Showing papers by "University of Montpellier published in 1998"
TL;DR: A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier.
Abstract: The Quaternary cold periods in Europe are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in both animals and plants. The phylogeographies of 10 taxa, including mammals (Ursus arctos, Sorex spp., Crocidura suaveolens, Arvicola spp.), amphibians (Triturus spp.), arthropods (Chorthippus parallelus), and plants (Abies alba, Picea abies, Fagus sylvatica, Quercus spp.), were analysed to elucidate general trends across Europe. Only a small degree of congruence was found amongst the phylogeographies of the 10 taxa, but the likely postglacial colonization routes exhibit some similarities. A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier. The comparison of colonization routes highlighted four main suture-zones where lineages from the different refugia meet. Some of the intraspecific genetic distances among lineages indicated a prequaternary divergence that cannot be connected to any particular cold period, but are probably related mainly to the date of arrival of each taxon in the European continent. As a consequence, molecular genetics so far appears to be of limited use in dating Quaternary events.
2,855 citations
TL;DR: In this paper, the decay widths and branching ratios of the Higgs boson and the neutral and charged Higgs particles of the Minimal Supersymmetric extension of the Standard Model are calculated.
1,322 citations
TL;DR: In this article, a comparative study of the energetic, structural, and elastic properties of carbon and composite single-wall nanotubes is presented, using a nonorthogonal tight-binding formalism.
Abstract: We present a comparative study of the energetic, structural, and elastic properties of carbon and composite single-wall nanotubes, including BN, ${\mathrm{BC}}_{3}$, and ${\mathrm{BC}}_{2}\mathrm{N}$ nanotubes, using a nonorthogonal tight-binding formalism. Our calculations predict that carbon nanotubes have a higher Young modulus than any of the studied composite nanotubes, and of the same order as that found for defect-free graphene sheets. We obtain good agreement with the available experimental results.
1,210 citations
TL;DR: This work demonstrates that a modification of the voltage‐gated sodium channel protein recently shown to be associated with mutations of the para‐type sodium channel gene is present in certain strains of pyrethroid resistant A. gambiae, and describes a PCR‐based diagnostic test allowing its detection in the genome of single mosquitoes.
Abstract: Pyrethroid-impregnated bednets are playing an increasing role for combating malaria, especially in stable malaria areas. More than 90% of the current annual malaria incidence (c. 500 million clinical cases with up to 2 million deaths) is in Africa where the major vector is Anopheles gambiae s.s. As pyrethroid resistance has been reported in this mosquito, reliable and simple techniques are urgently needed to characterize and monitor this resistance in the field. In insects, an important mechanism of pyrethroid resistance is due to a modification of the voltage-gated sodium channel protein recently shown to be associated with mutations of the para-type sodium channel gene. We demonstrate here that one of these mutations is present in certain strains of pyrethroid resistant A. gambiae s.s. and describe a PCR-based diagnostic test allowing its detection in the genome of single mosquitoes. Using this test, we found this mutation in six out of seven field samples from West Africa, its frequency being closely correlated with survival to pyrethroid exposure. This diagnostic test should bring major improvement for field monitoring of pyrethroid resistance, within the framework of malaria control programmes.
940 citations
03 Jul 1998
TL;DR: A meta-model of artificial organization by which one can build multi-agent systems with different forms of organizations such as market-like and hierarchical organizations is presented, which allows for agent heterogeneity in languages, applications and architectures.
Abstract: This paper presents a generic meta-model of multi-agent systems based on organizational concepts such as groups, roles and structures. This model, called AALAADIN, defines a very simple description of coordination and negotiation schemes through multi-agent systems. Aalaadin is a meta-model of artificial organization by which one can build multi-agent systems with different forms of organizations such as market-like and hierarchical organizations. We show that this meta-model allows for agent heterogeneity in languages, applications and architectures. We also introduce the concept of organizational reflection which uses the same conceptual model to describe system level tasks such as remote communication and migration of agents. Finally, we briefly describe a platform, called MADKIT, based on this model. It relies on a minimal agent kernel with platform-level services implemented as agents, groups and roles.
852 citations
TL;DR: In this paper, the deformation of a curved interface between solid phases was studied under the assumption of small strains in the bulk phases and neglecting accretion at the interfaces, and the authors showed that the free energy of the interface can depend on the normal and tangential components of the jump in displacement at the interface (stretch and slip), and the average of the projected strain in the tangent plane (average tangential strain).
Abstract: We discuss the deformation of a curved interface between solid phases, assuming small strains in the bulk phases and neglecting accretion at the interfaces. Such assumptions are relevant to the deformation of solid microstructures when atomic diffusion and the formation of defects such as dislocations are negligible. We base our theory on a constitutive equation giving the (excess) free energy ψ of the interface when the interfacial limits of the displacement fields in the abutting phases as well as the limits of the displacement gradients are known. Using general considerations of frame invariance, we show that ψ can depend on these quantities at most through: firstly the normal and tangential components of the jump in displacement at the interface (stretch and slip), secondly the average of the projected strain in the tangent plane (average tangential strain), thirdly the tangential component of the jump in the projected displacement gradient at the interface (relative tangential strain and rel...
824 citations
TL;DR: In this article, the correlation between contact forces and the texture of a packing of rigid particles subject to biaxial compression is analyzed by means of numerical simulations, which provide evidence that the contact network can be decomposed unambiguously into two subnetworks with complementary mechanical properties.
Abstract: The correlation between contact forces and the texture of a packing of rigid particles subject to biaxial compression is analyzed by means of numerical simulations. Four different aspects are investigated: stress tensor, dissipation due to friction, angular distribution of forces, and fabric tensor characterizing the anisotropy of the texture. All of them provide evidence that the contact network can be decomposed unambiguously into two subnetworks with complementary mechanical properties.
701 citations
TL;DR: In this paper, a unique database of 110 olivine petrofabrics and their calculated seismic properties is presented, where a phenomenological relationship is established between P- and S-wave seismic anisotropy and the degree of crystal alignment.
595 citations
TL;DR: In this paper, the authors show that the origin of the electric field is predominently due to spontaneous polarization effects rather than a piezoelectric effect in the well material and conclude that the GaN layers are nearly unstrained, whereas the (AI,Ga)N barriers are pseudomorphically strained on GaN.
Abstract: (Al,Ga)N/GaN quantum wells have been studied by temperature-dependent luminescence and reflectivity. The samples were grown by molecular beam epitaxy on (0001) sapphire substrates, and well widths were varied from 3 to 15 monolayers (ML's) with a 2-ML increment, thus providing a reliable data set for the study of the well width dependence of transition energies. The latter shows a strong quantum confined Stark effect for wide wells, and an internal electric-field strength of 450 kV/cm is deduced. X-ray diffraction performed on the same samples shows that the GaN layers are nearly unstrained, whereas the (AI,Ga)N barriers are pseudomorphically strained on GaN. We conclude that the origin of the electric field is predominently due to spontaneous polarization effects rather than a piezoelectric effect in the well material. [S0163-1829(98)50944-7].
396 citations
TL;DR: Observations of students using graphic and symbolic calculators were analysed and categorised into profiles, illustrating that transforming the calculator into an efficient mathematical instrument varies from student to student, a factor which has to be included in the teaching process.
Abstract: Transforming any tool into a mathematical instrument for students involves a complex ‘instrumentation’ process and does not necessarily lead to better mathematical understanding. Analysis of the constraints and potential of the artefact are necessary in order to point out the mathematical knowledge involved in using a calculator. Results of this analysis have an influence on the design of problem situations. Observations of students using graphic and symbolic calculators were analysed and categorised into profiles, illustrating that transforming the calculator into an efficient mathematical instrument varies from student to student, a factor which has to be included in the teaching process.
386 citations
TL;DR: The high degree of protection observed with kynurenate attests that dendritic damage is an important component in noise-induced hearing loss and demonstrates that a synaptic repair mechanism occurring within the first few days post-exposure is partly responsible for the recovery of temporary threshold shifts after an acoustic trauma.
Abstract: Guinea-pigs were exposed to a traumatic sound inducing up to 80 dB hearing loss. Beside the well described mechanical damage to outer hair cells, a total disruption of inner hair cell (IHC)-auditory nerve synapses was acutely observed within the traumatized area. To test the hypothesis that synaptic damage is due to an excessive release of glutamate by the IHCs, we examined the protective effect of the glutamate antagonist kynurenate on noise-induced hearing loss. The high degree of protection observed with kynurenate attests that dendritic damage is an important component in noise-induced hearing loss. Moreover, we demonstrate that a synaptic repair mechanism occurring within the first few days post-exposure is partly responsible for the recovery of temporary threshold shifts after an acoustic trauma.
TL;DR: This issue might soon be resolved provided clear hypotheses and definitions are used and the problem of the neutrality of allozyme variation is not identified with the related issue of HFC, as well as new empirical & theoretical tools.
Abstract: Heterozygosity–fitness correlations (HFC) have been studied in various organisms for more than two decades, but they are not universal. Although their detectability is limited by several factors (null alleles, inaccuracy of the phenotypic description of fitness, small sample sizes) the correlations appear intrinsically weak and often inconsistent across samples. Determining the origins of HFC is therefore a complex task. However, this issue might soon be resolved provided clear hypotheses and definitions are used (especially, if the problem of the neutrality of allozyme variation is not identified with the related issue of HFC), as well as new empirical (molecular markers) & theoretical (statistical models) tools.
TL;DR: Mimicry is today a broad field of evolutionary study; here the evolution of its diversity in predator-prey systems is discussed.
Abstract: Visual mimicry is a textbook case of natural selection because it is both intuitively understandable and has repeatedly evolved in a range of organisms: it is the ultimate example of parallel evolution. In many mimetic groups, particularly butterflies, a huge variety of colour patterns has arisen, even in closely related species. There has been much recent controversy over explanations of this variety. Mimicry is today a broad field of evolutionary study; here we discuss the evolution of its diversity in predator–prey systems.
TL;DR: In this paper, the use of Thlaspi caerulescens was studied by pot trials in plant growth units and in populations of wild plants growing over Pb/Zn base-metal mine wastes at Les Malines in the south of France.
Abstract: Uptake of Cd, Zn, Pb and Mn by the hyperaccumulator Thlaspi caerulescens was studied by pot trials in plant growth units and in populations of wild plants growing over Pb/Zn base-metal mine wastes at Les Malines in the south of France. The pot trials utilised metal-contaminated soils from Auby in the Lille area. Zinc and Cd concentrations in wild plants averaged 1.16% and 0.16% (dry weight) respectively. The unfertilised biomass of the plants was 2.6 t/ha. A single fertilised crop with the above metal content could remove 60 kg of Zn and 8.4 kg Cd per hectare. Experiments with pot-grown and wild plants showed that metal concentrations (dry weight basis) were up to 1% Zn (4% Zn in the soil) and just over 0.1% Cd (0.02% Cd in the soil). The metal content of the plants was correlated strongly with the plant-available fraction in the soils as measured by extraction with ammonium acetate and was inversely correlated with pH. Bioaccumulation coefficients (plant/soil metal concentration quotients) were in general higher for Cd than for Zn except at low metal concentrations in the soil. There was a tendency for these coefficients to increase with decreasing metal concentrations in the soil. It is proposed that phytoremediation using Thlaspi caerulescens would be entirely feasible for low levels of Cd where only a single crop would be needed to halve a Cd content of 10 μg/g in the soil. It will never be possible to remediate elevated Zn concentrations within an economic time frame (<10 yr) because of the lower bioaccumulation coefficient for this element coupled with the much higher Zn content of the soils.
TL;DR: In this paper, the authors show that carbon nanostructures such as singlewalled and multi-walled nanotubes (SWNTs and MWNTs) or graphitic polyhedral nanoparticles can be produced using various methods, such as electric arc discharge process, the laser ablation method, or the solar tech- nique.
Abstract: Carbon nanostructures such as single-walled and multi-walled nanotubes (SWNTs and MWNTs) or graphitic polyhedral nanoparticles can be produced using various methods. Most of them are based on the sublimation of carbon under an inert atmosphere, such as the electric arc discharge process, the laser ablation method, or the solar tech- nique. But chemical methods can also be used to synthesize these kinds of carbon materials: the catalytic decomposi- tion of hydrocarbons, the production by electrolysis, the heat treatment of a polymer, the low temperature solid pyrolysis, or the in situ catalysis.
TL;DR: The Barombi Mbo pollen record goes back to about 28,000 yr B.P. as discussed by the authors and is divided into four main pollen zones: Zone I, Zone II, Zone III, Zone IV and Zone V.
TL;DR: Underlining the role of shear stresses in the granulometric distribution of a biological suspension and in the mechanisms of membrane fouling reveals that these different soluble products and their interaction with the membrane material play a major role in the fouling mechanism.
TL;DR: 4-hydroxyisoleucine insulinotropic activity might, at least in part, account for fenugreek seeds' antidiabetic properties and may be considered as a novel drug with potential interest for the treatment of NIDDM.
Abstract: We report the characterization of a new insulinotropic compound, 4-hydroxyisoleucine. This amino acid has been extracted and purified from fenugreek seeds, which are known in traditional medicine for their antidiabetic properties. 4-Hydroxyisoleucine increases glucose-induced insulin release, in the concentration range of 100 μmol/l to 1 mmol/l, through a direct effect on isolated islets of Langerhans from both rats and humans. The stimulating effect of 4-hydroxyisoleucine was strictly glucose dependent; indeed, ineffective at low (3 mmol/l) or basal (5 mmol/l) glucose concentrations, the amino acid potentiated the insulin secretion induced by supranormal (6.6–16.7 mmol/l) concentrations of glucose. In addition, in the isolated perfused rat pancreas, we could show 1 ) that the pattern of insulin secretion induced by 4-hydroxyisoleucine was biphasic, 2 ) that this effect occurred in the absence of any change in pancreatic α-and δ-cell activity, and 3 ) that the more glucose concentration was increased, the more insulin response was amplified. Moreover, 4-hydroxyisoleucine did not interact with other agonists of insulin secretion (leucine, arginine, tolbutamide, glyceraldehyde). Therefore, we conclude that 4-hydroxyisoleucine insulinotropic activity might, at least in part, account for fenugreek seeds' antidiabetic properties. This secretagogue may be considered as a novel drug with potential interest for the treatment of NIDDM.
TL;DR: The family of tin monochalcogenides was calculated in this paper in order to point out trends in properties, and electronic structures were calculated from density functional theory pseudopotential and tight-binding theories.
Abstract: The family of tin monochalcogenides $(\mathrm{Sn}X,$ $X=\mathrm{O},$ S, Se, or Te) is calculated in order to point out trends in properties. Electronic structures are calculated from density functional theory pseudopotential and tight-binding theories. Resulting densities of states present similar features. Calculated $\mathrm{Sn}(5s)$ populations and charge-density contours are shown to be consistent with the presence of a lone pair. The lone pair is also studied from M\"ossbauer spectroscopy, which points out the particular case of SnO.
TL;DR: It is argued that rDNA homogeneity over the species range of T. urticae results from the high colonization potential of this species, preventing long-term differentiation.
Abstract: We compared patterns of intraspecific polymorphism of two markers with contrasted modes of evolution, nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA), in the phytophagous mite Tetranychus urticae Koch. The second internal transcribed spacer (ITS2) of rDNA and a fragment in the mtDNA gene coding for Cytochrome Oxidase I (COI), were PCR-amplified and sequenced in samples of various geographical origins distributed worldwide. The 15 COI haplotypes found fell into two major phylogenetic lineages differing by an average of 5% nucleotide divergence. Samples from the Mediterranean basin were represented in both lineages, and showed no phylogeographical structure. The other samples, from temperate regions of the northern hemisphere, were clustered in one of the lineages and displayed little variation, indicating a recent colonization of this region. In contrast, no variation at all was found at the ITS2 in this species. We sequenced both COI and ITS2 in four other species of the genus Tetranychus and found that, despite the absence of intraspecific polymorphism, ITS appears to evolve 2.5 times faster than COI. We argue that rDNA homogeneity over the species range of T. urticae results from the high colonization potential of this species, preventing long-term differentiation. Preliminary data on two other mite species (Amphitetranychus viennensis Zacher and Mononychellus progresivus Doreste) with stricter ecological requirements and more restricted colonization potential revealed substantial and concordant geographical differentiation for both ITS2 and COI.
TL;DR: In this article, two types of subducting seamounts were modelled: relatively small conical seamount and larger flat-topped seamount, and the surface deformation directly comparable with seafloor morphology.
TL;DR: Analysis of the function of the Rho proteins Rac1 and CDC42 in the high affinity receptor for IgE‐mediated phagocytosis using transfected rat basophil leukemia mast cells shows that Rac1 or CDC42 are required to coordinate actin filament organization and membrane extension to formphagocytic cups and to allow particle internalization during FcR‐mediatedPhagocyTosis.
Abstract: At the surface of phagocytes, antibody-opsonized particles are recognized by surface receptors for the Fc portion of immunoglobulins (FcRs) that mediate their capture by an actin-driven process called phagocytosis which is poorly defined. We have analyzed the function of the Rho proteins Rac1 and CDC42 in the high affinity receptor for IgE (FcepsilonRI)-mediated phagocytosis using transfected rat basophil leukemia (RBL-2H3) mast cells expressing dominant inhibitory forms of CDC42 and Rac1. Binding of opsonized particles to untransfected RBL-2H3 cells led to the accumulation of F-actin at the site of contact with the particles and further, to particle internalization. This process was inhibited by Clostridium difficile toxin B, a general inhibitor of Rho GTP-binding proteins. Dominant inhibition of Rac1 or CDC42 function severely inhibited particle internalization but not F-actin accumulation. Inhibition of CDC42 function resulted in the appearance of pedestal-like structures with particles at their tips, while particles bound at the surface of the Rac1 mutant cell line were enclosed within thin membrane protrusions that did not fuse. These phenotypic differences indicate that Rac1 and CDC42 have distinct functions and may act cooperatively in the assembly of the phagocytic cup. Inhibition of phagocytosis in the mutant cell lines was accompanied by the persistence of tyrosine-phosphorylated proteins around bound particles. Phagocytic cup closure and particle internalization were also blocked when phosphotyrosine dephosphorylation was inhibited by treatment of RBL-2H3 cells with phenylarsine oxide, an inhibitor of protein phosphotyrosine phosphatases. Altogether, our data show that Rac1 and CDC42 are required to coordinate actin filament organization and membrane extension to form phagocytic cups and to allow particle internalization during FcR-mediated phagocytosis. Our data also suggest that Rac1 and CDC42 are involved in phosphotyrosine dephosphorylation required for particle internalization.
University of Turin1, University of Milan2, Darmstadt University of Applied Sciences3, Stanford University4, University of Hamburg5, University of Vienna6, CERN7, Lorentz Institute8, RWTH Aachen University9, Moscow State University10, Weizmann Institute of Science11, University of Glasgow12, University of Florence13, Northeastern University14, Istituto Nazionale di Fisica Nucleare15, Paul Scherrer Institute16, Centre national de la recherche scientifique17, University of Cambridge18, University of Montpellier19, Rutherford Appleton Laboratory20, University of Paris21, Leipzig University22, University of Geneva23, Indian Institute of Science24, Aristotle University of Thessaloniki25, Karlsruhe Institute of Technology26, Helsinki Institute of Physics27, Heidelberg University28, Silesian University29, University of Warsaw30, Max Planck Society31, Ludwig Maximilian University of Munich32, Autonomous University of Barcelona33, Sapienza University of Rome34, University College London35, University of Barcelona36, University of Bergen37, University of Trieste38, Rutgers University39, University of Valencia40, University of Würzburg41, Lund University42, Durham University43
TL;DR: The physics potential of linear linear colliders has been discussed in this paper, where the authors describe the potential for the discovery of particles in supersymmetric extensions of the Standard Model, the spectrum of Higgs particles, the super-ymmetric partners of the electroweak gauge and Higgs bosons.
TL;DR: In this paper, the authors used simulated annealing to fit four commonly used models to predict the dates of flowering of temperatezone trees, the spring warming, sequential, parallel and alternating models.
Abstract: The aim of the present study was to test the four commonly used models to predict the dates of flowering of temperatezone trees, the spring warming, sequential, parallel and alternating models. Previous studies concerning the performance of these models have shown that they were unable to make accurate predictions based on external data. One of the reasons for such inaccuracy may be wrong estimations of the parameters of each model due to the non-convergence of the optimization algorithm towards their maximum likelihood. We proposed to fit these four models using a simulated annealing method which is known to avoid local extrema of any kind of function, and thus is particularly well adapted to fit budburst models, as their likelihood function presents many local maxima. We tested this method using a phenological dataset deduced from aeropalynological data. Annual pollen spectra were used to estimate the dates of flowering of the populations around the sampling station. The results show that simulated annealing provides a better fit than traditional methods. Despite this improvement, classical models still failed to predict external data. We expect the simulated annealing method to allow reliable comparisons among models, leading to a selection of biologically relevant ones.
TL;DR: Analysis of the practical knowledge of expert sailing coaches of the French team preparing for the 1996 Olympic Games in Atlanta showed that coaching tasks were considered as a set of interacting constraints which generate complex, contradictory, and ill defined problems.
Abstract: The purpose of this study was to analyze the practical knowledge of expert sailing coaches of the French team preparing for the 1996 Olympic Games in Atlanta. Coaching knowledge was studied from a cognitive ergonomics perspective based on the task activity model. According to this model, a task is a set of constraints facing individuals. To meet the demands imposed by these constraints, an individual engages in an adaptative activity which can be studied from the point of view of his or her knowledge and cognitive operating modes. In-depth interviews were conducted after observation of five training sessions, and the verbal protocols obtained were coded inductively. The results showed that coaching tasks were considered by coaches as a set of interacting constraints which generate complex, contradictory, and ill defined problems. Coaches' operating modes appeared to be based on organization routines, cognitive anticipation on flexible plans, flexible on-site adaptation, joint control of training with athletes, and involvement in the training situation based on past experiences.
TL;DR: In this article, a continuous-wave 250 W CO2-laser operating at 106 μm has been employed to evaporate graphite/bi-metal targets in a vertical evaporation chamber.
TL;DR: In this paper, the masses and decay widths of the gluonia using QCD spectral sum rules and low energy theorems were derived for the scalar and tensor sectors.
TL;DR: The essential oils of Hoslundia opposita, Hyptis lanceolata, H. suaveolens, T. capense, P. guineense and Bixa orellana were analysed by GC and combined GC-MS as mentioned in this paper.
Abstract: The essential oils of Hoslundia opposita Vahl. (leaves), Hyptis lanceolata Poit. (whole plant), Hyptis suaveolens Poit. (leaves), Ocimum basilicum L. (whole plant), Ocimum canum Sim. (whole plant), Ocimum gratissimum L. (leaves), Plectranthus glandulosus Hook (leaves), Thymus vulgaris L. (whole plant), Piper capense L. (leaves and seeds), Piper guineense Schum. et Thom. (leaves and seeds) and Bixa orellana L. (leaves) which were obtained by hydrodistillation from plants collected in different regions of Cameroon, were analysed by GC and combined GC–MS. The oils of Hoslundia opposita, Hyptis lanceolata, H. suaveolens, T. vulgaris, P. capense, P. guineense and B. orellana were found to be rich in hydrocarbons (>58%). The most abundant compounds in the oils of O. basilicum, O. canum and P. glandulosus were alcohols and oxides (>40%), while in the oil of O. gratissimum the amounts of hydrocarbons and oxygen-containing components were roughly the same. It is of interest to note the presence in O. basilicum and P. guineense (leaves) of aromatic compounds in a sizeable amount (13.5% and 25.6% respectively). The antifungal activity of these essential oils against Candida albicans, Cryptococcus neoformans, Aspergillus flavus, Aureobasidium pullulans, Microsporum gypseum, Trichophyton rubrum, and Trichoderma viride were also investigated. Two methods were used for these antifungal tests: the microatmosphere method and the standardized broth dilution micromethod. Three oils (from Ocimum gratissimum, Thymus vulgaris and Ocimum basilicum) showed strong antifungal activity. © 1998 John Wiley & Sons, Ltd.
TL;DR: Evidence is presented that the high levels of two enzymes implicated in antioxidative defence, superoxide dismutase (SOD) and catalase, combined with changes in the three different classes of SOD during the storage stage are involved in delaying the senescence process in Clipper and this could explain, at least, to some extent, the long storage life of Clipper.
Abstract: We investigated the senescence process in two nonnetted muskmelon (Cucumis melo L.)␣varieties␣Clipper and Jerac differing in their storage life. Our results indicate that senescence in Jerac (the short-storage-life variety, less than 7 d) is the result of lipid peroxidation by free radicals, membrane phospholipid breakdown, and a drop in the level of antioxidants, resulting in increased membrane leakiness. By contrast, evidence is presented that the high levels of two enzymes implicated in antioxidative defence, superoxide dismutase (SOD) and catalase, combined with changes in the three different classes of SOD during the storage stage, are involved in delaying the senescence process in Clipper and this could explain, at least, to some extent, the long storage life of Clipper (longer than 14 d).
TL;DR: The influence of sleep on the incidence of seizures and the reciprocal effects of epilepsy on sleep were analyzed in 30 patients with intractable partial seizures, all candidates for surgery.
Abstract: Summary: Purpose: The influence of sleep on the incidence of seizures and the reciprocal effects of epilepsy on sleep were analyzed in 30 patients with intractable partial seizures, all candidates for surgery.
Methods: The patients were classified into two groups of 15 patients according to the documented site of the epileptogenic zone: frontal lobe epilepsy (FLE) and medial temporal lobe epilepsy (TLE). Frequency and waking-sleep distribution of seizures were evaluated by continuous video-EEG monitoring for 5 days, under defined antiepileptic drug (AED), sleep, and sleep deprivation regimens. Sleep organization was analyzed by polysomnography prior to the presurgical protocol.
Results: Significant differences were found between the two groups in sleeping-waking distribution of seizures under varied conditions, and in the quality of sleep organization. In FLE patients, seizures most often occurred during sleep, although sleep organization was normal. In TLE patients, most seizures occurred while patients were awake, and sleep organization was characterized by a low efficiency index. The difference in seizure distribution between FLE and TLE persisted under all conditions investigated, i.e., after AED discontinuation and sleep deprivation.
Conclusions: Sleep recording may be useful for diagnosis of FLE, and monitoring after sleep deprivation for that of TLE. We speculate that sleep-related seizures in FLE may depend on interaction between frontal lobe areas with the thalamus cortical synchronization system and the acetylcholine regulatory system of waking.