			Home About us Contact

Effects Need (effects + need)

Distribution by Scientific Domains

Chemistry	40%

Selected Abstracts

Evaluating local hydrological modelling by temporal gravity observations and a gravimetric three-dimensional model

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2010
M. Naujoks
SUMMARY An approach for the evaluation of local hydrological modelling is presented: the deployment of temporal terrestrial gravity measurements and gravimetric 3-D modelling in addition to hydrological point observations. Of particular interest is to what extent such information can be used to improve the understanding of hydrological process dynamics and to evaluate hydrological models. Because temporal gravity data contain integral information about hydrological mass changes they can be considered as a valuable augmentation to traditional hydrological observations. On the other hand, hydrological effects need to be eliminated from high-quality gravity time-series because they interfere with small geodynamic signals. In areas with hilly topography and/or inhomogeneous subsoil, a simple reduction based on hydrological point measurements is usually not sufficient. For such situations, the underlying hydrological processes in the soil and the disaggregated bedrock need to be considered in their spatial and temporal dynamics to allow the development of a more sophisticated reduction. Regarding these issues interdisciplinary research has been carried out in the surroundings of the Geodynamic Observatory Moxa, Germany. At Moxa, hydrologically induced gravity variations of several 10 nm s,2 are observed by the stationarily operating superconducting gravimeter and by spatially distributed and repeated high-precision measurements with transportable relative instruments. In addition, hydrological parameters are monitored which serve as input for a local hydrological catchment model for the area of about 2 km2 around the observatory. From this model, spatial hydrological variations are gained in hourly time steps and included as density changes of the subsoil in a well-constrained gravimetric 3-D model to derive temporal modelled gravity variations. The gravity variations obtained from this combined modelling correspond very well to the observed hydrological gravity changes for both, short period and seasonal signals. From the modelling the amplitude of the impact on gravity of hydrological changes occurring in different distances to the gravimeter location can be inferred. Possible modifications on the local hydrological model are discussed to further improve the quality of the model. Furthermore, a successful reduction of local hydrological effects in the superconducting gravimeter data is developed. After this reduction global seasonal fluctuations are unmasked which are in correspondence to GRACE observations and to global hydrological models. [source]

Abnormal salt effects on reactions between ions: The coupling of salt and solvent effects

INTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 9 2009
V. I. Martin
Salt effects on the reactions [Fe(CN)6]4, + S2O=8 and [Ru(NH3)5py]2+ + S2O have been studied in media of different dielectric constants constituted by mixtures of water with organic cosolvents. It is known that salt and solvent effects are coupled and, consequently, cannot be treated separately. This implies that salt (and solvent) effects need to be carefully analyzed before using them as a tool for mechanistic discrimination. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 582,588, 2009 [source]

Examining Situationally Induced State Goal Orientation Effects on Task Perceptions, Performance, and Satisfaction: A Two-Dimensional Conceptualization,

JOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 2 2008
Debra Steele-Johnson
We examined the longitudinal effects of situationally induced 2-dimensional state goal orientations (i.e., achievement goals) on perceptions, performance, and satisfaction. Results (N = 268) indicated that high state learning cues led to higher perceived challenge and, for higher ability individuals, greater performance gains. Further, high state performance cues led to higher perceived effort. However, results revealed that state learning and performance effects were more complex than expected. State learning effects on challenge and state performance effects on effort were both stronger with other cues absent. Additionally, increasingly beneficial state learning cue effects were stronger for higher ability individuals. Thus, results provided support that state learning and performance goals are separate dimensions, and their interactive effects need further examination. [source]

Matrix/analyte ratio influencing polymer molecular weight distribution in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2009
Gitta Schlosser
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been used to characterize poly(L-lysine) polymers and unique oligomer peptides, like 10-, 15- and 25-mer [Lys]n oligolysine peptides. Several matrices have been tried in order to find optimal conditions, but only , -cyano-4-hydroxycinnamic acid gave analytically useful spectra. The synthetic oligomers and their mixtures gave good quality spectra, showing protonated and cationized molecules, including doubly charged species. The polymers, analogously, gave a wide distribution of single- and double-cationized peak series. The polymer distributions observed indicate the presence of significant suppression effects. The concentration (matrix/analyte ratio) was found to influence the results significantly; distributions shifting to higher masses when higher polymer concentrations were used. This effect was studied in detail using the synthetic (,monodisperse') oligolysine peptides. It was found that the relative intensities change by over an order of magnitude in the 0.1,10,pmol/µL concentration range (typical for most proteomic analyses). The results indicate that concentration effects need to be considered when MALDI-MS is used for quantitative purposes. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Sperm Cryopreservation in Brown Bear (Ursus arctos): Preliminary Aspects

REPRODUCTION IN DOMESTIC ANIMALS, Issue 2008
L Anel
Contents The development of sperm cryopreservation procedures in brown bear is the basis for establishing a specific genetic resource bank aimed at the preservation of a Cantabric brown bear population, which is seriously threatened. Several issues complicate the development of these cryopreservation procedures: lack of previous specific studies, a high incidence of urospermia and spermagglutination observed in bear ejaculates. Moreover, the availability of individuals for research from these threatened populations is problematic. In the case of the Cantabric brown bear, we have used males from other populations, but of the same species, as surrogates, to carry out a direct extrapolation of the results. Urospermia , Moreover, 70% of the ejaculates are urine contaminated and spermagglutination have a detrimental effect on post-thawing cell quality recovery in this species. Considering the high value of these samples (autochthonous population with few individuals), a pre-selection of the ejaculates is not a viable alternative. Preventive methods reducing the mentioned detrimental effects need to be developed. On the basis of previous data, we can suppose that bear spermatozoa resist freezing injuries well. Nevertheless, because of the scarcity of this information, it is necessary to conduct further research on bear semen freezing under field conditions. Epidydimal spermatozoa can be important for genetic resource banking of threatened populations and thus specific cryobiological protocols need to be assayed. To date, 168 brown bear ejaculates have been frozen by the ITRA-ULE group at the University of León (Spain) in the development of methodologies for the preservation of brown bear sperm. [source]