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Remarkable Features (remarkable + feature)
Selected AbstractsClimate of the seasonal cycle in the North Pacific and the North Atlantic oceansINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 4 2001Igor M. Yashayaev Abstract Time series of monthly sea-surface temperature (SST), air temperature (AT) and sea level pressure (SLP) were constructed from merged releases of the Comprehensive Ocean-Atmosphere Data Set (COADS). The time series were decomposed into seasonal and non-seasonal (short and long-term) components. The contribution of the seasonal cycle to the total variance of SST and AT exceeds 80% in the mid and in some high latitude locations and reaches its peak (>95%) in the centres of subtropical gyres. In most cases, a combination of annual and semiannual harmonics accounts for more than 95% of the seasonal variability. Amplitudes of SST and AT annual cycles are highest near the western boundaries of the oceans; annual phases of SST and AT increase toward the eastern tropical oceans, revealing a southeastern propagation of the annual cycle over the Northern Hemisphere oceans. The annual cycle of AT leads that of SST by 1,3 weeks. The largest phase differences are observed in the regions of western boundary currents in the North Pacific and the North Atlantic oceans. This is consistent with spatial patterns of integral air,sea heat fluxes. Annual phases of SST increase along the Gulf Stream and the Kuroshio Current. This points to the importance of signal transport by the major ocean currents. The lowest annual amplitudes of SLP are observed along the equator (0°,10°N) in both oceans. There are three distinct areas of high annual amplitudes of SLP in the North Pacific Ocean: Asian, Aleutian and Californian. Unlike the North Pacific, only one such area exists in the North Atlantic centred to the west of Iceland. A remarkable feature in the climate of the North Pacific is a maximum of semiannual SLP amplitudes, centred near 40°N and 170°W. It is also an absolute maximum in the entire Northern Hemisphere. Analysis of phases of harmonics of SLP seasonal cycle has revealed the trajectories of propagation of the annual and semiannual cycles. Analysis of semiannual to annual amplitudes ratio has revealed the regions of semiannual cycle dominance. Copyright © 2001 Royal Meteorological Society [source] Mechanism for Salt ScalingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2006John J. Valenza II Over the past 60 years, concrete infrastructure in cold climates has deteriorated by "salt scaling," which is superficial damage that occurs during freezing in the presence of saline water. It reduces mechanical integrity and necessitates expensive repair or replacement. The phenomenon can be demonstrated by pooling a solution on a block of concrete and subjecting it to freeze/thaw cycles. The most remarkable feature of salt scaling is that the damage is absent if the pool contains pure water, it becomes serious at concentrations of a few weight percent, and then stops at concentrations above about 6 wt%. In spite of a wealth of research, the mechanism responsible for this damage has only recently been identified. In this article, we show that salt scaling is a consequence of the fracture behavior of ice. The stress arises from thermal expansion mismatch between ice and concrete, which puts the ice in tension as the temperature drops. Considering the mechanical and viscoelastic properties of ice, it is shown that this mismatch will not cause pure ice to crack, but moderately concentrated solutions are expected to crack. Cracks in the brine ice penetrate into the substrate, resulting in superficial damage. At high concentrations, the ice does not form a rigid enough structure to result in significant stress, so no damage occurs. The morphology of cracking is predicted by fracture mechanics. [source] Community structure of bathyal decapod crustaceans off South-Eastern Sardinian deep-waters (Central-Western Mediterranean)MARINE ECOLOGY, Issue 2009Maria Cristina Follesa Abstract Community structure and faunal composition of bathyal decapod crustaceans off South-Eastern Sardinian deep-waters (Central-Western Mediterranean) were investigated. Samples were collected during 32 hauls between 793 and 1598 m in depth over the 2003,2007 period. A total of 1900 decapod specimens belonging to 23 species were collected. Multivariate analysis revealed the occurrence of three faunistic assemblages related to depth: (i) an upper slope community at depths of 793,1002 m; (ii) a middle slope community at depths of 1007,1212 m and (iii) a lower slope community at depths greater 1420 m. In the upper and middle slopes the benthic (Polycheles typhlops) and epibenthic,endobenthic feeders (mainly Aristeus antennatus and Geryon longipes), which eat infaunal prey, were dominant, followed by the macroplankton,epibenthic feeders such as Acanthephyra eximia and Plesionika acanthonotus. In the deepest stratum, the most remarkable feature was the prevalence of macroplankton,epibenthic feeders (A. eximia and P. acanthonotus). A small percentage of the benthic deep-sea lobster Polycheles sculptus was also present. The biomass presented higher values in the middle slope and declined strongly in the lower slope. There was no general pattern of mean individual weight/size versus depth among decapods, and the changes seemed to be species-specific with different trends. [source] Implementing a proximal algorithm for some nonlinear multicommodity flow problemsNETWORKS: AN INTERNATIONAL JOURNAL, Issue 1 2007Adam Ouorou Abstract In this article, we consider applying a proximal algorithm introduced by Ouorou to some convex multicommodity network flow minimization problems. This algorithm follows the characterization of saddle points introduced earlier but can be derived from Martinet's proximal algorithm. In the primal space, the algorithm can be viewed as a regularized version of the projection algorithm by Rosen. A remarkable feature of the algorithm is that the projection step for multicommodity flow problems reduces to solving independent linear systems (one for each commodity) involving the node-arc incidence matrix of the network. The algorithm is therefore amenable to parallel implementation. We present some numerical results on large-scale routing problems arising in telecommunications and quadratic multicommodity flow problems. A comparison with a specialized code for multicommodity flow problems indicates that this proximal algorithm is specially designed for very large-scale instances. © 2006 Wiley Periodicals, Inc. NETWORKS, Vol. 49(1), 18,27 2007 [source] A dimeric 5- enol -pyruvyl-shikimate-3-phosphate synthase from the cyanobacterium Spirulina platensisNEW PHYTOLOGIST, Issue 2 2001Giuseppe Forlani Summary ,,Isolation and biochemical characterization is reported here of 5- enol -pyruvyl-shikimate-3-phosphate (EPSP) synthase, the enzyme that catalyses the sixth step in the common prechorismate pathway of aromatic amino acid biosynthesis and the target of the widely used herbicide glyphosate, from the cyanobacterium Spirulina platensis. ,,Homogeneous enzyme preparations were obtained by ammonium sulphate fractionation, anion-exchange and substrate-elution chromatography, and chromatofocusing. Protein characterization was carried out by conventional kinetic analysis, PAGE and gel permeation. ,,A 2800-fold purification was achieved, with a recovery of 20% of initial activity. Unusually low apparent affinities for both substrates, phosphoenolpyruvate and shikimate-3-phosphate, did not correspond to decreased glyphosate sensitivity. During SDS-PAGE, the protein migrated as a single band corresponding to a molecular mass of c. 49 kDa. The behaviour of the protein upon gel permeation chromatography under nondenaturing conditions was, however, consistent with a mass of c. 91 kDa. ,,The native enzyme appears to be homodimeric, a remarkable feature that has not been previously reported for EPSP synthases from either cyanobacteria or higher plants. The presence of mono- and dimeric EPSP synthases could represent an important tool for cyanobacterial classification. [source] Semiconducting half-Heusler and LiGaGe structure type compoundsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009Frederick Casper Abstract Compounds with LiAlSi (half-Heusler) and LiGaGe structure types have been investigated by means of band structure calculations. The LiAlSi structure type is known as the half-Heusler structure type, whereas LiGaGe is a closely related hexagonal variant. A remarkable feature of some XYZ half-Heusler compounds with 8 and 18 valence electrons is, that despite being composed of only metallic elements, they are semiconductors. More than 100 semiconducting compounds within these structure types are known. LiGaGe compounds have an additional degree of freedom, namely the degree of puckering of the layers. These compounds can become semiconducting at a certain degree of puckering. Half-metallic behavior is rarely found in this structure type. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Chondrocranium and skeletal development of Phrynops hilarii (Pleurodira: Chelidae)ACTA ZOOLOGICA, Issue 4 2009Paula Bona Abstract The present study represents the first comprehensive contribution to the knowledge of the skeletal development of a pleurodiran turtle, Phrynops hilarii (Pleurodira, Chelidae). The most remarkable features found are: (1) absence of ascending process on pterygoquadrate cartilage; (2) presence of ossification centres for the epiotics; (3) as in other pleurodirans, dorsal ribs IX and X are ,sacralized'; (4) contact between ilium and carapace occurs later in ontogenetic development; (5) suture between ischia, pubes and plastron occurs in posthatching specimens; (6) contrary to previous interpretations, the phalangeal formula of the pes of P. hilarii is 2 : 3 : 3 : 3 : 5; (7) the hooked bone represents the fifth metatarsal. [source] Enantioselective Hydrogenation of ,-Dehydroamino Acid Esters Catalyzed by Rhodium Complexes with Chiral Bisaminophosphine LigandsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7 2010Xianfeng Sun Abstract A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium-catalyzed asymmetric hydrogenations of ,-dehydroamino acid esters. Up to 98% ee values were achieved for the enantioselective synthesis of aminocarboxylic acids and their derivatives, which are very important chiral building blocks for the synthesis of a variety of natural products and biologically active molecules. [source] Axial Chirality Control by 2,4-Pentanediol for the Alternative Synthesis of C3*-TunePhos Chiral Diphosphine Ligands and Their Applications in Highly Enantioselective Ruthenium-Catalyzed Hydrogenation of ,-Keto EstersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2009Xianfeng Sun Abstract A highly efficient strategy for the synthesis of a series of C3*-TunePhos chiral diphosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for the ruthenium-catalyzed asymmetric hydrogenation of ,-keto esters. Up to 99% ee values were achieved for the enantioselective synthesis of ,-hydroxy acid derivatives, which are very important chiral building blocks for the synthesis of a variety of natural products and biologically active molecules. [source] Novel jute yarns grafted with methyl methacrylateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2008M. Montazer Abstract This research work involves graft copolymerization of jute fibers with methyl methacrylate (MMA), initiated by cerric ions, and optimization of the grafting parameters as a function of different polymerization conditions. It was considered to produce a hydrophobic jute fiber with enhanced properties. To achieve this, the effects of monomer concentration and grafting percentage on FTIR spectra, mechanical properties, moisture regain, oil-adsorption capacity, and surface morphology were investigated, and optimum percentage of MMA with reasonable properties was suggested. The results indicated that cerric ions initiated graft copolymerization of MMA onto jute with 30% of weight of monomers at optimum conditions of acid concentration and temperature. The FTIR studies proposed grafting of MMA onto jute at hydroxyl groups. The results showed that mechanical properties and moisture regain (%) of samples decrease with increasing of graft percentage. The most remarkable features of this investigation include reducing oil-adsorption capacity with increasing of lipophilic monomer percentages after one limitation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] The hemoglobins of the trematodes Fasciola hepatica and Paramphistomum epiclitum: A molecular biological, physico-chemical, kinetic, and vaccination studyPROTEIN SCIENCE, Issue 10 2008Sylvia Dewilde Abstract The trematode Fasciola hepatica (Fa.he.) is a common parasite of human and livestock. The hemoglobin (Hb) of Fa.he., a potential immunogen, was chosen for characterization in the search for an effective vaccine. Characterization of trematode Hbs show that they are intracellular single-domain globins with the following remarkable features: (1) Fa.he. expresses two Hb isoforms that differ at two amino acid sites (F1: 119Y/123Q; F2: 119F/123L). Both isoforms are monoacetylated at their N-termini; (2) the genes coding for Fa.he. and Paramphistomum epiclitum (Pa.ep.) Hbs are interrupted by two introns at the conserved positions B12.2 and G7.0.; (3) UV/VIS and resonance Raman spectroscopy identify the recombinant Fa.he. HbF2 as a pentacoordinated high-spin ferrous Hb; (4) electron paramagnetic resonance spectroscopy of cyano-met Fa.he. HbF2 proves that the endogenously bound imidazole has no imidazolate character; (5) the major structural determinants of the globin fold are present, they contain a TyrB10/TyrE7 residue pair on the distal side. Although such distal-site pair is a signature for high oxygen affinity, as shown for Pa.ep. Hb, the oxygen-binding rate parameters for Fa.he. Hb are intermediate between those of myoglobin and those of other trematode Hbs; (6) the three-dimensional structure of recombinant Fa.he. HbF2 from this study closely resembles the three-dimensional structure of Pa.ep. determined earlier. The set of distal-site polar interactions observed in Pa.ep. Hb is matched with small but significant structural adjustments; (7) despite the potential immunogenic character of the fluke Hb, vaccination of calves with recombinant Fa.he. HbF2 failed to promote protection against parasitic infection. [source] Anisotropic distribution of quantum-vacuum momentum density in a moving electromagnetic mediumANNALEN DER PHYSIK, Issue 7 2010J.Q. Shen Abstract An isotropic electromagnetic medium becomes gyrotropically anisotropic when it moves, and an anisotropic electromagnetic environment can then be created in this motion-induced anisotropic medium. One of the most remarkable features is that the quantum vacuum in the anisotropic electromagnetic environment exhibits a nonzero electromagnetic momentum density, since the universal symmetry of the vacuum fluctuation field is broken, and the anisotropic quantum vacuum mode structure is produced because of the symmetry breaking. This would give rise to a noncompensation effect among the four vacuum eigenmodes (i.e., the forward and backward propagating modes as well as their respective mutually perpendicular polarized components), and leads to an anisotropic correction to the vacuum momentum in the moving medium. The physical significance and the potential applications of the anisotropic quantum vacuum are discussed. This quantum-vacuum effect may be used to develop sensitive sensor techniques and to design new quantum optical and photonic devices. [source] The Trifluoroethylamine Function as Peptide Bond ReplacementCHEMMEDCHEM, Issue 12 2007Monica Sani Dr. 3D instead of 2D. That's the main difference between the tetrahedral stereogenic trifluoroethylamine function and the planar peptide bond. This property, together with other remarkable features such as high metabolic stability and low basicity, turns out to be of great importance to allow trifluoroethylamines to be excellent peptide bond replacements. 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