The specific interfacial area in external-loop airlift bioreactors

The specific interfacial areas in two external-loop airlift bioreactors of laboratory and pilot scale were determined, mainly by the chemical reaction method (sulphite oxidation). The parameter studied in water/salt and starch/salt solutions was greately affected by gas superficial velocity, A _D /A _R ratio, by H _R ?H _D /H _D ratio and η _ap , respectively. Correlations for the specific interfacial area in the two systems, considering the effects of the above-mentioned parameters, were proposed.     

Growth process and interfacial process considered in connection with specific surface area

Analytical expressions for the radius of gyration and maximum dimension of compound bodies formed from simple geometric elements are derived. Using principles of symmetry and of commonly observed features of globular protein structures, it is shown how a priori reasonable tertiary and quaternary structures can be distinguished. The formulae, which are simple to apply, permit a rapid comparison of relatively complex shapes, so reducing the amount of computation necessary for a detailed analysis of small angle scattering data. In conjunction with other biophysical data, the morphological parameters derived from scattering curves can be used to generate quite complex biologically reasonable models of protein structures.     

An empirical evaluation of spatial value transfer methods for identifying cultural ecosystem services

A significant barrier to the assessment of ecosystem services is a lack of primary data, especially for cultural ecosystem services. Spatial value transfer, also known as benefits transfer, is a method to identify the probable locations of ecosystem services based on empirical spatial associations found in other geographic locations. To date, there has been no systematic evaluation of spatial value transfer methods for cultural ecosystem services identified through participatory mapping methods. This research paper addresses this knowledge gap by examining key variables that influence value transfer for cultural ecosystem services: (1) the geographic setting, (2) the type of ecosystem services, and (3) the land cover data selected for value-transfer. Spatial data from public participation GIS (PPGIS) processes in two regions in Norway were used to evaluate spatial value transfer where the actual mapped distribution of cultural ecosystem values were compared to maps generated using value transfer coefficients. Six cultural ecosystem values were evaluated using two different land cover classification systems GlobCover (300 m resolution) and CORINE (100 m resolution). Value transfer maps based on the distribution of mapped ecosystem values produced strongly correlated results to primary data in both regions. Value transfer for cultural ecosystems appear valid under conditions where the primary data and value transfer regions have similar physical landscapes, the social and cultural values of the human populations are similar, and the primary data sample sizes are large and unbiased. We suggest the use of non-economic value transfer coefficients derived from participatory mapping as the current best approach for estimating the importance and spatial distribution of cultural ecosystem services.     

Finding complex oscillatory phenomena in biochemical systems. An empirical approach

Starting with a model for a product-activated enzymatic reaction proposed for glycolytic oscillations, we show how more complex oscillatory phenomena may develop when the basic model is modified by addition of product recycling into substrate or by coupling in parallel or in series two autocatalytic enzyme reactions. Among the new modes of behavior are the coexistence between two stable types of oscillations (birhythmicity), bursting, and aperiodic oscillations (chaos). On the basis of these results, we outline an empirical method for finding complex oscillatory phenomena in autonomous biochemical systems, not subjected to forcing by a periodic input. This procedure relies on finding in parameter space two domains of instability of the steady state and bringing them close to each other until they merge. Complex phenomena occur in or near the region where the two domains overlap. The method applies to the search for birhythmicity, bursting and chaos in a model for the cAMP signalling system of Dictyostelium discoideum amoebae.     

An empirical approach for deriving specific inland water quality parameters from high spatio-spectral resolution image

Inland lake of Vembanad has benefited from continuous monitoring to evaluate water quality which has declined due to increased anthropogenic activities and climate change. Remote sensing techniques can be used to estimate and monitor inland water quality both spatially and temporally. An empirical model is presented in Vemaband lake that retrieves the specific water quality parameters through correlations between various spectral wavelengths of Sentinel-2MSI (S2MSI) with field-measured water quality parameters. This approach includes the combinations of various bands, band ratios, and band arithmetic computation of satellite sensors of spectral datasets. The specific inland water quality parameters such as chlorophyll-a (chl-a), total suspended solids (TSS), turbidity, and secchi disc depth (SDD) were retrieved from the developed water quality model through Sentinel-2A remote sensing reflectance. The result illustrates that Specific Inland Water Quality Parameters (SIWQP) strongly correlated with S2MSI reflection spectral wavelengths. The SIWQP models are constructed for TSS (R²?=?0.8008), Chl-a (R²?=?0.8055), Turbidity (R²?=?0.6329) and SDD (R²?=?0.7174).The spatial distribution of SIWQPs in Vembanad lake for March 2018 is mapped and shows the lake's water quality distribution. The research from Sentinel-2, MSI has potential and is appropriate in high spectral and spatial characteristics for retrieving and continuous monitoring of water quality parameters in the regional scale of inland water bodies.

     

An approximation diffusion equation for a long narrow channel with varying cross-sectional area

The diffusion equation for long narrow channels which lie parallel to a rectangular coordinate and have varying cross-sectional areas may be approximated by an equation which involves only one space variable and the average concentration at each value of this space variable. This equation is derived and is discussed along with its assumptions.     

Oxygen transfer in mechanically agitated aqueous systems containing dispersed hydrocarbon

The effect of dispersed n -dodecane or n -hexadecane on the air-to-aqueous phase overall volumetric oxygen transfer coefficient in a simulated (cell-free) stirred-tank fermentor is described. The oil volume fraction ranged from zero to 0.10; the ionic strength of the aqueous phases was varied from 0 to 0.45. The air-to-aqueous phase coefficients in both oil-free (K_La) and oil-bearing (K_La*) systems were evaluated from unsteady-state experiments using a membrane-covered probe to follow the aqueous phase dissolved oxygen tension. For all systems studied, K_La*/K_La was found to be independent of P/V and v_s for all practical purposes. However, for a particular aqueous phase and at a given P/V and v_s, the ratio K_La*K_La generally differed from unity. Depending on the combination of hydrocarbon type and volume fraction and the aqueous-phase ionic strength employed, the dispersed hydrocarbon may, in some cases, reduce the rate of oxygen transfer and in others enhance it relative to that of the corresponding oil-free gas–liquid dispersion. Enhancement of the air-to-aqueous transfer rate by such negative spreading coefficient hydrocarbons has not been reported previously.     

An empirical method for the evaluation of the quality of genomic DNA libraries.

An empirical method is presented that enables one to determine, with only a relatively small investment of time and materials, whether a lambda genomic DNA library will be a productive source of clones carrying specific sequences. The method provides an indication of the abundance of the sequences in library DNA and indicates whether major DNA rearrangements have occurred during library construction and amplification.     

An empirical evaluation of instantaneous and one-zero sampling of chimpanzee behavior

The behavior category in progress at theend of every 15 seconds of observation of chimpanzee behavior was recorded (instantaneous sampling) as was the occurrence or nonoccurrence of all defined categoriesduring every 15 second observation interval (one-zero sampling). The scores obtained using the above procedures were then correlated with the percent of net observation time, hourly rate, and mean bout duration of the behavior categories. One-zero sampling scores correlated very strongly with percent of net observation time and moderately with hourly rate and mean bout duration. Instantaneous sampling scores correlated very strongly with percent of net observation time and moderately with hourly rate and mean bout duration.     

Ultrafast interfacial solvation dynamics in specific protein DNA recognition

An overwhelming number of structural and functional studies on specific protein–DNA complexes reveal the existence of water molecules at the interaction interface. What role does the interfacial water molecules play in determining the specificity of association is thus a critical question. Herein, we have explored the dynamical role of minor groove water molecules and DNA side chain flexibility in lambda repressor–operator DNA interaction using well-characterized DNA minor groove binder dye, Hoechst 33258. The most striking finding of our studies reveals that the solvation time scale corresponding to the minor groove water molecules (∼50 ps) and DNA side chain flexibility (∼10 ns) remain unaltered even in protein–DNA complex in comparison to unbound operator DNA. The temperature dependent study further reveals the slower exchange of minor grove water molecules with bulk water in DNA–protein complex in comparison to the unbound DNA. Detailed structural studies including circular dichroism (CD) and Förster resonance energy transfer (FRET) have also been performed to elucidate the interaction between protein and DNA.     

Inhomogeneous interfacial regions of biological systems

On the premise that the contributions from ion-ion interaction energy terms to chemical potential of an ion in inhomogeneous regions cannot be neglected, the classical expression for electrochemical potential is modified. Resulting basic differential equations and their implications regarding ion distributions in inhomogeneous regions are presented. It is shown that a necessary consequence is the existence of a dielectric profile in inhomogeneous regions due to nonvanishing interaction energy terms of the chemical potential.     

An empirical relationship between rotational correlation time and solvent accessible surface area

Structure–dynamics interrelationships are important in understanding protein function. We have explored the empirical relationship between rotational correlation times (_c and the solvent accessible surface areas (SASA) of 75 proteins with known structures. The theoretical correlation between SASA and _c through the equation SASA = K_rc ^(2/3) is also considered. SASA was determined from the structure, _c ^calc was determined from diffusion tensor calculations, and _c ^expt was determined from NMR backbone¹³ C or ¹⁵N relaxation rate measurements. The theoretical and experimental values of _c correlate with SASA with regression analyses values of K_r as 1696 and 1896 m²s^-(2/3), respectively, and with corresponding correlation coefficients of 0.92 and 0.70.     

An empirical relationship between rotational correlation time and solvent accessible surface area

Structure–dynamics interrelationships are important in understanding protein function. We have explored the empirical relationship between rotational correlation times (τ_c and the solvent accessible surface areas (SASA) of 75 proteins with known structures. The theoretical correlation between SASA and τ_c through the equation SASA = K_rτ_c ^(2/3) is also considered. SASA was determined from the structure, τ_c ^calc was determined from diffusion tensor calculations, and τ_c ^expt was determined from NMR backbone¹³ C or ¹⁵N relaxation rate measurements. The theoretical and experimental values of τ_c correlate with SASA with regression analyses values of K_r as 1696 and 1896 m²s^-(2/3), respectively, and with corresponding correlation coefficients of 0.92 and 0.70.     

Background yield of phosphorus from drainage area and atmosphere: An empirical approach

The role of phosphorus in the eutrophication of lakes and marine coastal areas has created a need of more information on the size of a virgin background supply of phosphorus.The general pollution of the atmosphere has resulted in an increased amount of anthropogenic phosphorus in air masses over remote ocean areas in the Northern Hemisphere. As a consequence this applies also to remote land areas, where the phosphorus deposition of about 5 kg P km^-2 a^-1 may seem to be 2–3 times the virgin phosphorus deposition.The present background drainage basin yield of phosphorus is also elevated due to a general eutrophication of the terrestrial ecosystem. The background supply varies due to several factors of which drainage basin size, geology and vegetation are discussed. Background yields apparently have a range from 3–10 kg P km^-2 a^-1.