59 resultados para Hunger strike
Resumo:
Memory is essential to adjust behaviour according to past experience. In societies where animals interact on numerous occasions, memory of previous social interactions may help optimise investment in competition. How long information about the resource holding potential and motivation to compete of conspecifics is retained depends on how fast the value of this information fades, but also on the cost and benefit of retaining information. Information retention has never been investigated in the context of interactions prevailing within the family and more specifically sibling competition. In the absence of parents, barn owl (Tyto alba) nestlings vocally compete for priority of access to the next indivisible food item brought by a parent. The finding that owlets eavesdrop on vocal interactions between siblings to adjust investment in vocalization once competing with them suggests that they memorize siblings' vocal interactions. Playback experiments showed that owlets take into account the past siblings' vocal performance that signals hunger for at least 15 min, but only if the performance was witnessed during a sufficiently long period of time (30 min). Moreover, using natural vocal exchanges in another set of individuals, we showed that sibling signalling was no more taken into account after a few minutes. This suggests that young barn owls need to continuously display their motivation to trigger siblings' withdrawal from the current competition. Repeating a vocal display may ensure its honesty. Studying the extent to which individuals retain past information is important to understand how individuals adjust their competitive investment over resources.
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The results of a coupled, in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb study on zircon and geochemical characterization of the Eastern Cordilleran intrusives of Peru reveal 1.15 Ga of intermittent magmatism along central Western Amazonia, the Earth's oldest active open continental margin. The eastern Peruvian batholiths are volumetrically dominated by plutonism related to the assembly and breakup of Pangea during the Paleozoic-Mesozoic transition. A Carboniferous-Permian (340-285 Ma) continental arc is identified along the regional orogenic strike from the Ecuadorian border (6 degrees S) to the inferred inboard extension of the Arequipa-Antofalla terrane in southern Peru (14 degrees S). Widespread crustal extension and thinning, which affected western Gondwana throughout the Permian and Triassic resulted in the intrusion of the late- to post-tectonic La Merced-San Ramon-type anatectites dated between 275 and 220 Ma, while the emplacement of the southern Cordillera de Carabaya peraluminous granitoids in the Late Triassic to Early Jurassic (220-190 Ma) represents, temporally and regionally, a separate tectonomagmatic event likely related to resuturing of the Arequipa-Antofalla block. Volcano-plutonic complexes and stocks associated with the onset of the present Andean cycle define a compositionally bimodal alkaline suite and cluster between 180 and 170 Ma. A volumetrically minor intrusive pulse of Oligocene age (ca. 30 Ma) is detected near the southwestern Cordilleran border with the Altiplano. Both post-Gondwanide (30-170 Ma), and Precambrian plutonism (691-1123 Ma) are restricted to isolated occurrences spatially comprising less than 15% of the Eastern Cordillera intrusives. Only one remnant of a Late Ordovician intrusive belt is recognized in the Cuzco batholith (446.5 +/- 9.7 Ma) indicating that the Famatinian arc system previously identified in Peru along the north-central Eastern Cordillera and the coastal Arequipa-Antofalla terrane also existed inboard of this parautochthonous crustal fragment. Hitherto unknown occurrences of late Mesoproterozoic and middle Neoproterozoic granitoids from the south-central cordilleran segment define magmatic events at 691 +/- 13 Ma, 751 +/- 8 Ma, 985 +/- 14 Ma, and 1071-1123 +/- 23 Ma that are broadly coeval with the Braziliano and Grenville-Sunsas orogenies, respectively. Our data suggest the existence of a continuous orogenic belt in excess of 3500 km along Western Amazonia during the formation of Rodinia, its ``early'' fragmentation prior to 690 Ma, and support a model of reaccretion of the Paracas-Arequipa-Antofalla terrane to western Gondwana in the Early Ordovician with subsequent detachment of the Paracas segment in form of the Mexican Oaxaquia microcontinent in Middle Ordovician. A tectonomagmatic model involving slab detachment, followed by underplating of cratonic margin by asthenospheric mantle is proposed for the genesis of the volumetrically dominant Late Paleozoic to early Mesozoic Peruvian Cordilleran batholiths.
Resumo:
The traditional obesity treatments have proven to be ineffective in the long-term. The presence of eating disorders frequently explains this phenomena. Eating educational and behavioral aspects must be addressed in a practical way so that patients could gradually become aware of their behavior towards food as well as internal sensations associated with hunger, satiety, craving and pleasure. Finally, the link between emotions and compulsive eating behaviors during and between meals is an essential aspect that the general practitioner can help the patient to understand. A specialized psychological treatment can then be considered when the patient shows sufficient motivation and consciousness.
Resumo:
Summary This dissertation explores how stakeholder dialogue influences corporate processes, and speculates about the potential of this phenomenon - particularly with actors, like non-governmental organizations (NGOs) and other representatives of civil society, which have received growing attention against a backdrop of increasing globalisation and which have often been cast in an adversarial light by firms - as a source of teaming and a spark for innovation in the firm. The study is set within the context of the introduction of genetically-modified organisms (GMOs) in Europe. Its significance lies in the fact that scientific developments and new technologies are being generated at an unprecedented rate in an era where civil society is becoming more informed, more reflexive, and more active in facilitating or blocking such new developments, which could have the potential to trigger widespread changes in economies, attitudes, and lifestyles, and address global problems like poverty, hunger, climate change, and environmental degradation. In the 1990s, companies using biotechnology to develop and offer novel products began to experience increasing pressure from civil society to disclose information about the risks associated with the use of biotechnology and GMOs, in particular. Although no harmful effects for humans or the environment have been factually demonstrated even to date (2008), this technology remains highly-contested and its introduction in Europe catalysed major companies to invest significant financial and human resources in stakeholder dialogue. A relatively new phenomenon at the time, with little theoretical backing, dialogue was seen to reflect a move towards greater engagement with stakeholders, commonly defined as those "individuals or groups with which. business interacts who have a 'stake', or vested interest in the firm" (Carroll, 1993:22) with whom firms are seen to be inextricably embedded (Andriof & Waddock, 2002). Regarding the organisation of this dissertation, Chapter 1 (Introduction) describes the context of the study, elaborates its significance for academics and business practitioners as an empirical work embedded in a sector at the heart of the debate on corporate social responsibility (CSR). Chapter 2 (Literature Review) traces the roots and evolution of CSR, drawing on Stakeholder Theory, Institutional Theory, Resource Dependence Theory, and Organisational Learning to establish what has already been developed in the literature regarding the stakeholder concept, motivations for engagement with stakeholders, the corporate response to external constituencies, and outcomes for the firm in terms of organisational learning and change. I used this review of the literature to guide my inquiry and to develop the key constructs through which I viewed the empirical data that was gathered. In this respect, concepts related to how the firm views itself (as a victim, follower, leader), how stakeholders are viewed (as a source of pressure and/or threat; as an asset: current and future), corporate responses (in the form of buffering, bridging, boundary redefinition), and types of organisational teaming (single-loop, double-loop, triple-loop) and change (first order, second order, third order) were particularly important in building the key constructs of the conceptual model that emerged from the analysis of the data. Chapter 3 (Methodology) describes the methodology that was used to conduct the study, affirms the appropriateness of the case study method in addressing the research question, and describes the procedures for collecting and analysing the data. Data collection took place in two phases -extending from August 1999 to October 2000, and from May to December 2001, which functioned as `snapshots' in time of the three companies under study. The data was systematically analysed and coded using ATLAS/ti, a qualitative data analysis tool, which enabled me to sort, organise, and reduce the data into a manageable form. Chapter 4 (Data Analysis) contains the three cases that were developed (anonymised as Pioneer, Helvetica, and Viking). Each case is presented in its entirety (constituting a `within case' analysis), followed by a 'cross-case' analysis, backed up by extensive verbatim evidence. Chapter 5 presents the research findings, outlines the study's limitations, describes managerial implications, and offers suggestions for where more research could elaborate the conceptual model developed through this study, as well as suggestions for additional research in areas where managerial implications were outlined. References and Appendices are included at the end. This dissertation results in the construction and description of a conceptual model, grounded in the empirical data and tied to existing literature, which portrays a set of elements and relationships deemed important for understanding the impact of stakeholder engagement for firms in terms of organisational learning and change. This model suggests that corporate perceptions about the nature of stakeholder influence the perceived value of stakeholder contributions. When stakeholders are primarily viewed as a source of pressure or threat, firms tend to adopt a reactive/defensive posture in an effort to manage stakeholders and protect the firm from sources of outside pressure -behaviour consistent with Resource Dependence Theory, which suggests that firms try to get control over extemal threats by focussing on the relevant stakeholders on whom they depend for critical resources, and try to reverse the control potentially exerted by extemal constituencies by trying to influence and manipulate these valuable stakeholders. In situations where stakeholders are viewed as a current strategic asset, firms tend to adopt a proactive/offensive posture in an effort to tap stakeholder contributions and connect the organisation to its environment - behaviour consistent with Institutional Theory, which suggests that firms try to ensure the continuing license to operate by internalising external expectations. In instances where stakeholders are viewed as a source of future value, firms tend to adopt an interactive/innovative posture in an effort to reduce or widen the embedded system and bring stakeholders into systems of innovation and feedback -behaviour consistent with the literature on Organisational Learning, which suggests that firms can learn how to optimize their performance as they develop systems and structures that are more adaptable and responsive to change The conceptual model moreover suggests that the perceived value of stakeholder contribution drives corporate aims for engagement, which can be usefully categorised as dialogue intentions spanning a continuum running from low-level to high-level to very-high level. This study suggests that activities aimed at disarming critical stakeholders (`manipulation') providing guidance and correcting misinformation (`education'), being transparent about corporate activities and policies (`information'), alleviating stakeholder concerns (`placation'), and accessing stakeholder opinion ('consultation') represent low-level dialogue intentions and are experienced by stakeholders as asymmetrical, persuasive, compliance-gaining activities that are not in line with `true' dialogue. This study also finds evidence that activities aimed at redistributing power ('partnership'), involving stakeholders in internal corporate processes (`participation'), and demonstrating corporate responsibility (`stewardship') reflect high-level dialogue intentions. This study additionally finds evidence that building and sustaining high-quality, trusted relationships which can meaningfully influence organisational policies incline a firm towards the type of interactive, proactive processes that underpin the development of sustainable corporate strategies. Dialogue intentions are related to type of corporate response: low-level intentions can lead to buffering strategies; high-level intentions can underpin bridging strategies; very high-level intentions can incline a firm towards boundary redefinition. The nature of corporate response (which encapsulates a firm's posture towards stakeholders, demonstrated by the level of dialogue intention and the firm's strategy for dealing with stakeholders) favours the type of learning and change experienced by the organisation. This study indicates that buffering strategies, where the firm attempts to protect itself against external influences and cant' out its existing strategy, typically lead to single-loop learning, whereby the firm teams how to perform better within its existing paradigm and at most, improves the performance of the established system - an outcome associated with first-order change. Bridging responses, where the firm adapts organisational activities to meet external expectations, typically leads a firm to acquire new behavioural capacities characteristic of double-loop learning, whereby insights and understanding are uncovered that are fundamentally different from existing knowledge and where stakeholders are brought into problem-solving conversations that enable them to influence corporate decision-making to address shortcomings in the system - an outcome associated with second-order change. Boundary redefinition suggests that the firm engages in triple-loop learning, where the firm changes relations with stakeholders in profound ways, considers problems from a whole-system perspective, examining the deep structures that sustain the system, producing innovation to address chronic problems and develop new opportunities - an outcome associated with third-order change. This study supports earlier theoretical and empirical studies {e.g. Weick's (1979, 1985) work on self-enactment; Maitlis & Lawrence's (2007) and Maitlis' (2005) work and Weick et al's (2005) work on sensegiving and sensemaking in organisations; Brickson's (2005, 2007) and Scott & Lane's (2000) work on organisational identity orientation}, which indicate that corporate self-perception is a key underlying factor driving the dynamics of organisational teaming and change. Such theorizing has important implications for managerial practice; namely, that a company which perceives itself as a 'victim' may be highly inclined to view stakeholders as a source of negative influence, and would therefore be potentially unable to benefit from the positive influence of engagement. Such a selfperception can blind the firm from seeing stakeholders in a more positive, contributing light, which suggests that such firms may not be inclined to embrace external sources of innovation and teaming, as they are focussed on protecting the firm against disturbing environmental influences (through buffering), and remain more likely to perform better within an existing paradigm (single-loop teaming). By contrast, a company that perceives itself as a 'leader' may be highly inclined to view stakeholders as a source of positive influence. On the downside, such a firm might have difficulty distinguishing when stakeholder contributions are less pertinent as it is deliberately more open to elements in operating environment (including stakeholders) as potential sources of learning and change, as the firm is oriented towards creating space for fundamental change (through boundary redefinition), opening issues to entirely new ways of thinking and addressing issues from whole-system perspective. A significant implication of this study is that potentially only those companies who see themselves as a leader are ultimately able to tap the innovation potential of stakeholder dialogue.
Resumo:
Animals can compete for resources by displaying various acoustic signals that may differentially affect the outcome of competition. We propose the hypothesis that the most efficient signal to deter opponents should be the one that most honestly reveals motivation to compete. We tested this hypothesis in the barn owl (Tyto alba) in which nestlings produce more calls of longer duration than siblings to compete for priority access to the indivisible prey item their parents will deliver next. Because nestlings increase call rate to a larger extent than call duration when they become hungrier, call rate would signal more accurately hunger level. This leads us to propose three predictions. First, a high number of calls should be more efficient in deterring siblings to compete than long calls. Second, the rate at which an individual calls should be more sensitive to variation in the intensity of the sibling vocal competition than the duration of its calls. Third, call rate should influence competitors' vocalization for a longer period of time than call duration. To test these three predictions we performed playback experiments by broadcasting to singleton nestlings calls of varying durations and at different rates. According to the first prediction, singleton nestlings became less vocal to a larger extent when we broadcasted more calls compared to longer calls. In line with the second prediction, nestlings reduced vocalization rate to a larger extent than call duration when we broadcasted more or longer calls. Finally, call rate had a longer influence on opponent's vocal behavior than call duration. Young animals thus actively and differentially use multiple signaling components to compete with their siblings over parental resources.
Resumo:
Swiss clinical practice guidelines for skin cancer in organ transplant recipients Transplant patients have increased over the last decades. As a consequence of long-term immunosuppression, skin cancer, in particular squamous cell carcinoma (SCC), has become an important problem. Screening and education of potential organ transplant recipients (OTRs) regarding prevention of sun damage and early recognition of skin cancer are important before transplantation. Once transplanted, OTRs should be seen yearly by a dermatologist to ensure compliance with sun avoidance as well as for treatment of precancerosis and SCC. Early removal is the best treatment for SCC. Reduction of immunosuppression, switch to mTOR inhibitors and chemoprevention with acitretin may reduce the incidence of SCC. The dermatological follow-up of OTRs should be integrated into a comprehensive post-transplant management strategy.
Resumo:
The gold mineralization of the Hutti Mine is hosted by nine parallel, N - S trending, steeply dipping, 2 - 10 m wide shear zones, that transect Archaean amphibolites. The shear zones were formed after peak metamorphism during retrograde ductile D, shearing in the lower amphibolite facies. They were reactivated in the lower to mid greenschist facies by brittle-ductile D-3 shearing and intense quartz veining. The development of a S-2-S-3 crenulation cleavage facilitates the discrimination between the two deformation events and contemporaneous alteration and gold mineralization. Ductile D, shearing is associated with a pervasively developed distal chlorite - sed cite alteration assemblage in the outer parts of the shear zones and the proximal biotite-plagioclase alteration in the center of the shear zones. D3 is characterized by development of the inner chlorite-K-feldspar alteration, which forms a centimeter-scale alteration halo surrounding the laminated quartz veins and replaces earlier biotite along S-3. The average size of the laminated vein systems is 30-50 m along strike as well as down-dip and 2-6 m in width. Mass balance calculations suggest strong metasomatic changes for the proximal biotite-plagioclase alteration yielding mass and volume increase of ca. 16% and 12%, respectively. The calculated mass and volume changes of the distal chlorite-sericite alteration (ca. 11%, ca. 8%) are lower. The decrease in 6180 values of the whole rock from around 7.5 parts per thousand for the host rocks to 6-7 parts per thousand for the distal chlorite-sericite and the proximal biotite-plagioclase alteration and around 5 parts per thousand for the inner chlorite-K-feldspar alteration suggests hydrothermal alteration during two-stage deformation and fluid flow. The ductile D-2 deformation in the lower amphibolite facies has provided grain scale porosities by microfracturing. The pervasive, steady-state fluid flow resulted in a disseminated style of gold-sulfide mineralization and a penetrative alteration of the host rocks. Alternating ductile and brittle D3 deformation during lower to mid greenschist facies conditions followed the fault-valve process. Ductile creep in the shear zones resulted in a low permeability environment leading to fluid pressure build-up. Strongly episodic fluid advection and mass transfer was controlled by repeated seismic fracturing during the formation of laminated quartz(-gold) veins. The limitation of quartz veins to the extent of earlier shear zones indicate the importance of preexisting anisotropies for fault-valve action and economic gold mineralization. (C) 2003 Elsevier B.V. All rights reserved.
Resumo:
RESUME: Une zone tectonique large et complexe, connue sous le nom de ligne des Centovalli, traverse le secteur des Alpes Centrales compris entre Domodossola et Locarno. Cette région, formée par le Val Vigezzo et la vallée des Centovalli, constitue la terminaison méridionale du dôme Lepontin et représente une portion de la zone des racines des nappes alpines. Elle fait partie dune grande et complexe zone de cisaillement, en partie associée à des phénomènes hydrothermaux dâge alpin (<20 Ma), qui comprend le système tectonique Insubrien et celui du Simplon. Le Val Vigezzo et les Centovalli constituent un vrai carrefour entre les principaux accidents tectoniques des Alpes ainsi qu'une zone de juxtaposition du socle Sudalpin avec la zone des racines de lAustroalpin et du Pennique. Les phases de déformation et les structures géologiques qui peuvent être étudiées s'étalent sur une période comprise entre environ 35 Ma et l'actuel. Létude détaillée de terrain a mis en évidence la présence de nombreuses roches et structures de déformation de type ductile et cassant tels que des mylonites, des cataclasites, des pseudotachylites, des kakirites, des failles minéralisées, des gouges de faille et des plis. Sur le terrain on a pu distinguer au moins quatre générations de plis liés aux différentes phases de déformation. Le nombre et la complexité de ces structures indiquent une histoire très compliquée, selon plusieurs étapes distinctes, parfois liées, voire même superposées. Une partie de ces structures de déformation affectent aussi les dépôts sédimentaires dâge quaternaire, notamment des limons et des sables lacustres. Ces sédiments constituent les restes d'un bassin lacustre attribué à l'époque interglaciaire Riss/Würm (éemien, 67.000-120.000 ans) et ils affleurent dans la partie centrale de la zone étudiée, à l'Est de la plaine de Santa Maria Maggiore. Ces sédiments montrent en leur sein toute une série de structures de déformation tels que des plans de faille inverses, des structures conjuguées de raccourcissement et des véritables plis. Ces failles et ces plis représenteraient les évidences de surface dune déformation probablement active en époque quaternaire. Une autre formation rocheuse a retenu tout notre attention; il s'agit d'un corps de brèches péridotitiques monogéniques qui affleure en discontinuité le long du versant méridional et le long du fond de la vallée Vigezzo sur environ 20 km. Ces brèches se posent indifféremment sur le socle (unités Finero, Orselina) ou sur les sédiments lacustres. Elles sont traversées par des plans de failles qui développent des véritables stries de faille et des gouges de faille; lorientation de ces plans est la même que celle affectant les failles à gouges du socle. La genèse de cette brèche est liée à l'altération et au modelage glacier (rock-glaciers) d'une brèche tectonique originelle qui borde la partie externe du Corps de Finero. Les structures de déformation de cette brèche, pareillement à celles des sédiments lacustres, ont été considérées comme les évidences de surface d'une tectonique quaternaire active dans la région. La dernière phase de déformation cassante qui affecte cette région peut donc être considérée comme active en époque quaternaire. Une vue densemble de la région étudiée nous permet de reconnaître à léchelle régionale une zone de cisaillement complexe orientée E-W, parallèlement à laxe de la vallée Centovalli-Val Vigezzo. Les données de terrain, indiquent que cette zone de cisaillement débute sous conditions ductiles et évolue en plusieurs étapes jusquà des conditions de failles cassantes de surface. La reconstruction de l'évolution géodynamique de la région a permis de définir trois étapes distinctes qui marquent le passage, de ce secteur de socle cristallin, de conditions P-T profondes à des conditions de surface. Dans ce contexte, on a reconnu trois phases principales de déformation à léchelle régionale qui caractérisent ces trois étapes. La phase la plus ancienne est constituée par des mylonites en faciès amphibolite, associées à des mouvements de cisaillement dextre, qui sont ensuite remplacés par des mylonites en faciès schistes verts et des plis rétrovergentes liés au rétrocharriage des nappes alpines. Une deuxième étape est identifiée par le développement dune phase hydrothermale liée à un système de failles extensives et décrochantes dextres à direction principale E-W, NE-SW et NW-SE. Leur caractérisation minéralogique a permis la mise en évidence des phases cristallines de néoformation liées à cet événement constituées par : K-feldspath (microcline), chlorites (Fe+Mg), épidotes, prehnite, zéolites (laumontite), sphène, calcite. Dans ce contexte, pour obtenir une meilleure caractérisation de cet événement hydrothermal on a utilisé des géothermomètres sur chlorites, sensible aussi à la pression et a la a(H2O), qui ont donné des valeurs descendantes comprises entre 450-200°C. Les derniers mouvements sont mis en évidence par le développement dune série de plans majeurs de failles à gouge, qui forment une structure en sigmoïdes dépaisseur kilométrique reconnaissable à léchelle de la vallée et caractérisée par des mouvements transpressifs avec une composante décrochante dextre toujours importante. Cette phase de déformation forme un système conjugué de failles avec direction moyenne E-W qui coupent la zone des racines des nappes alpines, la zone du Canavese et le corps ultramafique de Finero. Ce système se déroule de manière subparallèle à l'axe de la vallée le long de plusieurs dizaines de kilomètres. Une analyse complète et détaillée des gouges de faille par XRD a montré que la fraction argileuse (<2 µm) de ces gouges contient une partie de néoformation très importante constituée par, des illites, des chlorites et des interstratifiés de type illite/smectite ou chlorite/smectite. Des datations avec méthode K-Ar sur ces illites ont donné des valeurs comprises entre 12 et 4 Ma qui représentent l'âge de cette dernière déformation cassante. L'application de la méthode de la cristallinité de l'illite (C.I.) a permis d'évaluer les conditions thermiques qui caractérisent le déroulement de cette dernière phase tectonique qui se produit sous conditions de température caractéristiques de l'anchizone et de la diagenèse. L'ensemble des structures de déformation qu'on vient de décrire s'insère parfaitement dans le contexte de convergence oblique entre la plaque adriatique et celle européenne qui à produit l'orogène alpin. On peut considérer les structures tectoniques du Val Vigezzo-Centovalli comme l'expression d'une zone majeure de cisaillement "Simplo-Insubrienne". L'empilement structural et les structures tectoniques affleurantes dans la région sont le résultat de l'interaction entre un régime tectonique transpressif et un régime transtensif. Ces deux champs de tension sont antagonistes entre eux mais sont reliés, de toute façon, à une seule phase décrochante dextre principale, due à une convergence oblique entre deux plaques. À l'échelle de l'évolution géodynamique on peut distinguer différentes étapes au cours desquelles les structures de ces deux régimes tectoniques interagissent en manière différente. En accord avec les données géophysiques et les reconstructions paléodynamiques prises dans la littérature on considère que la ligne Rhône-Simplon-Centovalli représente l'évidence de surface de la suture majeure profonde entre la plaque Adriatique et celle Européenne. Les vitesses de soulèvement qui ont été calculées dans cette étude pour cette région des Alpes donnent une valeur moyenne de 0.8 mm/a qui est tout à fait comparable avec les données proposées par la littérature sur cette zone. La zone Val Vigezzo-Centovalli peut être donc considérée comme un carrefour géologique où se croisent différentes phases tectoniques qui représentent les évidences de surface d'une suture profonde majeure entre deux plaques dans un contexte de collision continentale. ABSTRACT: A wide and complex tectonic zone known as Centovalli line, crosses the Central Alps sector between Domodossola and Locarno. This area, formed by the Vigezzo Valley and Centovalli valley, constitutes the southernmost termination of the Lepontin dome and represents a portion of the alpine nappes root zone. It belongs to a large and complex shear-zone, partly associated with hydrothermal phenomena of alpine age (<20 My), which includes the Insubric Line and the Simplon fault zone. Vigezzo Valley and Centovalli constitute a real crossroads between the mains alpines tectonics lines as well as a zone of juxtaposition of the Southalpine basement with the Austroalpin and Pennique root zone. The deformation phases and the geological structures that can be studied between approximately 35 My and the present. The detailed field study showed the presence of many brittle and ductile deformation structures and fault rocks such as mylonites, cataclasites, pseudotachylites, kakirites, mineralized faults, fault gouges and folds. In the field we could distinguish at least four folds generations related to the various deformation phases. The number and the complexity of these structures indicate a very complicated history, comprising several different stages, that sometimes are related and even superimposed. Part of these deformation structures affect also the sedimentary deposits of quaternary age, in particular the silts and sands lake deposit. These sediments constitute the remainders of a lake basin ascribed to the interglacial Riss/Würm (Eemien, 67.000-120.000 years) and outcroping in the central part of the studied area, in the Eastern part of Santa Maria Maggiore plain. These sediments show a whole series of deformation structures such as inverse fault planes, combined shortening structures and true folds. These faults and folds would represent the surface evidence of a probably active tectonic deformation in quaternary time. Another rock formation attracted all our attention. It is a body of monogenic peridotite breccia which outcrops in discontinuity along the southernmost slope and the bottom of the Vigezzo valley on approximately 20 km. This breccia lies indifferently on the basement (Finero and Orselina units) or on the lake sediments. They are crossed by fault planes which developed slikenside and fault gouges whose orientation is the same of the faults gouges in the alpine basement. This breccia results from the weathering and the surface modelling of an original tectonic breccia which borders the external part of Finero peridotite body. This breccia deformation structures, like those of the lake sediments, were regarded as the surface interaction of active quaternary tectonics in the area. So the last brittle deformation phases which affects this area seems to be actives in quaternary time. Theoverall picture of the studied area on a regional scale enables us to point out a complex shear-zone directed E-W, parallel to the axis of the Centovalli and Vigezzo Valley. The field analysis indicates that this shear-zone began under ductile conditions and evolved in several stages to brittle faulting under surface conditions. The analysis of the geodynamic evolution of the area allows to define three different stages which mark the transition of this alpine basement root zone, from deep P-T conditions to P-T surface conditions. In this context on regional scale three principal deformation phases, which characterize these three stages can be distinguished. The oldest phase consisted of the amphibolitie facies mylonites, associated to dextral strikeslip movements. They are then replaced by green-schists facies mylonites and backfolds related to the backthrusting of the alpines nappes. A second episode is caracterized by the development of an hydrothermal phase bound to an extensive fault and dextral strike-slip fault system, with E-W, NW-SE and SE-NW principal directionsThe principal neoformed mineral phases related to this event are: K-feldspar (microcline), chlorites (Fe+Mg), epidotes prehnite, zéolites (laumontite), sphene and calcite. In this context, to obtain a better characterization of this hydrothermal event, we have used an chlorite geothermometer, sensitive also to the pressure and has the a(H2O), which gave downward values ranging between 450-200°C. The last movements are caracterized by the development of important gouge fault plans, which form a sigmoid structure of kilometric thickness which is recognizable at the valley scale, and is characterized by transpressive movements always with a significant dextral strike-slip component. This deformation phase forms a combined faults system with an average E-W direction, which cuts trough the alpine root zone, the Canavese zone and the Finero ultramafic body. This fault system takes place subparallel to the axis of the valley over several tens of kilometers. A complete and detailed XRD analysis of the gouges fault showed that the clay fraction (<2µm) contains a very significant neo-formation of illite, chlorites and mixed layered clays such as illite/smectite or chlorite/smectite. The K-Ar datings of the illite fraction <2µm gave values ranging between 12 and 4 My and the illite fraction <0.2µm gave more recents values until to 2,4-0 My.This values represent the age of this last brittle deformation. The application of the illite crystallinity method (C.I.) allowed evaluating the thermal conditions which characterize this tectonic phase that occured under temperature conditions of the anchizone and diagenesis. The whole set of deformation structures which we just described, perfectly fit the context of oblique convergence between the Adriatic and the European plate that produced the alpine orogen. We can regard the Vigezzo valley and Centovalli tectonic structures as the expression of a major "Simplo-Insubric" shear-zone. Structural stacking and tectonic structures that outcrop in the studied area, are the result of the interaction between a transpressive and a transtensve tectonic phases. These two tension fields are antagonistic but they are also connected, in any event, with only one principal dextral strike-slip movement, caused by an oblique convergence between two plates. On the geodynamic evolution scale we can distinguish various stages during which these two tectonic structures fields interact in various ways. In agreement with the geophysical data and the paleodynamic recostructions taken in the literature we considers that the Rhone-Simplon-Centovalli line are the surface feature of the major collision between the Adriatique and the European plate at depth. The uplift speeds we calculated in this study for this Alpine area give an average value of 0.8 mm/a, which is in good agreement with the data suggested by the literature on this zone. TheVigezzo Valley and Centovalli zone can therefore be regarded as a geological crossroad where various tectonic phases are superimposed. They represent the evidences of a major and deeper suture between two plates in a continental collision context.
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L?objectif de ce travail de recherche était de décrypter l?évolution géodynamique de la Péninsule de Biga (Turquie du N-O), à travers l?analyse de deux régions géologiques peu connues, le mélange de Çetmi et la zone d?Ezine (i.e. le Groupe d?Ezine et l?ophiolite de Denizgören). Une étude complète et détaillée de terrain (cartographie et échantillonnage) ainsi qu?une approche multidisciplinaire (sédimentologie de faciès, pétrographie sédimentaire et magmatique, micropaléontologie, datations absolues, géochimie sur roche totale, cristallinité de l?illite) ont permis d?obtenir de nouveaux éléments d?information sur la région considérée. ? Le mélange de Çetmi, de type mélange d?accrétion, affleure au nord et au sud de la Péninsule de Biga ; les principaux résultats de son étude peuvent se résumer comme suit: - Son aspect structural actuel (nature des contacts, organisation tectonique) est principalement dû au régime extensif Tertiaire présent dans la région. - Il est constitué de blocs de différentes natures : rares calcaires Scythien-Ladinien dans le faciès Han Bulog, blocs hectométriques de calcaires d?âge Norien-Rhaetien de rampe carbonatée, nombreux blocs décamétriques de radiolarites rouges d?âge Bajocien- Aptien, blocs/écailles de roches magmatiques de type spilites (basaltes à andésite), ayant des signatures géochimiques d?arcs ou intra-plaques. - La matrice du mélange est constituée d?une association greywacke-argilites dont l?âge Albien inférieur à moyen a été déterminé par palynologie. - L?activité du mélange s?est terminée avant le Cénomanien (discordance Cénomanienne au sommet du mélange, pas de bloc plus jeune que la matrice). - Du point de vue de ses corrélations latérales, le mélange de Çetmi partage plus de traits communs avec les mélanges se trouvant dans les nappes allochtones du Rhodope (nord de la Grèce et sud-ouest de la Bulgarie) qu?avec ceux de la suture Izmir-Ankara (Turquie); il apparaît finalement que sa mise en place s?est faite dans une logique balkanique (chevauchements vers le nord d?âge anté-Cénomanien). ? Le Groupe d?Ezine et l?ophiolite sus-jacente de Denizgören affleurent dans la partie ouest de la Péninsule de Biga. Le Groupe d?Ezine est une épaisse séquence sédimentaire continue (3000 m), subdivisée en trois formations, caractérisée chacune par un type de sédimentation spécifique, relatif à un environnement de dépôt particulier. De par ses caractéristiques (grande épaisseur, variations latérales de faciès et d?épaisseur dans les formations, érosion de matériel provenant de l?amont du bassin), le groupe d?Ezine est interprétée comme un dépôt syn-rift d?âge Permien moyen-Trias inférieur. Il pourrait représenter une partie de la future marge passive sud Rhodopienne à la suite de l?ouverture de l?océan Maliac/Méliata. L?ophiolite de Denizgören sus-jacente repose sur le Groupe d?Ezine par l?intermédiaire d?une semelle métamorphique à gradient inverse, du faciès amphibolite à schiste vert. L?âge du faciès amphibolite suggère une initiation de l?obduction au Barrémien (125 Ma, âge Ar/Ar); cet âge est unique dans le domaine égéen, mais il peut là aussi être relié à une logique balkanique, sur la base de comparaison avec le domaine Rhodopien. ? Toutes les unités précédentes (mélange de Çetmi, Groupe d?Ezine et ophiolite de Denizgören) ont passivement subi trois phases extensives pendant le Tertiaire. Dans la région d?Ezine et du mélange nord, les micaschistes HP sous-jacents ont été exhumés avant l?Eocène moyen. Dans le cas du mélange sud, cette exhumation Eocene est en partie enregistrée dans les mylonites séparant le mélange du dôme métamorphique sous-jacent du Kazda?. Le mélange sud est dans tous les cas fortement érodé à la suite de la double surrection du dôme du Kazda?, près de la lim ite Oligocène/Miocene et pendant le Plio- Quaternaire. Dans le premier cas, ce soulèvement est caractérisé par le développement d?une faille de détachement à faible pendage, qui contrôle à la fois l?exhumation du massif, et la formation d?un bassin sédimentaire syntectonique, de type bassin supradétachement; quant à la phase extensive la plus récente, elle est contrôlée par le jeu de failles normales à forts pendages qui remanient l?ensemble des structures héritées, et dictent la géomorphologie actuelle de la région. ? Il est possible de proposer un scénario pour l?évolution géodynamique de la Péninsule de Biga, basé sur l?ensemble des résultats précédents et sur les données de la géologie régionale ; ses points principaux sont: - La Péninsule de Biga fait partie de la marge Rhodopienne. - Le Groupe d?Ezine est un témoin de la marge passive nord Maliac/Méliata. - L?ophiolite de Denizgören et le mélange de Çetmi ont été mis en place tous deux vers le nord sur la marge précédente, respectivement au Barrémien et à l?Albien terminal- Cénomanien inférieur. - Une forte composante décrochante durant l?emplacement est suggérée par la préservation de fragments de la marge passive et l?absence de métamorphisme dans la plaque inférieure. - Tous les évènements précédents ont été largement affectés par le régime d?extension Tertiaire.<br/><br/>The purpose of this study is to unravel the geodynamic evolution of the Biga Peninsula (NW Turkey) through the detailed study of two poorly known areas, the Çetmi mélange and the Ezine zone (i.e. the Ezine Group and the Denizgören ophiolite). The methodology was based on a detailed field work and a multidisciplinary approach. ? The accretion-related Çetmi mélange is mainly cropping out north and south of the Biga Peninsula; the main results of its study can be summarized as follows: -Its present-day structural aspect (type of contacts, tectonic organisation) is largely inherited from the Tertiary extensional regime in the region. -It is made of blocks of various natures: Han Bulog limestones with a Scythian to Ladinian age, common carbonate ramp Norian-Rhaetian limestones (biggest blocks of the mélange), red radolarite with a Bajocian to Aptian age; the most common lithology of the mélange is made by block/slices of spilitic magmatic rocks (basalt to andesite); they have volcanic arc or within plate basalt geochemical signatures. -The matrix of the mélange is made of a greywacke-shale association of Early-Middle Albian age. - The mélange stopped its activity before the Cenomanian (no younger blocks than the matrix, and Cenomanian unconformity). - If compared to the regional geology, the Çetmi mélange shares some characteristics with the Izmir-Ankara mélanges (less), and with the mélanges from allochthonous nappes found in eastern Rhodope (more); it appears finally that its emplacement is related to a Balkanic logic (ante-Cenomanian northward thrusting). ? The Ezine Group and the overlying Denizgören ophiolite are cropping out in the western part of the Biga Peninsula. The Ezine Group is a thick sedimentary sequence interpreted as a syn-rift deposit of Middle Permian-Early Triassic age. It represents a part of the south Rhodopian passive margin, following the opening of the Maliac/Meliata oceanic domain. The Denizgören ophiolite has been emplaced northward on the Ezine Group in the Barremian (125 Ma, age of the amphibolitic sole); this age is unique in the Aegean domain, but here again, it may be related to a Balkan logic. ? All the previous units (Çetmi mélange, Ezine Group and Denizgören ophiolite) have passively suffered two extensional regimes during the Tertiary. In the Ezine and northern Çetmi mélange area, the underlying HP Çamlýca micaschists were exhumed before the Middle Eocene. As for the southern mélange, it was strongly eroded following the Late Oligocene to Quaternary uplift of the underlying Kazda? Massif. This uplift was characterized by the development of a low-angle detachment fault controlling a part of the exhumation, as well as the development of a supra-detachment basin. ? Based on the previous results, and on the data from the regional geology, one can propose a scenario for the geodynamic evolution of the Biga Peninsula. Its key points are:- The Biga Peninsula is belonging to the Rhodope margin. - The Ezine Group is a remnant of the northern Maliac/Meliata passive margin. - Both the Denizgören ophiolite and the Çetmi mélange have been emplaced northward on the previous margin, respectively in the Barremian and in the Late Albian-Early Cenomanian times. - The preservation of the remnants of the Rhodope margin, as well as the absence of metamorphism in the lower plate suggest a strong strike-slip component during the emplacements. - All the previous events are (at least) partly obliterated by the Tertiary extensional regime.<br/><br/>Le géologue est comme un «historien» de la Terre, qui porte un intérêt particulier à l?étude du passé de notre planète; ce dernier, très ancien, se mesure en dizaines ou centaines de millions d?années (Ma). Or le visage de la terre a constamment évolué au cours des ces millions d?années écoulés, car les plaques (continentales et océaniques) qui composent son enveloppe superficielle ne restent pas immobiles, mais se déplacent continuellement à sa surface, à une vitesse de l?ordre du cm/an (théorie de la tectonique des plaques); c?est ainsi, par exemple, que des océans naissent, grandissent, puis finissent par se refermer. On appelle sutures océaniques, les zones, aujourd?hui sur la terre ferme, où l?on retrouve les restes d?océans disparus. Ces sutures sont caractérisées par deux associations distinctes de roches, que l?on appelle les mélanges et les ophiolites; ces mélanges et ophiolites sont donc les témoins de l?activité passée d?un océan aujourd?hui refermé. L?équipe de recherche dans laquelle ce travail à été réalisé s?intéresse à un vaste domaine océanique fossile: l?océan Néotéthys. Cet océan, de plusieurs milliers de kilomètres de large, séparait alors l?Europe et l?Asie au nord, de l?Afrique, l?Inde et l?Australie au sud. De cet océan, il n?en subsiste aujourd?hui qu?une infime partie, qui se confond avec notre mer Méditerranée actuelle. Or, tout comme l?océan Pacifique est bordé de mers plus étroites (Mer de Chine, du Japon, etc?), l?océan Néotéthys était bordé au nord de mers marginales. C?est dans ce cadre que s?est inscrit mon travail de thèse, puisqu?il a consisté en l?étude d?une suture océanique (mélange plus ophiolite), témoin d?une des mers qui bordait l?océan Néotéthys sur sa marge nord. L?objectif était de préciser de quelle suture il s?agissait, puis de déterminer quand et comment elle avait fonctionné (i.e son évolution géologique). Les roches qui composent cette suture affleurent aujourd?hui en Turquie nord occidentale dans la Péninsule de Biga. Au nord et au sud de la péninsule se trouvent les zones géologique du mélange de Çetmi, et à l?ouest, le Groupe d?Ezine et l?ophiolite susjacente, dite ophiolite de Denizgören. Une étude complète et détaillée de terrain (cartographie, échantillonnage), suivie de diverses analyses en laboratoire (détermination de leur âge, de leur condition de formation, etc?), ont permis d?aboutir aux principaux résultats suivants : - Mise en évidence dans le mélange de Çetmi des témoins (1) de l?océan Lycien disparu (ancienne mer marginale de la Néotéthys), et (2) de la marge continentale qui le bordait au nord. - Fin de l?activité du mélange de Çetmi il y a environ 105 Ma (Albien). - Le mélange de Çetmi est difficilement corrélable dans le temps avec les unités semblables affleurant dans la région d?étude (unicité du mélange), ce qui implique des conditions particulière de formation. - L?ophiolite de Denizgören est un morceau d?océan Lycien posé sur un reste préservé de sa marge continentale nord. - Cette dernière est représentée sur le terrain par une succession de roches caractéristiques, le Groupe d?Ezine. Celui-ci est lui-même un témoin de l?ouverture d?un océan marginal de la Néotethys antérieur au Lycien, l?océan Maliac, qui s?est ouvert il y a 245 Ma (Permien-Trias). - La mise en place de l?ophiolite de Denizgören sur le Groupe d?Ezine (125 Ma, Barrémien) est antérieure à la mise en place du mélange de Çetmi. - Il apparaît que ces deux mises en place sont contemporaines de la formation de la chaîne des Balkans, terminée avant le Cénomanien (100 Ma). - L?évolution dans le temps des objets précédents (océans, marges continentales) montre de grands mouvements latéraux est-ouest entre ces objets (translation). Ce qui implique que les roches que l?on retrouve aujourd?hui sur un transect nord-sud ne l?étaient pas nécessairement auparavant. - Enfin, il s?avère que le mélange de Çetmi, l?ophiolite de Denizgören, et le Groupe d?Ezine ont subi par la suite des déformations extensives importantes qui ont considérablement perturbé le schéma post-mise en place.
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We describe how an electromagnetic wave after a lightning strike affected a university hospital, including the communication shutdown that followed, the way it was handled, and the lessons learned from this incident.
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The effects of footwear and inclination on running biomechanics over short intervals are well documented. Although recognized that exercise duration can impact running biomechanics, it remains unclear how biomechanics change over time when running in minimalist shoes and on slopes. Our aims were to describe these biomechanical changes during a 50-minute run and compare them to those observed in standard shoes. Thirteen trained recreational male runners ran 50 minutes at 65% of their maximal aerobic velocity on a treadmill, once in minimalist shoes and once in standard shoes, 1 week apart in a random order. The 50-minute trial was divided into 5-minute segments of running at 0%, +5%, and -5% of treadmill incline sequentially. Data were collected using photocells, high-speed video cameras, and plantar-pressure insoles. At 0% incline, runners exhibited reduced leg stiffness and plantar flexion angles at foot strike and lower plantar pressure at the forefoot and toes in minimalist shoes from minute 34 of the protocol onward. However, only reduced plantar pressure at the toes was observed in standard shoes. Overall, similar biomechanical changes with increased exercise time were observed on the uphill and downhill inclines. The results might be due to the unfamiliarity of subjects to running in minimalist shoes.
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Cutaneous melanoma is the most deadly cutaneous neoplasm. In order to guide treatment decisions and follow-up of melanoma patients, guidelines for the management of melanoma in Switzerland were inaugurated in 2001 and revised in 2006 and 2016. Recent data on surgical and medical treatments from randomised trials necessitated modification of the treatment and follow-up recommendations.