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Strong Dependency (strong + dependency)
Selected AbstractsHabitat shifts of endangered species under altered climate conditions: importance of biotic interactionsGLOBAL CHANGE BIOLOGY, Issue 11 2008KRISTINE L. PRESTON Abstract Predicting changes in potential habitat for endangered species as a result of global warming requires considering more than future climate conditions; it is also necessary to evaluate biotic associations. Most distribution models predicting species responses to climate change include climate variables and occasionally topographic and edaphic parameters, rarely are biotic interactions included. Here, we incorporate biotic interactions into niche models to predict suitable habitat for species under altered climates. We constructed and evaluated niche models for an endangered butterfly and a threatened bird species, both are habitat specialists restricted to semiarid shrublands of southern California. To incorporate their dependency on shrubs, we first developed climate-based niche models for shrubland vegetation and individual shrub species. We also developed models for the butterfly's larval host plants. Outputs from these models were included in the environmental variable dataset used to create butterfly and bird niche models. For both animal species, abiotic,biotic models outperformed the climate-only model, with climate-only models over-predicting suitable habitat under current climate conditions. We used the climate-only and abiotic,biotic models to calculate amounts of suitable habitat under altered climates and to evaluate species' sensitivities to climate change. We varied temperature (+0.6, +1.7, and +2.8 °C) and precipitation (50%, 90%, 100%, 110%, and 150%) relative to current climate averages and within ranges predicted by global climate change models. Suitable habitat for each species was reduced at all levels of temperature increase. Both species were sensitive to precipitation changes, particularly increases. Under altered climates, including biotic variables reduced habitat by 68,100% relative to the climate-only model. To design reserve systems conserving sensitive species under global warming, it is important to consider biotic interactions, particularly for habitat specialists and species with strong dependencies on other species. [source] Experimental and computational tools useful for (re)construction of dynamic kinase,substrate networksPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 23 2009Chris Soon Heng Tan Abstract The explosion of site- and context-specific in vivo phosphorylation events presents a potentially rich source of biological knowledge and calls for novel data analysis and modeling paradigms. Perhaps the most immediate challenge is delineating detected phosphorylation sites to their effector kinases. This is important for (re)constructing transient kinase,substrate interaction networks that are essential for mechanistic understanding of cellular behaviors and therapeutic intervention, but has largely eluded high-throughput protein-interaction studies due to their transient nature and strong dependencies on cellular context. Here, we surveyed some of the computational approaches developed to dissect phosphorylation data detected in systematic proteomic experiments and reviewed some experimental and computational approaches used to map phosphorylation sites to their effector kinases in efforts aimed at reconstructing biological signaling networks. [source] Chirality Transfer in Imidazolium Camphorsulfonate Ionic Liquids through Ion Pairing EffectsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009Karola Schneiders Abstract The paper describes our studies on ion pair interactions in ionic liquids (IL) using an asymmetric hydrogenation reaction as probe. Three different ionic liquids carrying prochiral keto-functionalized cations were hydrogenated in the presence of their chiral, enantiomerically pure counter-ion using an achiral heterogeneous ruthenium catalyst. For the hydrogenation of N -(3,-oxobutyl)- N -methylimidazolium camphorsulfonate (2), N -(3,-oxobutyl)imidazolium camphorsulfonate (4) and N -(5,-oxohexyl)- N -methylimidazolium camphorsulfonate (6) we found a strong dependency of the enantiomeric excess (ee in the cation) on the polarity of the solvent, the concentration of the IL and the structure of the IL. The highest ee values of up to 94% were found for the hydrogenation of 2 in ethanol. Interestingly, we observed that the ee (and consequently the strength of ion pair interaction) had a pronounced maximum for a certain concentration of the IL in the solvent depending on the nature of the solvent and on the substrate. Remarkably, the concentration leading to the maximum ee could be rationalized by independent determination of the degree of dissociation which was obtained by a combination of diffusion-ordered NMR spectroscopy and conductivity measurements. [source] Comparison of mechanical properties of PP/SEBS blends at intermediate and high strain rates with SiO2 nanoparticles vs.JOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008CaCO3 fillers Abstract The present article focuses on the effect of two types of inorganic fillers (SiO2 and CaCO3) on the mechanical properties of PP/SEBS blend. The nominal particle diameters of SiO2 and CaCO3 are 7 nm and 1 ,m, respectively. The studied blend ratios were PP/SEBS/SiO2 (CaCO3) = 75/22/3 and 73/21/6 vol %. The morphology of polymer blends was observed and the distributions of the SEBS, SiO2, and CaCO3 particles were analyzed by transmission electron microscopy (TEM). Tensile tests were conducted at nominal strain rates from 3 × 10,1 to 102 s,1. The apparent elastic modulus has the local strain-rate dependency caused by SiO2 nanoparticles around SEBS particles in the blend of PP/SEBS/SiO2. The yield stress has weak dependency of morphology. The absorbed strain energy has strong dependency of the location of SiO2 nanoparticle or CaCO3 fillers and SEBS particle in the morphology. It is considered that such morphology, in which inorganic nanoparticles are located around SEBS particles, can prevent the brittle fracture while the increased local strain rate can enhance the apparent elastic modulus of the blend at the high strain rate. On the basis of the results of this study, the location and size of inorganic nanoparticles are the most important parameters to increase the elastic modulus without decreasing the material ductility of the blend at both low and high strain rates. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Raman scattering of vanadium ladder compounds from first principlesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2004J. Spitaler Abstract We investigate phonon Raman scattering of the Ag modes in NaV2O5 and CaV2O5. We perform firstprinciples calculations within density functional theory (DFT) to obtain the ground state with relaxed atomic positions. Thereupon we determine eigenvectors and frequencies of the 8 Ag modes within the frozen phonon approach and compute the dielectric functions ,(,) for structures distorted according to the phonon eigenvectors. Raman intensities are obtained using the derivatives of ,(,) with respect to the normal coordinates Q taken at the incident photon energy ,I. For NaV2O5 the peak positions and the relative intensities of the theoretical results for the experimentally used frequency ,I = 2.5 eV excellently agree with measured data. Moreover, for the three different scattering geometries a strong dependency of the Raman intensity on ,I is revealed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High Productive Deposited Mo Layers for Back Ohmic Contacts of Solar CellsPLASMA PROCESSES AND POLYMERS, Issue S1 2009Jens-Peter Heinß Abstract In the paper, thin molybdenum (Mo) layers produced by magnetron sputtering [state of the art in production for photovoltaic applications (PV)] are compared with those produced by high-rate electron beam (EB) deposition technology. Stainless steel and borofloat glass served as substrate materials. Mo layers deposited by DC-magnetron sputtering were produced as a reference and investigated by analysis of structure and specific electrical resistance. Alternative layers prepared by high-rate EB-deposition with a rate up to 240,nm·s,1 were characterised by inquests of mechanical properties, sheet resistance and cell efficiency. A strong dependency of specific electrical resistance on residual gas conditions was determined. The specific electrical resistance dropped from 18 to 11,µ,·cm. Compactness of Mo layers increased with implementation of plasma activation. The layer formation became denser and comparable to the magnetron sputtered Mo layers. [source] Atmospheric Pressure Plasma Deposition of Adhesion Promotion Layers on AluminiumPLASMA PROCESSES AND POLYMERS, Issue S1 2009Philipp Bringmann Abstract The paper presents investigations on the deposition of plasma polymerised films at atmospheric pressure as a pretreatment for painting and adhesive bonding of aircraft aluminium structures. Two different plasma jet sources are employed, one based on a controlled arc discharge and air as process gas, and another based on a dielectric barrier discharge (DBD) and He as plasma gas. The organosilicon precursors HMDSO, TEOS and OMCTS are used with both plasma sources. Deposition in the arc discharge plasma jet leads to almost carbon-free silica coatings, whereas coatings deposited with the DBD jet source contain a high amount of carbon, varying with precursor type. The obtained results of corrosion investigations and adhesion tests are promising, as some representative aircraft industry requirements could be achieved. However, the investigations show a strong dependency on the used precursor and type of polymer (paint or adhesive) applied on the plasma polymerised film. [source] Evaluation of the interfacial state in high impact polystyrene through dynamic mechanical analysis as a function of the synthesis conditions,POLYMER ENGINEERING & SCIENCE, Issue 11 2007R. Díaz de León High impact polystyrene was synthesized using two series of styrene/butadiene (SB) tapered block copolymers with a polystyrene (PS)/polybutadiene (PB) composition of 30/70 and 10/90 wt%. During the synthesis, concentration of initiator, SB and transfer agent were varied. From dynamic mechanical analysis, the corresponding , relaxation of the rubber phase was detected at low temperature (near ,100°C) and that of the glassy PS phase at high temperature (near 100°C). Also, another relaxation at temperature near 40°C was identified, which was associated to the , relaxation of the glassy PS phase. The variations found in the , relaxation of the rubber phase, were attributed to changes in the morphological structure as a consequence of variation in initiator, SB or transfer agent concentrations and in SB composition. , relaxation showed a strong dependency with the interfacial state between the rubber and the glassy phase, where an increase in the amount of graft PS at the interface, which promotes the interfacial adhesion between phases, causes an increase in the magnitude of , relaxation of the PS phase. The results were attributed to variations in the interfacial area as a result of the change in the particle size and to the contribution of molecular chains of each phase in participating in the relaxation process. POLYM. ENG. SCI., 47:1827,1838, 2007. © 2007 Society of Plastics Engineers [source] Interlaminar contact development during thermoplastic fusion bondingPOLYMER ENGINEERING & SCIENCE, Issue 2 2002F. Yang Fabrication of layered thermoplastics and thermoplastic-matrix composites using processes such as tow placement, tape laying, and resistance welding is fundamentally based on the principle of fusion bonding, which involves applying heat and pressure to contacting thermoplastic surfaces. One of the important processing steps,intimate contact development,is considered in this paper. Interlaminar intimate contact development has a strong dependency on the thermoplastic surface geometry. Profilometric measurements of common thermoplastic prepreg tows, such as AS4/PEEK and IM7/PIXA, show that surface roughness features appear at several length scales and that the surfaces have fractal asperity structures. In this paper, principles of fractal geometry are used to describe prepreg surfaces. Based on this description, a microscale fluid flow model is developed to relate a degree of intimate contact to the process parameters (pressure, temperature, and time) and the fractal parameters of the surface. The model development and comparisons with experimental data are presented and discussed. [source] | |||||||||||||