Showing papers by "University of Montpellier published in 2000"
TL;DR: In this paper, the authors propose an unusual mode of subduction known as flat subduction, occurring in ∼10% of the world's convergent margins, that can produce the temperature and pressure conditions necessary for fusion of moderately old oceanic crust.
Abstract: Slab melting has been suggested as a likely source of adakitic arc magmas (i.e., andesitic and dacitic magmas strongly depleted in Y and heavy rare earth elements). Existing numerical and petrologic models, however, restrict partial melting to very young (≤ 5 Ma) oceanic crust (typically at 60–80 km depth). Paradoxically, most of the known Pliocene-Quaternary adakite occurrences are related to subduction of 10–45 Ma lithosphere, which should not be able to melt under normal subduction-zone thermal gradients. We propose an unusual mode of subduction known as flat subduction, occurring in ∼10% of the world's convergent margins, that can produce the temperature and pressure conditions necessary for fusion of moderately old oceanic crust. Of the 10 known flat subduction regions worldwide, eight are linked to present or recent (<6 Ma) occurrences of adakitic magmas. Observations from Chile, Ecuador, and Costa Rica suggest a three-stage evolution: (1) steep subduction produces a narrow calc-alkaline arc, typically ∼300 km from the trench, above the asthenospheric wedge; (2) once flat subduction begins, the lower plate travels several hundred kilometers at nearly the same depth, thus remaining in a pressure-temperature window allowing slab melting over this broad distance; and (3) once flat subduction continues for several million years, the asthenospheric wedge disappears, and a volcanic gap results, as in modern-day central Chile or Peru. The proposed hypothesis, which reconciles thermal models with geochemical observations, has broad implications for the study of arc magmatism and for the thermal evolution of convergent margins.
529 citations
TL;DR: The sequence of five NRAMP proteins from A. thaliana demonstrate that AtNramp1 participates in the control of iron homoeostasis in plants and leads to an increase in plant resistance to toxic iron concentration.
Abstract: Nramp genes code for a widely distributed class of proteins involved in a variety of processes, ranging from the control of susceptibility to bacterial infection in mammalian cells and taste behaviour in Drosophila to manganese uptake in yeast. Some of the NRAMP proteins in mammals and in yeast are capable of transporting metal ions, including iron. In plants, iron transport was shown to require a reduction/Fe(II) transport system. In Arabidopsis thaliana this process involves the IRT1 and Fro2 genes. Here we report the sequence of five NRAMP proteins from A. thaliana. Sequence comparison suggests that there are two classes of NRAMP proteins in plants: A. thaliana (At) NRAMP1 and Oriza sativa (Os) NRAMP1 and 3 (two rice isologues) represent one class, and AtNRAMP2-5 and OsNRAMP2 the other. AtNramp1 and OsNramp1 are able to complement the fet3fet4 yeast mutant defective both in low- and high-affinity iron transports, whereas AtNramp2 and OsNramp2 fail to do so. In addition, AtNramp1 transcript, but not AtNramp2 transcript, accumulates in response to iron deficiency in roots but not in leaves. Finally, overexpression of AtNramp1 in transgenic A. thaliana plants leads to an increase in plant resistance to toxic iron concentration. Taken together, these results demonstrate that AtNramp1 participates in the control of iron homoeostasis in plants.
499 citations
TL;DR: The aim of this study was to show that the most widely used models simulating vegetative or reproductive phenology of trees are particular cases of a more general model, which provides a standardized framework for phenological models, which is essential for comparative studies as well as for robust model identification.
464 citations
TL;DR: In this article, a local theory was developed for the property of a distance function being continuously differentiable outside of C on some neighborhood of a point x ∈ C, which is equivalent to the prox-regularity of C at x, a condition on normal vectors that is commonly fulfilled in variational analysis and has the advantage of being verifiable by calculation.
Abstract: Recently Clarke, Stern and Wolenski characterized, in a Hilbert space, the closed subsets C for which the distance function dC is continuously differentiable everywhere on an open “tube” of uniform thickness around C Here a corresponding local theory is developed for the property of dC being continuously differentiable outside of C on some neighborhood of a point x ∈ C This is shown to be equivalent to the prox-regularity of C at x, which is a condition on normal vectors that is commonly fulfilled in variational analysis and has the advantage of being verifiable by calculation Additional characterizations are provided in terms of dC being locally of class C 1+ or such that dC + σ| · |2 is convex around x for some σ > 0 Prox-regularity of C at x corresponds further to the normal cone mapping NC having a hypomonotone truncation around x, and leads to a formula for PC by way of NC The local theory also yields new insights on the global level of the Clarke-Stern-Wolenski results, and on a property of sets introduced by Shapiro, as well as on the concept of sets with positive reach considered by Federer in the finite dimensional setting
401 citations
TL;DR: A spectrophotometric nitroblue tetrazolium NBT reduction assay was used to demonstrate the production of superoxide anions O by haemocytes of the white shrimp Penaeus Oannamei, and it was shown that it is indeed theProduction of O y that was measured.
398 citations
TL;DR: In this paper, an infrared data processing developed to analyse the calorific manifestations accompanying elastoplastic transformation during tensile tests is presented, where surface temperature images are provided by an experimental set-up essentially made of a testing machine coupled with an infrared camera equipped with a home-made numerizer.
376 citations
TL;DR: In this paper, a two-dimensional thermo-mechanical laboratory modelling of continental subduction was performed, which confirmed that the continental crust can be deeply subducted and showed that slab break-off, delamination and tectonic underplating are fundamental events with drastic consequences on the subsequent evolution of the convergent system.
374 citations
TL;DR: Three trypsin inhibitors, from the seeds of the squash Momordica cochinchinensis, have been isolated and purified and it was shown that their polypeptide backbones are cyclic, a structure that has never been described in squash TIs.
Abstract: Three trypsin inhibitors (TIs), from the seeds of the squash Momordica cochinchinensis (MCo), have been isolated and purified using gel filtration, ion exchange chromatography, and reverse-phase HPLC. Their sequences could be determined only after proteolytic cleavages. In the case of MCoTI-I and -II, it was shown that their polypeptide backbones are cyclic, a structure that has never been described in squash TIs. They contain 34 amino acid residues with 3 disulfide bridges and measured molecular masses of 3453.0 and 3480.7, respectively. They are the largest known macrocyclic peptides containing disulfide bridges. Their sequences show strong homology to other squash TIs, suggesting a similar three-dimensional structure and an analogous mechanism of action. A model of MCoTI-II was constructed by analogy to the crystal structure of the complex between bovine trypsin and CMTI-I, indicating that the linker connecting the two termini is flexible and does not impose significant geometrical constraints. This fl...
326 citations
TL;DR: The data indicate that disruption of adhesion to the cell matrix through loss of hamartin may initiate the development of TSC hamartomas and that a Rho-mediated signalling pathway regulating cell adhesion may constitute a rate-limiting step in tumour formation.
Abstract: Loss of the tumour-suppressor gene TSC1 is responsible for hamartoma development in tuberous sclerosis complex (TSC), which renders several organs susceptible to benign tumours. Hamartin, the protein encoded by TSC1, contains a coiled-coil domain and is expressed in most adult tissues, although its function is unknown. Here we show that hamartin interacts with the ezrin-radixin-moesin (ERM) family of actin-binding proteins. Inhibition of hamartin function in cells containing focal adhesions results in loss of adhesion to the cell substrate, whereas overexpression of hamartin in cells lacking focal adhesions results in activation of the small GTP-binding protein Rho, assembly of actin stress fibres and formation of focal adhesions. Interaction of endogenous hamartin with ERM-family proteins is required for activation of Rho by serum or by lysophosphatidic acid (LPA). Our data indicate that disruption of adhesion to the cell matrix through loss of hamartin may initiate the development of TSC hamartomas and that a Rho-mediated signalling pathway regulating cell adhesion may constitute a rate-limiting step in tumour formation.
324 citations
TL;DR: After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective and the epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.
Abstract: Background Patient-controlled analgesia (PCA) with intravenous morphine and patient-controlled epidural analgesia (PCEA), using an opioid either alone or in combination with a local anesthetic, are two major advances in the management of pain after major surgery. However, these techniques have been evaluated poorly in elderly people. This prospective, randomized study compared the effectiveness on postoperative pain and safety of PCEA and PCA after major abdominal surgery in the elderly patient. Methods Seventy patients older than 70 yr of age and undergoing major abdominal surgery were assigned randomly to receive either combined epidural analgesia and general anesthesia followed by postoperative PCEA, using a mixture of 0.125% bupivacaine and sufentanil (PCEA group), or general anesthesia followed by PCA with intravenous morphine (PCA group). Pain intensity was tested three times daily using a visual analog scale. Postoperative evaluation included mental status, cardiorespiratory and gastrointestinal functions, and patient satisfaction scores. Results Pain relief was better at rest (P = 0.001) and after coughing (P = 0.002) in the PCEA group during the 5 postoperative days. Satisfaction scores were better in the PCEA group. Although incidence of delirium was comparable in the PCA and PCEA groups (24% vs. 26%, respectively), mental status was improved on the fourth and fifth postoperative days in the PCEA group. The PCEA group recovered bowel function more quickly than did the PCA group. Cardiopulmonary complications were similar in the two groups. Conclusion After major abdominal surgery in the elderly patient, patient-controlled analgesia, regardless of the route (epidural or parenteral), is effective. The epidural route using local anesthetics and an opioid provides better pain relief and improves mental status and bowel activity.
323 citations
TL;DR: The development of strategies for prophylaxis and control of shrimp diseases could be aided by the establishment of a collaborative network to contribute to progress in basic knowledge of penaeid immunity and to improve efficiency, it appears essential to open this network to complementary research areas related to shrimp pathology, physiology, genetics and environment.
TL;DR: The time has come to focus on fitness dominance levels in the presence and absence of insecticide, according to a general formula forestimating dominance on a scale of 0 to 1.
Abstract: Dominance has been assessed in different ways in insecticide resistance studies, based on three phenotypic traits: the insecticide concentration required to give a particular mortality (DLC), mortality at a particular insecticide dose (DML), and fitness in treated areas (DWT). We propose a general formula for estimating dominance on a scale of 0 to 1 (0 5 complete recessivity and 1 5 complete dominance). DLC ,D ML, and DWT are not directly related and their values depend on genetic background and environmental conditions. We also show that pest management strategies can have the consequence to increase DWT via the selection of dominance modifiers. Studies on resistance to Bacillus thuringiensis toxins provide the ultimate example of the complexity of the definition of the concept of dominance. Almost all studies have focused on calculation of DLC, which provides little information about the efficiency of pest management programs. For instance, one assumption of the high dose/refuge strategy is that Bacillus thuringiensis resistance must be effec- tively recessive (i.e., DML must be close to zero). However, DWT, rather than DML, is relevant to the resistance management strategy. Therefore, we strongly suggest that the time has come to focus on fitness dominance levels in the presence and absence of insecticide.
TL;DR: A review of the xenobiotic resistance literature shows that empirical evidence for this hypothesis is scarce, and it is postulate that such fitness costs can only be fully interpreted in the light of the molecular mutations that might underlie them.
Abstract: The nature and cost of single genes of major effect is one of the longest running controversies in biology. Resistance, whether to xenobiotics or to parasites, is often paraded as an obvious example of a single gene effect that must carry an associated fitness 'cost'. However, a review of the xenobiotic resistance literature shows that empirical evidence for this hypothesis is, in fact, scarce. We postulate that such fitness costs can only be fully interpreted in the light of the molecular mutations that might underlie them. We also derive a theoretical framework both to encompass our current understanding of xenobiotic resistance and to begin to dissect the probable cost of parasite resistance.
TL;DR: In this article, the authors synthesize the effects of fishing on estuaries and coastal waters and review eight process-oriented categories affected by fishing with case studies for each of them: target organisms, non-target organisms, nursery functions, trophic effects, habitat change, reduced water quality, human environment, and potential for local extinctions.
Abstract: Estuaries and associated coastal waters support many essential fisheries, a fact which contributes to their disproportionately high economic value. They are, however, also among the most extensively modified and threatened of aquatic environments. Almost all have been strongly affected by human beings, and fisheries are an integral part of human activities on the coast. We have taken a global perspective in synthesizing the effects of fishing on estuaries and coastal waters. Rather than attempt to cover all regions of the world in detail, we review eight process-orientated categories affected by fishing, with case studies for each of them: target organisms, non-target organisms, nursery functions, trophic effects, habitat change, reduced water quality, human environment, and potential for local extinctions. Fishing in the estuarine and nearshore environment has clear impacts on the structure and functioning of these ecosystems, although other, non-fishing issues also effect these ecosystems. This creates multiple interactions and reinforces the need for an integrated approach to coastal zone management. Nonetheless, some form of fish-based action plan could be created, especially within estuaries, which would provide management objectives for a particular system.
TL;DR: Hydride is the ligand with the smallest number of valence electrons and thus an ideal choice for a precise calculation and has been a ligand of choice for EHT molecular orbital analysis and symmetry arguments and valence bond analysis.
Abstract: Hydride is the ligand with the smallest number of valence electrons and thus an ideal choice for a precise calculation. An H-containing transition metal system (MnH) was among the first species for testing the performance of ab initio computational methods on transition metal systems.1 Since hydride can only make a single bond to a transition metal center and has minimal steric influence, it is also the ideal ligand for establishing a basic bonding pattern associated with a given metal and coordination sphere. It has thus been a ligand of choice for EHT molecular orbital analysis. It is also an ideal ligand for establishing symmetry arguments and valence bond analysis. Hydride is the least computationally costly model for any σ donor group and has been used in ab initio calculations in particular to represent alkyl groups. Finally, it is a crucial computational benchmark † This work is dedicated to the memory of Jeremy K. Burdett (1947-1997), a great colleague and a dear friend, who actively participated in the early stages of this venture by establishing some of the basic rules for analyzing the structure and bonding in polyhydrides. * To whom correspondence should be addressed. E-mail: agusti@ klingon.uab.es (A.L.), odile.eisenstein@lsd.univ-montp2.fr. 601 Chem. Rev. 2000, 100, 601−636
TL;DR: The elaboration of solids from the molecular scale by a kinetically controlled methodology is one of the main challenges of molecular chemistry and offers wide perspectives because of the large possibilities opened by the organic unit.
Abstract: The elaboration of solids from the molecular scale by a kinetically controlled methodology is one of the main challenges of molecular chemistry. In the long term, this should permit the design of solids with desired properties. Here, some examples are given which show a few methods that have been used for the preparation of solids from molecular precursors. The one-pot synthesis of rheologically controlled SiC is described. Access to a new kind of ceramic is obtained by the same methodology using molecular precursors. Mixed ceramics with interpenetrating networks are not accessible by the chemical thermodynamic route. The chemistry of hybrid materials obtained from molecular precursors through inorganic polymerization is presented. This class of materials offers wide perspectives because of 1) the large possibilities opened by the organic unit, 2) the kinetic control, which permits any kind of texture for the solid, and 3) the aptitude of these solids to become nanostructured.
TL;DR: This study analyzes stroke phases and arm and leg coordination during front crawl swimming as a function of swim velocity and performance level and shows that duration of the propulsive phases (B + C) increased significantly with increasing velocity.
Abstract: This study analyzes stroke phases and arm and leg coordination during front crawl swimming as a function of swim velocity and performance level. Forty-three swimmers constituted three groups based on performance level. All swam at three different swim velocities, corresponding to the paces appropriate for the 800 m, 100 m, and 50 m. The different stroke phases and the arm and leg coordination were identified by video analysis. Arm coordination was quantified using a new index of coordination (IdC), which expresses the three major modalities opposition, catch-up and superposition. Opposition, where one arm begins the pull phase when the other is finishing the push phase; catch up, which has a lag time (LT) between propulsive phases of the two arms; and superposition, which describes an overlap in the propulsive phases. The IdC is an index which characterizes coordination patterns by measure of LT between propulsive phases of each arm. The most important results showed that duration of the propulsive phases (B + C) increased significantly with increasing velocity: 43.1 +/- 3.3% for V800; 46.5 +/- 3% for V100 and 49 +/- 3% for V50. The arm and leg synchronization was modified in the sense of an increase in six-beat kick. The IdC increased significantly with velocity: IdCV800 = -7.6 +/- 6.4%; IdCV100 = -3.2 +/- 5.1% and IdCV50 = -0.9 +/- 5.6%. IdC increased also significantly with performance level: IdCG3 = -6.07 +/- 5.3%; IdCG2 = -3.9 +/- 4.2% and IdCG1 = -1.76 +/- 5.6% for the mean of the 3 velocity. The two extreme IdC were IdCG3V800 = -9.4 +/- 5.4% and IdCG1V50 = +2.53 +/- 4.4%.
TL;DR: The successive emergence and amplification of distinct Ta L1 subfamilies shows that L1 evolution has been as active in recent human history as it has been found to be for rodent L1 families.
Abstract: L1 (LINE-1) elements constitute a large family of mammalian retrotransposons that have been replicating and evolving in mammals for more than 100 Myr and now compose 20% or more of the DNA of some mammals. Here, we investigated the evolutionary dynamics of the active human Ta L1 family and found that it arose approximately 4 MYA and subsequently differentiated into two major subfamilies, Ta-0 and Ta-1, each of which contain additional subsets. Ta-1, which has not heretofore been described, is younger than Ta-0 and now accounts for at least 50% of the Ta family. Although Ta-0 contains some active elements, the Ta-1 subfamily has replaced it as the replicatively dominant subfamily in humans; 69% of the loci that contain Ta-1 inserts are polymorphic for the presence or absence of the insert in human populations, as compared with 29% of the loci that contain Ta-0 inserts. This value is 90% for loci that contain Ta-1d inserts, which are the youngest subset of Ta-1 and now account for about two thirds of the Ta-1 subfamily. The successive emergence and amplification of distinct Ta L1 subfamilies shows that L1 evolution has been as active in recent human history as it has been found to be for rodent L1 families. In addition, Ta-1 elements have been accumulating in humans at about the same rate per generation as recently evolved active rodent L1 subfamilies.
TL;DR: In this paper, the authors studied the nonlinear dissipative dynamical system with Lipschitz continuous gradient and showed that, without peculiar assumptions, a trajectory may not converge to a critical point.
Abstract: Let H be a real Hilbert space and Φ:H ↦ R a continuously differentiable function, whose gradient is Lipschitz continuous on bounded sets. We study the nonlinear dissipative dynamical system: ${\ddot x}(t)+\lambda{\dot x}(t)+
abla\Phi(x(t))=0, \lambda>0, plus Cauchy data, mainly in view of the unconstrained minimization of the function Φ. New results concerning the convergence of a solution to a critical point are given in various situations, including when Φ is convex (possibly with multiple minima) or is a Morse function (the critical point being then generically a local minimum); a counterexample shows that, without peculiar assumptions, a trajectory may not converge. By following the trajectories, we obtain a method for exploring local minima of Φ. A singular perturbation analysis links our results with those concerning gradient systems.
TL;DR: In this article, the authors define three geochemical and structural domains of the Oman ophiolite: the main harzburgitic mantle section, the diapir areas, and the dunite transition zone.
TL;DR: The participation of 4f electrons in the bonding of the lanthanide complexes Ln(NR2)3; R = H, SiH3, has been investigated at the DFT level as mentioned in this paper.
Abstract: The participation of 4f electrons in the bonding of the lanthanide complexes Ln(NR2)3; R = H, SiH3, has been investigated at the DFT level. Structural parameters obtained with small core (f electrons in the valence) and large core (f electrons in the core) effective core potentials (ECPs) suggest the nonparticipation of the f electrons to the Ln−N bonding. A methodological study has been carried out on the lanthanide contraction with various ab initio methods using large core ECPs. The calculated lanthanide contraction (0.180 A) is in excellent agreement with the experimental value (0.179 A). Comparison of calculated structural parameters with available X-ray data shows that calculations with large core ECPs and density functional methods quantitatively reproduce the bonding at the lanthanide.
TL;DR: In this paper, the authors study coannihilation of the lightest neutralino with the lighter scalar top quark, and show that for natural values of the neutralino mass, the mass difference has to exceed 10$ to 30 GeV to contribute significantly to the dark matter.
Abstract: A stable neutralino ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0},$ assumed to be the lightest supersymmetric particle, is a favored particle physics candidate for cosmological dark matter. We study coannihilation of the lightest neutralino with the lighter scalar top quark ${t}_{1}.$ We show that for natural values of the neutralino mass, $\ensuremath{\lesssim}300$ GeV, the ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0}$-${t}_{1}$ mass difference has to exceed $\ensuremath{\sim}10$ to 30 GeV if ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0}$ is to contribute significantly to the dark matter. Scenarios with smaller mass splitting, where ${t}_{1}$ is quite difficult to detect at collider experiments, are thus cosmologically disfavored. On the other hand, for small ${t}_{1}$-${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0}$ mass splitting, we show that coannihilation allows superparticle masses well beyond the reach of the CERN LHC, ${m}_{{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0}}\ensuremath{\sim}5$ TeV, without ``overclosing'' the Universe.
TL;DR: It was shown by immunocytochemistry, at both optical and ultrastructural levels, that the peptides are localized in granulocyte cytoplasmic granules, which indicates that penaeidins are constitutively synthesized and stored in the shrimp haemocytes.
Abstract: Penaeidins are members of a new family of antimicrobial peptides isolated from a crustacean, which present both Gram-positive antibacterial and antifungal activities. We have studied the localization of synthesis and storage of penaeidins in the shrimp Penaeus vannamei. The distribution of penaeidin transcripts and peptides in various tissues reveals that penaeidins are constitutively synthesized and stored in the shrimp haemocytes. It was shown by immunocytochemistry, at both optical and ultrastructural levels, that the peptides are localized in granulocyte cytoplasmic granules. The expression and localization of penaeidins were further analysed in shrimp subjected to microbial challenge. We found that (1) penaeidin mRNA levels decrease in circulating haemocytes in the first 3 hours following stimulation and (2) an increase in plasma penaeidin concentration occurs after microbial challenge, together with (3) a penaeidin immunoreactivity in cuticular tissue, which can be related to the chitinbinding activity we demonstrate here for penaeidins. SUMMARY
TL;DR: In this article, a review of the current knowledge on the Oman-United Arab Emirates ophiolite belt and a new synthesis at the scale of the entire belt is presented.
Abstract: This study is altogether an extended legend for the folded maps incorporated in this volume, a review of the current knowledge on the Oman-United Arab Emirates ophiolite belt, and a new synthesis at the scale of the entire belt. Following a brief description of the petrological and structural units composing the ophiolite, the content of the three structural maps (planar structures, linear structures and dikes) is presented. Next, we discuss the various constraints introduced by these data in view of a synthesis of the ophiolite belt in terms of an ocean floor spreading system. Because they are the link between the factual results summarised in the maps, and the ridge models, these constraints are critical (and are central to the structural analysis of ophiolites). They introduce severe limits to possible ridge models such as those proposed in the conclusion. After being reassembled in a best geometrical and structural fit, the belt is parted into three domains (Figure 1). The south-eastern and central domains (from Wadi Tayin to Haylayn and possibly Sarami massifs) incorporate a 40–50 km-wide and possibly over 200 km long new ridge segment, oriented NW–SE, which is opening into a 1–2 My older lithosphere oriented NE–SW. The northern domain (from Khawr Fakkan to Hilti massifs) is well explained by a model of propagating (Aswad) and failing (Fizh) ridge segments of nearly parallel NNW-SSE orientation which are separated by a 10–20 km-wide transform zone covering the north of Fizh massif. This new synthesis integrates and updates the local syntheses published so far. It illustrates again the contrast between locally simple ridge segments organised around mantle diapirs and the tectonic complexity of the two larger domains, with, as an example, sheared mantle, vertical Moho and dismembered lower crust with hydrous contamination, near the tip of ridge propagators. The relation between the northern and central-southern domains is obscure because the paleomagnetic results suggest that, with respect to the central-southern domain, the northern domain should have rotated 130° clockwise. Such a large rotation of a 200 km long domain is difficult to explain, inasmuch as the age constraints seem to restrict the possible duration of the rotation to a couple of Myr. The preferred model consists in a progressive clockwise rotation during tectonic accretion of increasingly larger blocks. This is initiated in the northern massifs, progressing over 1–2 Myr, southward to finally integrate the entire ophiolite.
TL;DR: The Tinto river is strongly acidic (pH, 1.5-2.5); during flood events, it transports a sandy material, including abundant detrital pyrite grains as mentioned in this paper.
Abstract: The Tinto river drains the Rio Tinto mining district, which comprises the world’s largest known massive sulfide deposits; these orebodies have been mined from the third millenium BC to the present. The Tinto river is strongly acidic (pH, 1.5–2.5); during flood events, it transports a sandy material, including abundant detrital pyrite grains. A core drilled in the Holocene sediments of the Tinto estuary allows for investigation of recent and historical mining pollution. Two anomalous horizons have been recognized (0–1.3 m; 3–4 m). Both are characterized by very high metal content (100 times over the background) and by the presence of abundant clastic pyrite grains. The metal association (Pb, Ba, As, Cu, Zn, Sn, Tl, Cd, Ag, Hg, Au) is typical of that of the Rio Tinto pyritic ore. The upper horizon corresponds to the modern mining activity; the lower horizon has been dated at 2530 BC (14C AMS calibrated age).
We show here that active mining occurred early (Copper Age) in the Rio Tinto area, resulting in a watershed-scale metal contamination. We also show that anthropogenic input of metals may be accumulated and immobilized during thousands of years in estuarine sediments.
TL;DR: In Mytilus galloprovincialis, gene structure reveals synthesis as precursors in circulating hemocytes, and involvement in anti‐infectious responses is unique, and apparently more related to those of mammalian phagocytes than to Those of insects.
TL;DR: In this article, a series of 40Ar/39Ar age determinations on metamorphic micas along this transect on mineral populations and/or single grains were conducted. And the results showed: (1) the Late Oligocene-Early Miocene age of the top-to-east sense of shear in Alpine Corsica; (2) a transition from compression to extension around 32-Ma; (3) the eastward migration of the HP/LT event related to compression from 45 to 17-Ma, and of the LP event, related to extension
TL;DR: The results confirm that the xanthophyll cycle protects chloroplasts from photooxidation by a mechanism distinct from non-photochemical energy quenching and they reveal that the absence of xanthoptera cycle can be compensated by other protective mechanisms.
Abstract: The npq1 Arabidopsis mutant is deficient in the violaxanthin de-epoxidase enzyme that converts violaxanthin to zeaxanthin in excess light (xanthophyll cycle). We have compared the behavior of mature leaves (ML) and developing leaves of the mutant and the wild type in various light environments. Thermoluminescence measurements indicated that high photon flux densities (>500 micromol m(-2) s(-1)) promoted oxidative stress in the chloroplasts of npq1 ML, which was associated with a loss of chlorophyll and an inhibition of the photochemical activity. Illuminating leaf discs in the presence of eosin, a generator of singlet oxygen, brought about pronounced lipid peroxidation in npq1 ML but not in wild-type leaves. No such effects were seen in young leaves (YL) of npq1, which were quite tolerant to strong light and eosin-induced singlet oxygen. Non-photochemical energy quenching was strongly inhibited in npq1 YL and ML and was not improved with high-light acclimation. Our results confirm that the xanthophyll cycle protects chloroplasts from photooxidation by a mechanism distinct from non-photochemical energy quenching and they reveal that the absence of xanthophyll cycle can be compensated by other protective mechanisms. npq1 YL were observed to accumulate considerable amounts of vitamin E during photoacclimation, suggesting that this lipophilic antioxidant could be involved in the high phototolerance of those leaves.
TL;DR: Functional expression in HEK 293 cells of a full-length cDNA encoding the shortest α1G isoform identified to date resulted in transient, low threshold activated Ca2+ currents with the expected permeability ratio (I Sr >I Ca ≥ I Ba) and channel conductance (∼7 pS).
TL;DR: A large body of literature containing potentially important but poorly appreciated findings are reviewed, which together with recent results, argue for Leishmania-host-cell interactions that are much more complex than generally thought.