1,720,971 research outputs found
Effect of Vitamin K3 on plasma membrane-bound H+-ATPase and reductase activities in plants
No full textVitamin K-like compds. are widely diffused in plants, but their role and function are still partially unknown. Vitamin K1 - phylloquinone - is largely present in thylakoid membranes as electron carrier inside the PSI redox chain. More recently, it has been found that Vitamins K1 and K3 may also affect the plasmalemma-bound H+-ATPase and reductase activities. In this article we report the effects of Vitamin K3 treatment on the above activities in three different conditions: in the presence of Vitamin K3; after the addn. of Vitamin K3 to the hydroponic soln.; after sonication of plasma membrane in the presence of Vitamin K3 in the soln. Results showed that Vitamin K3 was able to improve both plasmalemma H+-ATPase and reductase activities at a concn. that is very well tolerated by the whole plant. Our findings support the hypothesis that Vitamin K is involved in plasmalemma activities of both mono and dicotyledonous plants
The pre-Alpine tectonic history of the Austroalpine continental basement in the Valpelline unit (Western Italian Alps)
Full text linkThe Valpelline unit is a large slice of continental crust constituting
the Austroalpine Dent Blanche nappe (NW Italy). The pre-Alpine evolution
of this unit holds important clues about the Palaeozoic crustal
structure at the northern margin of the Adria continent, about the
history of rifting in the Alpine region, and thus about the
thermomechanical conditions that preceded the Alpine convergent
evolution. Several stages of the deformation history and of partial
re-equilibration were identified, combining meso-and micro-structural
analyses with thermobarometry. Reconstructed pre-Alpine P-T-t-d paths
demonstrate that the Valpelline unit experienced an early stage at
pressures between 4.5 and 6.5 kbar followed by migmatite formation. A
subsequent stage reached amphibolite to granulite facies conditions.
This stage was associated with the development of the most penetrative
fabrics affecting all of the Valpelline lithotypes. The pre-Alpine
evolution ended with a weak deformation associated with a local
mineral-chemical re-equilibration under greenschist facies conditions at
approximate to 4 kbar and T < 450 degrees C. A Permo-Mesozoic
lithospheric extension is thought to be responsible for asthenosphere
upwelling, thereby causing high temperature metamorphism at medium
pressure and widespread partial melting, which led to upper crustal
magmatic activity
Local shape similarity and mean-shift curvature for deformable surface mapping of anatomical structures
No full textThis paper reports a novel method for deformable registration of digital anatomical surfaces. The method capitalizes upon the iterative local affine iterative closest point (ICP) approach that applies an affine transformation per surface vertex along with a regularization constraint to force neighboring surface vertices to undergo similar transformations. More robust vertex correspondence with respect to simple closest point was obtained by exploiting local shape similarity metrics, which includes vertex distance, surface normal, and local curvature. The local curvature was mean shifted at run-time, during the iterative optimization, to make the point correspondence process less dependent upon the surface noise and resolution. The experimental validation was performed on three surface datasets (femur, hemi-pelvic bone, and liver). The registration results showed that the proposed method outperforms, across all the three surface datasets (rmse: 0.19 mm, 0.30mm, 0.61 mm), global affine ICP (rmse: 2.89mm, 3.95mm, and 8.30 mm), local affine ICP (rmse: 0.31 mm, 1.61 mm, and 1.63 mm) and coherent point drift (rmse: 1.99 mm, 2.39 mm, and 4.78 mm) methods. As a whole, the mean-shifted curvature increased the registration accuracy by about 20%
Carboniferous to Permian migmatite formation in the Austroalpine continental basement (Valpelline unit) and its implication for the onset of tha Alpine convergence
No full textThe tectonometamorphic evolution of the Sesia–Dent Blanche nappes (internal Western Alps) : review and synthesis
No full textThis study reviews and synthesizes the present knowledge on the Sesia–Dent Blanche nappes, the highest tectonic elements in the Western Alps (Switzerland and Italy), which comprise pieces of pre-Alpine basement and Mesozoic cover. All of the available data are integrated in a crustal-scale kinematic model with the aim to reconstruct the Alpine tectono-metamorphic evolution of the Sesia–Dent Blanche nappes. Although major uncertainties remain in the pre-Alpine geometry, the basement and cover sequences of the Sesia–Dent Blanche nappes are seen as part of a thinned continental crust derived from the Adriatic margin. The earliest stages of the Alpine evolution are interpreted as recording late Cretaceous subduction of the Adria-derived Sesia–Dent Blanche nappes below the South-Alpine domain. During this subduction, several sheets of crustal material were stacked and separated by shear zones that rework remnants of their Mesozoic cover. The recently described Roisan-Cignana Shear Zone of the Dent Blanche Tectonic System represents such a shear zone, indicating that the Sesia–Dent Blanche nappes represent a stack of several individual nappes. During the subsequent subduction of the Piemonte–Liguria Ocean large-scale folding of the nappe stack (including the Roisan-Cignana Shear Zone) took place under greenschist facies conditions, which indicates partial exhumation of the Dent Blanche Tectonic System. The entrance of the Briançonnais micro-continent within the subduction zone led to a drastic change in the deformation pattern of the Alpine belt, with rapid exhumation of the eclogite-facies ophiolite-bearing units and thrust propagation towards the foreland. Slab breakoff probably was responsible for allowing partial melting in the mantle and Oligocene intrusions into the most internal parts of the Sesia–Dent Blanche nappes. Finally, indentation of the Adriatic plate into the orogenic wedge resulted in the formation of the Vanzone back-fold, which marks the end of the pervasive ductile deformation within the Sesia–Dent Blanche nappes during the earliest Miocene
Geometry and kinematics of the Roisan-Cignana Shear Zone, and the orogenic evolution of the Dent Blanche Tectonic System (Western Alps)
No full textThe Dent Blanche Tectonic System (DBTS) is a composite thrust sheet derived from the previously thinned passive Adriatic continental margin. A kilometric high-strain zone, the Roisan-Cignana Shear Zone (RCSZ) defines the major tectonic boundary within the DBTS and separates it into two subunits, the Dent Blanche s.s. nappe to the northwest and the Mont Mary nappe to the southeast. Within this shear zone, tectonic slices of Mesozoic and pre-Alpine meta-sediments became amalgamated with continental basement rocks of the Adriatic margin. The occurrence of high pressure assemblages along the contact between these tectonic slices indicates that the amalgamation occurred prior to or during the subduction process, at an early stage of the Alpine orogenic cycle. Detailed mapping, petrographic and structural analysis show that the Roisan-Cignana Shear Zone results from several superimposed Alpine structural and metamorphic stages. Subduction of the continental fragments is recorded by blueschist-facies deformation, whereas the Alpine collision is reflected by a greenschist facies overprint associated with the development of large-scale open folds. The post-nappe evolution comprises the development of low-angle brittle faults, followed by large-scale folding (Vanzone phase) and finally brittle extensional faults. The RCSZ shows that fragments of continental crust had been torn off the passive continental margin prior to continental collision, thus recording the entire history of the orogenic cycle. The role of preceding Permo-Triassic lithospheric thinning, Jurassic rifting, and ablative subduction processes in controlling the removal of crustal fragments from the reactivated passive continental margin is discussed. Results of this study constrain the temporal sequence of the tectono-metamorphic processes involved in the assembly of the DBTS, but they also show limits on the interpretation. In particular it remains difficult to judge to what extent pre-collisional rifting at the Adriatic continental margin preconditioned the efficiency of convergent processes, i.e. accretion, subduction, and orogenic exhumation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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