Nonlinear Increase (nonlinear + increase)

Distribution by Scientific Domains

Selected Abstracts

Latitudinal patterns in abundance and life-history traits of the mole crab Emerita brasiliensis on South American sandy beaches

Omar Defeo
ABSTRACT Demographic and life-history attributes of the mole crab Emerita brasiliensis were analysed along 2700 km of the Atlantic coast of South America, including sandy beaches at the southernmost limit (Uruguay) and at the core of its geographical range (Brazil). Population features varied markedly within this range and exhibited systematic geographical patterns of variation. Abundance significantly increased from temperate to subtropical beaches, and the same held true for the asymptotic weight of males. Conversely, length at maturity and asymptotic weight of females increased from subtropical to temperate beaches, being inversely related to sea water temperature. Macroecological patterns in abundance and body weight showed the first large-scale evidence of scaling of population density to body size for a sandy beach population. Mortality rates (both sexes) followed a nonlinear increase from low-density temperate beaches to high-density subtropical beaches. The effect of habitat quality and availability could explain discontinuities in the species distribution within its range, and also differential responses in life-history attributes at a local scale. Asymmetries and converse latitudinal trends between sexes suggest that there is not a single general factor determining large-scale patterns in life-history traits of this species. Our results reinforce the view that density-dependent and environmental factors operating together regulate sandy beach populations. The need to develop macroecological studies in sandy beach ecology is highlighted, as knowledge acquired from local to large spatial scales throws light on population structure and regulation mechanisms. [source]

Organometallic Complexes for Nonlinear Optics.


An alkynylruthenium dendrimer exhibits two-photon absorption behavior below 1000,nm, and a nonlinear increase in nonlinearity upon dendrimer growth. Beyond 1000,nm, it undergoes 3PA-induced photochemistry. Its nonlinear optical performance is an order of magnitude greater than that of similar organic dendrimers, demonstrating the performance enhancement possible upon incorporation of metal centers into a molecular architecture. [source]

Independent Effects of Nitrogen Substitution for Oxygen and Yttrium Substitution for Magnesium on the Properties of Mg-Y-Si-Al-O-N Glasses

Michael J. Pomeroy
Glasses of composition (in equivalent percent) (28 ,x)Mg:xY:56Si:16Al:(100 ,y)O:yN, with x= 0, 14, or 28 for y= 0 and 15 and with x= 0, 7, 14, 21, or 28 for y= 10, were prepared by melting and casting. For glasses where the nitrogen content was varied for a constant cationic ratio, the glass molar volume (MV), compactness (C), Young's modulus (E), glass-transition temperature (Tg), and dilatometric-softening temperature (Tds) varied linearly as the nitrogen content increased, with MV decreasing and the other properties increasing. From the incremental changes in these properties with nitrogen content, for glasses with x= 0, 14, and 28, good linear fits (R2 > 0.99) were obtained, and best-fit slopes are reported here. The property changes and their linearity were consistent with the increased cross-linking of the glass network by tricoordinated nitrogen. The replacement of magnesium by yttrium led to a nonlinear decrease in glass compactness and to nonlinear increases in MV, Tg, and Tds. However, linear correlations were found for MV and ionic volume and for Tg, Tds, and the coordination of (Si,Al)(O,N) tetrahedra of the glass structural units to the modifier cations not involved in charge compensating aluminum ions in fourfold coordination. The replacement of magnesium by yttrium had little effect on Young's modulus, and this result was related to similar changes in the compactness, C. The present results showed that the effects of substituting nitrogen for oxygen and yttrium for magnesium are independent and additive; thus, no synergistic effects of anion and cation substitutions were observed. [source]

Dose-dependent pharmacokinetics of a new Na+/H+ exchanger inhibitor KR-33028 in rats

Young Hoon Kim
Abstract The dose-dependency of the pharmacokinetics of a new Na+/H+ exchanger inhibitor, KR-33028 was evaluated in rats after intravenous and oral administration. After intravenous administration of KR-33028 (1, 5, 10 and 20mg/kg doses), the systemic clearance (Cl) was reduced and AUC was nonlinearly increased as a function of dose. The volume of distribution (Vss), however, remained unchanged as the dose was increased, which was consistent with unaltered plasma protein binding in vitro (unbound fraction = 0.09,0.12). Upon oral administration (2, 10 and 20mg/kg doses), KR-33028 was rapidly absorbed, and this was consistent with high Caco-2 Papp values found in vitro. There were nonlinear increases in AUC and Cmax, and the absolute oral bioavailability (F) was significantly increased as the dose was increased (F = 23.3%, 40.7% and 78.2% for 2, 10 and 20mg/kg doses, respectively). The extent of urinary excretion was low for both intravenous (0.5,0.7%) and oral (0.2,0.8%) doses. The reduced systemic clearance and increased oral bioavailability at high doses appears to be due to a saturable first-pass metabolism. Copyright 2007 John Wiley & Sons, Ltd. [source]