition de ces structures est modulée par le taux de croissance biologique, qui est le reflet des contraintes extérieures telles que l’aridité, le pâturage ou la coupe de bois. Le modus operandi des interactions spatiales supposées entre individus reste largement à préciser.

Nos recherches ont été menées au sud-ouest de la République du Niger, à l’intérieur et dans les environs du parc Régional du W. Trois axes ont été explorés :(i) Une étude de la dépendance spatiale entre la structure de la végétation (biovolumes cartographiés) et les paramètres du milieu abiotique (relief, sol), sur base d’analyses spectrales et cross-spectrales par transformée de Fourier (1D et 2D). (ii) Une étude diachronique (1956, 1975 et 1996) à large échelle (3000 km²) de l’influence de l’aridité et des pressions d’origine anthropique sur l’auto-organisation des végétations périodiques, basée sur la caractérisation de la structure spatiale des paysages sur photos aériennes via la transformée de Fourier en 2D. (iii) Trois études portant sur les interactions spatiales entre individus :En premier lieu, via l’excavation des systèmes racinaires (air pulsé) ;Ensuite, par un suivi spatio-temporel du bilan hydrique du sol (blocs de gypse) ;Enfin, via le marquage de la ressource par du deutérium.

Nous avons ainsi pu établir que les végétations périodiques constituent bien un mode d’auto-organisation pouvant survenir sur substrat homogène et modulé par les contraintes climatiques et anthropiques. Un ajustement rapide entre l’organisation des végétations périodiques et le climat a pu être montrée en zone protégée. La superficie et l’organisation des végétations périodiques y ont tour à tour progressé et régressé en fonction d’épisodes secs ou humides. Par contre, en dehors de l’aire protégée, la possibilité d’une restauration du couvert semble fortement liée au taux d’exploitation des ressources végétales. Ces résultats ont d’importantes implications quant à la compréhension des interactions entre climat et écosystèmes et à l’évaluation de leurs capacités de charge. La caractérisation de la structure spatiale des végétations arides, notamment par la transformée de Fourier d’images HR, devrait être généralisée comme outil de monitoring de l’état de ces écosystèmes. Nos études portant sur les modes d’interactions spatiales ont permis de confirmer l’existence d’une facilitation à courte portée du couvert végétal sur la ressource. Cependant, cette facilitation ne semble pas s’exercer sur le terme du bilan hydrique traditionnellement avancé, à savoir l’infiltration, mais plutôt sur le taux d’évaporation (deux fois moindre à l’ombre des canopées). Ce mécanisme exclut l’existence de transferts diffusifs souterrains entre sols nu et fourrés. Des transferts inverses semblent d’ailleurs montrés par le marquage isotopique. L’étude du bilan hydrique et la cartographie du micro-relief, ainsi que la profondeur fortement réduite de la zone d’exploitation racinaire, jettent de sérieux doutes quant au rôle communément admis des transferts d’eau par ruissellement/diffusion de surface en tant que processus clé dans la compétition à distance entre les plantes. L’alternative réside dans l’existence d’une compétition racinaire de portée supérieure aux canopées. Cette hypothèse trouve une confirmation tant par les rhizosphères excavées, superficielles et étendues, que dans le marquage isotopique, montrant des contaminations d’arbustes situés à plus de 15 m de la zone d’apport. De même, l’étude du bilan hydrique met en évidence les influences simultanées et contradictoires (facilitation/compétition) des ligneux sur l’évapotranspiration.

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This PhD thesis gathers results of a research dealing with the causes of the spatial organisation of periodic vegetations. These landscape structures, featuring regular spotted, labyrinthine or banded patterns of decametric to hectometric scale, and extending over considerable areas on at least three continents, constitute a perfect study case to approach endogenous processes leading to vegetation heterogeneities. These patterns occur over homogeneous substratum, except for vegetation’s own feedbacks, and are marked by sharp ecotones and the persistence of a considerable amount of bare soil. A number of models suggested a possible case of self-organized patterning, in which the general structure would emerge from local interactions between individuals. Those models rest on the interplay of competitive and facilitative effects, relating to soil water consumption and to soil water budget enhancement by vegetation. A general necessary condition for pattern formation to occur is that negative interactions (competition) have a larger range than positive interactions (facilitation). Moreover, all models agree with the idea that patterning occurs when vegetation growth decreases, for instance as a result of reduced water availability, domestic grazing or wood cutting, therefore viewing patterns as a self-organised response to environmental constraints. However the modus operandi of the spatial interactions between individual plants remains largely to be specified.

We carried out a field research in South-West Niger, within and around the W Regional Park. Three research lines were explored: (i) The study of the spatial dependency between the vegetation pattern (mapped biovolumes) and the factors of the abiotic environment (soil, relief), on the basis of spectral and cross-spectral analyses with Fourier transform (1D and 2D). (ii) A broad scale diachronic study (1956, 1975, 1996) of the influence of aridity and human induced pressures on the vegetation self-patterning, based on the characterisation of patterns on high resolution remote sensing data via 2D Fourier transform. (iii) Three different approaches of the spatial interactions between individuals: via root systems excavation with pulsed air; via the monitoring in space and time of the soil water budget (gypsum blocks method); and via water resource labelling with deuterated water.

We could establish that periodic vegetations are indeed the result of a self-organisation process, occurring in homogeneous substratum conditions and modulated by climate and human constraints. A rapid adjustment between vegetation patterning and climate could be observed in protected zones. The area and patterning of the periodic vegetations successively progressed and regressed, following drier or wetter climate conditions. On the other hand, outside protected areas, the restoration ability of vegetation appeared to depend on the degree of vegetation resource exploitation. These results have important implications regarding the study of vegetation-climate interactions and the evaluation of ecosystems’ carrying capacities. Spatial pattern characterisation in arid vegetations using Fourier transform of HR remote sensing data should be generalised for the monitoring of those ecosystems. Our studies dealing with spatial interaction mechanisms confirmed the existence of a short range facilitation of the cover on water resource. However, this facilitation does not seem to act through the commonly accepted infiltration component, but rather on the evaporative rate (twice less within thickets). This mechanism excludes underground diffusive transfers between bare ground and vegetation. Inverse transfers were even shown by deuterium labelling. Water budget study and micro-elevation mapping, along with consistent soil shallowness, together cast serious doubts on the traditional mechanism of run-off/diffusion of surface water as a key process of the long range competition between plants. An alternative explanation lies in long range root competition. This hypothesis find support as well in the excavated root systems, shallow and wide, as in isotopic labelling, showing contaminations of shrubs located up to 15 m of the irrigated area. Water budget study also evidenced simultaneous contradictory effects (facilitation/competition) of shrubs on evapotranspiration.

Modulation of intracellular calcium homeostasis blocks autophagosome formation

Cellular stress responses often involve elevation of cytosolic calcium levels, and this has been suggested to stimulate autophagy. Here, however, we demonstrated that agents that alter intracellular calcium ion homeostasis and induce ER stress-the calcium ionophore A23187 and the sarco/endoplasmic reticulum Ca (2+)-ATPase inhibitor thapsigargin (TG)-potently inhibit autophagy. This anti-autophagic effect occurred under both nutrient-rich and amino acid starvation conditions, and was reflected by a strong reduction in autophagic degradation of long-lived proteins. Furthermore, we found that the calcium-modulating agents inhibited autophagosome biogenesis at a step after the acquisition of WIPI1, but prior to the closure of the autophagosome. The latter was evident from the virtually complete inability of A23187- or TG-treated cells to sequester cytosolic lactate dehydrogenase. Moreover, we observed a decrease in both the number and size of starvation-induced EGFP-LC3 puncta as well as reduced numbers of mRFP-LC3 puncta in a tandem fluorescent mRFP-EGFP-LC3 cell line. The anti-autophagic effect of A23187 and TG was independent of ER stress, as chemical or siRNA-mediated inhibition of the unfolded protein response did not alter the ability of the calcium modulators to block autophagy. Finally, and remarkably, we found that the anti-autophagic activity of the calcium modulators did not require sustained or bulk changes in cytosolic calcium levels. In conclusion, we propose that local perturbations in intracellular calcium levels can exert inhibitory effects on autophagy at the stage of autophagosome expansion and closure.

Tyrosine phosphorylation and dephosphorylation in Burkholderia cenocepacia affect biofilm formation, growth under nutritional deprivation, and pathogenicity

Burkholderia cenocepacia, a member of the B. cepacia complex (Bcc), is an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. Tyrosine phosphorylation has emerged as an important post-translational modification modulating the physiology and pathogenicity of Bcc bacteria. Here, we investigated the predicted bacterial tyrosine kinases BCAM1331 and BceF, and the low molecular weight protein tyrosine phosphatases BCAM0208, BceD and BCAL2200 of B. cenocepacia K56-2. We show that BCAM1331, BceF, BCAM0208 and BceD contributed to biofilm formation, while BCAL2200 was required for growth in nutrient-limited conditions. Multiple deletions of either tyrosine kinase or low molecular weight protein tyrosine phosphatases genes resulted in attenuation of B. cenocepacia intramacrophage survival and reduced pathogenicity in the Galleria mellonella larvae infection model. Experimental evidence indicates that BCAM1331 displays a reduced
tyrosine autophosphorylation activity compared to BceF. Using the artificial substrate p-nitrophenyl phosphate, the phosphatase activity of the three low molecular weight protein tyrosine phosphatases demonstrated similar kinetic parameters. However, only BCAM0208 and BceD could dephosphorylate BceF. Further, BCAL2200 becomes tyrosine phosphorylated in vivo and catalyzes its auto-dephosphorylation. Together, our data suggest that despite having similar biochemical activities low molecular weight protein tyrosine phosphatases and tyrosine kinases have both overlapping and specific roles in the physiology of B. cenocepacia.