Showing papers by "Spanish National Research Council published in 1996"
TL;DR: This biennial Review summarizes much of particle physics, using data from previous editions.
12,798 citations
TL;DR: A better knowledge of the factors controlling the formation of amines is necessary in order to improve the quality and safety of food as discussed by the authors, which can be found in both raw and processed foods.
1,283 citations
TL;DR: Ex- trapolation of these results to the global ocean identifies marine angiosperms, which only contribute 4% of total ocean NPP, as major contributors of the NPP stored and subsequently buried in marine sediments, to lead to estimates of total burial of marine NPP that exceed current estimates by 15-50%.
Abstract: The fate of photosynthetic carbon in marine ecosystems dominated by different types of primary producers was examined by compiling published reports on herbivory, autotrophic respiration, decomposition, carbon storage, and export rates as fractions of net primary production (NPP) in ecosystems dominated by different types of autotrophs (i.e. oceanic and coastal phytoplankton, microphytobenthos, reef algae, macroalgae, seagrasses, marsh plants, and mangroves). A large fraction (>40%) of the NPP of marine ecosystems is decomposed within the system, except for microphytobenthos (decomposition, -25% of NPP). Herbivory tends to be highest for microalgae (planktonic and benthic, >40% of NPP) and macroalgae (33.6 ?4.9% of NPP) and is somewhat less for higher plants. Microphytobenthos export on average a much higher proportion of their NPP than do other microalgal communities, whereas marine macrophytes, except marsh plants, export a substantial proportion (24.3-43.5% on average) of their NPP. The fraction of NPP stored in sediments is 4-fold greater for higher plants (- 10-1 7% of NPP) than for algae (0.4-6% of NPP). On average, -90% of the phytoplankton NPP is used to support local heterotrophic metabolism (i.e. grazed or decomposed). This fraction is even higher in oceanic communities. Mangrove forests, and to a lesser extent seagrass meadows and macroalgal beds, produce organic carbon well in excess of the ecosystem requirements, with excess photosynthetic carbon (i.e. export rate plus storage) in these ecosystems representing -40% of NPP. Ex- trapolation of these results to the global ocean identifies marine angiosperms, which only contribute 4% of total ocean NPP, as major contributors of the NPP stored (30% of total ocean carbon storage) and subsequently buried in marine sediments. Consideration of burial of NPP from marine angiosperms should lead to estimates of total burial of marine NPP that exceed current estimates by 15-50%.
858 citations
TL;DR: A series of coals varying in rank from peat to semi-anthracite was studied by Fourier Transform infrared spectroscopy (FTIR) and curve-fitting analysis in order to gain additional information on coal structure and the main structural changes that take place during the coalification process.
699 citations
TL;DR: In this paper, a method for resistant starch (RS) determination in food and food products is proposed, the main features are: removal of protein; removal of digestible starch; solubilization and enzymatic hydrolysis of RS; and quantification of RS as glucose released.
693 citations
TL;DR: The treatment of patients with major depression using an SSRI and pindolol, a 5-HT1A/ beta-adrenoceptor antagonist, markedly reduced the latency of the antidepressant response in previously untreated patients and induced a rapid improvement in treatment-resistant patients.
661 citations
TL;DR: In this paper, a review summarizes different catalytic options for the production of syngas and hydrogen starting from simple hydrogen-containing molecules, focusing on new direct catalytic alternatives in natural gas conversion.
Abstract: This review summarizes different catalytic options for the production of syngas and hydrogen starting from simple hydrogen-containing molecules. Particular attention is given to new direct catalytic alternatives in natural gas conversion. Improvements in syngas technology are discussed, including partial oxidation, autothermal reforming, combined reforming and carbon dioxide reforming, and the energy efficiencies of direct and indirect methane conversion are compared. Processes, issues and practical difficulties are discussed with academic and applied efforts presented in parallel. It is emphasized that most of the ongoing research related to the direct processes is at the exploratory stage while technology utilizing indirect approach has advanced to semi-works and initial commercialization plants. The new emerging processes based on partial oxidation features are unique for syngas generation. Further enhancement of such processes plus improvements in other second generation technologies and advances in direct processes are anticipated to provide additional, new attractive paths to the chemical conversion of natural gas. Similarly, on board generation of hydrogen-rich gaseous fuels either for spark ignition engines or for coupled-fuel-cells electric engines is discussed within the scope of both partial oxidation and catalytic decomposition of methanol. A concept based in the thermochemical water splitting, which provides a renewable portable fuel from water in the form of H2, is also presented. Above all, as the chemistry involved in most of these catalytic alternatives takes place under extreme conditions, highly stable catalysts and engineering concepts are being developed.
660 citations
TL;DR: It is shown that a current-biased series array of nonidentical Josephson junctions undergoes two transitions as a function of the spread of natural frequencies, and the system can be mapped onto an exactly solvable model introduced by Kuramoto and the transition points can be accurately predicted.
Abstract: We show that a current-biased series array of nonidentical Josephson junctions undergoes two transitions as a function of the spread of natural frequencies. One transition corresponds to the onset of partial synchronization, and the other corresponds to complete phase locking. In the limit of weak coupling and disorder, the system can be mapped onto an exactly solvable model introduced by Kuramoto and the transition points can be accurately predicted.
503 citations
TL;DR: In situ hybridization analysis of chick embryos in whole-mount and tissue sections is presented, as they enable high sensitivity, a single cell resolution of signal, the ability to visualize gene expression in whole embryos, and detection of multiple RNAs can be carried out.
Abstract: Publisher Summary This chapter presents in situ hybridization analysis of chick embryos in whole-mount and tissue sections. Detection of the temporal and spatial regulation of gene expression in embryos is essential for elucidating the developmental functions of genes and for elucidating the cell interactions that regulate tissue patterning and differentiation. Patterns of gene expression can be visualized by detecting the encoded protein product by immunocytochemistry or messenger RNA using in situ hybridization. In situ hybridization to RNA involves a series of procedures—namely, (1) synthesis of a labeled nucleic acid probe complementary to the target mRNA, (2) fixation and permeabilization of tissue, (3) hybridization of probe to the tissue and washing to remove unhybridized probe, and (4) detection of the probe. Many types of probe and methods of labeling and visualization are used for in situ hybridization to embryos. Hapten-labeled single-stranded RNA probes are most commonly used, as they enable high sensitivity, a single cell resolution of signal, the ability to visualize gene expression in whole embryos, and detection of multiple RNAs can be carried out. Following hybridization and washing, the location of probe is detected with a hapten-binding protein conjugated to an enzyme. A number of haptens and enzyme conjugates of hapten-binding proteins are available: haptens include digoxigenin, fluorescein, and dinitrophenol that can be detected with commercially available antibodies, and enzymes include alkaline phosphatase and horse radish peroxidase.
502 citations
TL;DR: In this article, the general features of tapping mode operation of a scanning force microscope are presented, such as forces, deformation, and contact times, and they can be calculated as fun...
Abstract: The general features of tapping mode operation of a scanning force microscope are presented. Relevant factors of tapping mode such as forces, deformation, and contact times can be calculated as fun...
464 citations
TL;DR: The validity of the Red Queen hypothesis and of the competitive exclusion principle for RNA viruses are viewed as the expected result of the highly variable and adaptable nature of viral quasispecies.
Abstract: A hallmark of RNA genomes is the error-prone nature of their replication and retrotranscription. The major biochemical basis of the limited replication fidelity is the absence of proofreading/repair and postreplicative error correction mechanisms that normally operate during replication of cellular DNA. In spite of this unique feature of RNA replicons, the dynamics of viral populations seems to follow the same basic principles that classical population genetics has established for higher organisms. Here we review recent evidence of the profound effects that genetic bottlenecks have in enhancing the deleterious effects of Muller's ratchet during RNA virus evolution. The validity of the Red Queen hypothesis and of the competitive exclusion principle for RNA viruses are viewed as the expected result of the highly variable and adaptable nature of viral quasispecies. Viral fitness, or ability to replicate infectious progeny, can vary a million-fold within short time intervals. Paradoxically, functional and str...
TL;DR: An exhaustive review on the photochemical properties of iron-doped TiO2 semiconductors is presented in this article, where different aspects relating to structural, surface and photophysical properties of these photocatalysts are extensively discussed.
Abstract: An exhaustive review on the photochemical properties of iron-doped TiO2 semiconductors is presented. Photocatalytic reactions (reductions and oxidations) using Fe-containing TiO2 on different organic and inorganic substrates are reported. Different aspects relating to structural, surface and photophysical properties of these photocatalysts are extensively discussed. The origin of the photoactivity of this kind of mixed oxides is considered with regards to previously proposed physical and chemical processes and on the role of the iron content.
TL;DR: A review of the different electrochemnical methods used for measuring this parameter is made in this paper, where polarization curves, polarization resistance transient techniques and electrochemical impedance are commented on.
TL;DR: The results obtained show that superphosphate is the fertilizer that contains the highest concentrations of Cd, Co, Cu and Zn as impurities, and copper sulphate and iron sulphate have the most significant concentrations of Pb, and are the only fertilizers in which Ni was detected.
TL;DR: It is concluded that cells of the primary olfactory cortex derive from the lateral ganglionic eminence and that some early generated cells migrating from the longitudinal eminence transgress the cortico-striatal boundary entering the preplate of the neocortical primordium.
Abstract: From previous developmental studies, it has been proposed that the neurons of the ventrolateral cortex, including the primary olfactory cortex, differentiate from progenitor cells in the lateral ganglionic eminence. The objective of the present study was to test this hypothesis. The cells first generated in the forebrain of the rat migrate to the surface of the telencephalic vesicle by embryonic day (E) 12. Using [ 3 H]thymidine, we found that most of these cells contributed to the formation of the deep layer III of the primary olfactory cortex. To study the migratory routes of these cells, we made localized injections of the carbocyanine fluorescent tracers DiI and DiA into various parts of the lateral ganglionic eminence in living embryos at E12–E14 and subsequently maintained the embryos in a culture device for 17–48 hr. After fixation, most migrating cells were located at the surface of the telencephalic vesicle, whereas others were seen coursing tangentially into the preplate. Injections made at E13 and in fixed tissue at E15 showed that migrating cells follow radial glial fibers extending from the ventricular zone of the lateral ganglionic eminence to the ventrolateral surface of the telencephalic vesicle. The spatial distribution of radial glial fibers was studied in Golgi preparations, and these observations provided further evidence of the existence of long glial fibers extending from the ventricular zone of the lateral ganglionic eminence to the ventrolateral cortex. We conclude that cells of the primary olfactory cortex derive from the lateral ganglionic eminence and that some early generated cells migrating from the lateral ganglionic eminence transgress the cortico-striatal boundary entering the preplate of the neocortical primordium.
TL;DR: The data supported the hypothesis that differentiation, as seen among functional groups of species in terms of leaf habit and life-form, corresponded with differentiation in mean RGR and other seedling attributes, and deciduous species grew consistently faster than evergreens.
Abstract: 1 Innate mean relative growth rate (mean RGR) of seedlings is a key attribute for the performance of species in their natural habitats. This study aimed firstly at identifying easily measurable correlates of mean RGR of temperate zone woody species. Secondly, it tested the hypothesis that functional groups of woody plants could be characterized by their mean RGR and associated allocation and leaf attributes. 2 In a standardized experiment, 80 woody species from the British Isles and North Spain, ranging widely in leaf habit and life-form, were screened for seed weight and potential seedling mean relative growth rate (RGR), biomass allocation and leaf attributes. 3 Mean RGR, when based on plant weights excluding any attached thick cotyledons, was linearly and closely correlated with leaf area ratio (LAR, total leaf area/plant dry weight) and one of the two components of LAR, specific leaf area (SLA, leaf area/leaf dry weight). The other component, leaf weight fraction (leaf weight/plant dry weight), was only correlated with mean RGR when based upon true leaves, disregarding leafy cotyledons. These relationships were also demonstrated when taxonomic relatedness was accounted for. 4 The data supported the hypothesis that differentiation, as seen among functional groups of species in terms of leaf habit and life-form, corresponded with differentiation in mean RGR and other seedling attributes. For instance, deciduous species grew consistently faster than evergreens. 5 When SLA was split into its two components, specific saturated leaf area (SSLA, total leaf area/total saturated leaf weight) and leaf saturated weight/dry weight ratio (SW/DW), it was found that SSLA was consistently smaller in evergreens than in deciduous species, both for sclerophyllous and succulent leaves. Among species of the same leaf habit, variation in SLA among life-forms could be explained by variation in leaf SW/DW. 6 SSLA and leaf SW/DW, both easy to measure, together could help to categorize growth rate within the evergreen or deciduous species. This may be useful in vegetation monitoring. 7 The data may provide useful predictive tools to infer potential growth rates and nutrient conservation strategies of real vegetation from the functional attributes and composition of its functional species groups.
TL;DR: In this article, the main magnetic characteristics regarding the domain structure and magnetization processes (axial, circular and Matteucci and inverse Wiedemann effects) of amorphous wires and glass-coated microwires are analyzed.
Abstract: The main magnetic characteristics regarding the domain structure and magnetization processes (axial, circular and Matteucci and inverse Wiedemann effects) of amorphous wires and glass-coated microwires are analysed. Magnetic bistability, spontaneously observed in samples with large enough ratio magneto-elastic anisotropy with axial easy axis to shape anisotropy, is the main source for a number of sensor applications in pulse generators, position and field sensors, encoded security tags, rotational counters, magnetostrictive delay lines, and so on. The relevant perspectives of the novel giant magneto-impedance effect recently reported and observed in non-magnetostrictive samples are also introduced.
TL;DR: In this paper, a complete analysis of all potentially dangerous directions in the field space of the minimal supersymmetric standard model is carried out, and corresponding new constraints on the parameter space are given in an analytic form, representing a set of necessary and sufficient conditions to avoid dangerous directions.
TL;DR: The results obtained suggest that differences in catalytic properties probably exist between different Mn(2+)-oxidizing peroxidases produced by these fungi, and higher resistance to H2O2.
Abstract: The ligninolytic basidiomycetes Pleurotus eryngii, Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus sajor-caju did not exhibit detectable levels of manganese peroxidase (MP) when grown in liquid media with ammonium tartrate as N source. However, after examination of cells grown on different organic N-based media, high MP activity was obtained in peptone medium, up to nearly 3 U/ml in cultures of P. eryngii. Moreover, Mn2+ supplementation was not used to produce MP, since all Mn2+ concentrations assayed (1–4000 μM) inhibited production of this enzyme in liquid medium.
Two MP isoenzymes were purified to homogeneity from shaken or stationary cultures of P. eryngii grown in peptone medium. The purification process (which included chromatography on Biorad Q-cartridge, Sephacryl S-200 and Mono-Q) attained 56% activity yield with a purification factor of 25. The isoenzymes differed in pI (3.75 and 3.65), N-terminal sequence and some catalytic properties. They were in some aspects (e.g., molecular mass of 43 kDa) similar to Phanerochaete chrysosporium MP but exhibited some distinct characteristics, including Mn2+ -independent peroxidase activities against 2,6-dime-thoxyphenol and veratryl alcohol, and higher resistance to H2O2. Recent studies have shown that MP are ubiquitous enzymes in ligninolytic fungi, but the results obtained suggest that differences in catalytic properties probably exist between different Mn2+ -oxidizing peroxidases produced by these fungi.
TL;DR: This paper focuses on gelled food systems, reviewing and discussing the evolution of the initial terminology, testing conditions and sampling methods, and updating the instrumental TPA as applied to gelled systems.
Abstract: Instrumental Texture Profile Analysis (TPA) was developed about 30 years ago, constituting an interesting way of analyzing a series of textural parameters in only one test Since then much work has been done and new tools have been developed This paper focuses on gelled food systems, reviewing and discussing the evolution of the initial terminology, testing conditions and sampling methods New parameters, experimental and calculation methods, and some newly proposed are also analyzed, updating the instrumental TPA as applied to gelled systems
TL;DR: Results indicate the presence of a putative nitric oxide synthase in plants, which was synthesized by roots and nodules of Lupinus albus in an l‐arginine‐dependent manner.
TL;DR: Araucan and Caupolican appear to be positive, direct regulators of ac-sc, members of a novel family of homeoproteins, with homologs in vertebrates.
TL;DR: It is observed that TGF-beta itself can stimulate the expression of endoglin in cultured human monocytes and in the U-937 monocytic line, and this should increase the understanding of the complex pathways which mediate the effects of this factor.
Abstract: Endoglin is a homodimeric membrane glycoprotein which can bind the beta 1 and beta 3 isoforms of transforming growth factor-beta (TGF-beta). We reported previously that endoglin is upregulated during monocyte differentiation. We have now observed that TGF-beta itself can stimulate the expression of endoglin in cultured human monocytes and in the U-937 monocytic line. To study the functional role of endoglin, stable transfectants of U-937 cells were generated which overexpress L- or S- endoglin isoforms, differing in their cytoplasmic domain. Inhibition of cellular proliferation and downregulation of c-myc mRNA which are normally induced by TGF-beta 1 in U-937 cells were totally abrogated in L-endoglin transfectants and much reduced in the S-endoglin transfectants. Inhibition of proliferation by TGF-beta 2 was not altered in the transfectants, in agreement with the isoform specificity of endoglin. Additional responses of U-937 cells to TGF-beta 1, including stimulation of fibronectin synthesis, cellular adhesion, platelet/endothelial cell adhesion molecule 1 (PECAM-1) phosphorylation, and homotypic aggregation were also inhibited in the endoglin transfectants. However, modulation of integrin and PECAM-1 levels and stimulation of mRNA levels for TGF-beta 1 and its receptors R-I, R-II, and betaglycan occurred normally in the endoglin transfectants. No changes in total ligand binding were observed in L-endoglin transfectants relative to mock, while a 1.5-fold increase was seen in S-endoglin transfectants. The degradation rate of the ligand was the same in all transfectants. Elucidating the mechanism by which endoglin modulates several cellular responses to TGF-beta 1 without interfering with ligand binding or degradation should increase our understanding of the complex pathways which mediate the effects of this factor.
TL;DR: In this article, the authors used torsion tests to determine the Zener-Hollomon parameter in a selection of 18 steels with compositions appropriate for the study of the influence of each alloying element (C, Mn, Si, Mo, Ti, V, Nb).
TL;DR: In the presence of economies of scale, depositors' expectations are shown to give rise to vertical differentiation and to yield multiple market equilibria, some of which exhibit institutional or systemic collapse.
01 Jan 1996
TL;DR: Darwin’s book on orchids evoked a major revolution in botany and gave rise to an enormous literature on pollination ecology, and marked the starting point for a tradition in the practice of pollination biology.
Abstract: Certain natural history phenomena may provide a vivid illustration of selection in action and its adaptive products, and nearly every evolutionary biologist would agree that the pollination of flowers by animals provides a most illustrative example. It was surely not by chance that the first of Darwin’s books to be published after The Origin of Species was precisely his treatise on the “contrivances by which orchids are fertilised by insects” (Darwin, 1862), the first in a series of monographs aimed at providing detailed supporting evidence for the theory of natural selection. Darwin’s book on orchids evoked a major revolution in botany and gave rise to an enormous literature on pollination ecology (Ghiselin, 1984). It also marked the starting point for a tradition in the practice of pollination biology.
TL;DR: In this paper, an analysis of the electroweak phase transition in the Minimal Supersymmetric Standard Model, in the presence of light stops, has been performed and it has been shown that the order parameter v(Tc)/Tc can become significantly larger than one, for values of the Higgs and supersymmetric particle masses consistent with the present experimental bounds.
TL;DR: The crystal structure of the DNA-binding domain of RAP1 in complex with telomeric DNA site at 2.25 A resolution provides insight into the recognition of the conserved telomersic DNA sequences by a protein.
TL;DR: It is numerically show that the synchronization of two chaotic semiconductor lasers is possible when a small amount of output intensity from one is injected into the other and a message can be encoded in the chaotic carrier and transmitted by an optical fiber and decoded by a receiver with a very good quality.
Abstract: We numerically show that the synchronization of two chaotic semiconductor lasers is possible when a small amount of output intensity from one Is injected into the other. We also show that a message can be encoded in the chaotic carrier, transmitted by an optical fiber and decoded by a receiver with a very good quality.
TL;DR: Inhibition of protein synthesis correlates with eIF‐2α phosphorylation in response to a wide variety of different stimuli, including heat shock, serum deprivation, glucose starvation, amino acid starvation, exposure to heavy metal ions, and viral infection.
Abstract: Protein synthesis is regulated in response to environmental stimuli by covalent modification, primarily phosphorylation, of components of the translational machinery. Phosphorylation of the alpha subunit of eIF-2 is one of the best-characterized mechanisms for down-regulating protein synthesis in higher eukaryotes in response to various stress conditions. Three distinct protein kinases regulate protein synthesis in eukaryotic cells by phosphorylating the alpha subunit of eIF-2 at serine-51. There are two mammalian eIF-2alpha kinases: the double-stranded RNA-dependent kinase (PKR) and heme-regulated inhibitor kinase (HRI), and the yeast GCN2. The regulatory mechanisms and the molecular sizes of these eIF-2alpha kinases are different. The expression of PKR is induced by interferon, and the kinase activity is stimulated by low concentrations of double-stranded RNA. HRI is activated under heme-deficient conditions. Yeast GCN2 is activated by amino acid starvation. The phosphorylation of eIF-2alpha results in the shutdown of protein synthesis. Nevertheless, the eIF-2alpha kinases can regulate both global as well as specific mRNA translation. Inhibition of protein synthesis correlates with eIF-2alpha phosphorylation in response to a wide variety of different stimuli, including heat shock, serum deprivation, glucose starvation, amino acid starvation, exposure to heavy metal ions, and viral infection. Finally, recent studies suggest a role for eIF-2alpha phosphorylation in the control of cell growth and differentiation.