The zone of saturation plays significant roles in decisions regarding soil classification systems and land use both present and potential. This study was conducted to determine the status of water tables, morphological features, and groundwater hydrology and to evaluate the zone of saturation on selected soils (Aquolls and Hapludolls) of a Mollisol catena. Water table depths and the amount of precipitation were measured for a 10‐year period on five soils formed in glacial till or till‐derived sediments in central Iowa. Results show that the depth of the water table, duration of saturation, morphological features, and recharge and discharge to groundwater varied with geomorphic position in the Mollisol catena. In general, soils on summit and shoulder positions (Hapludolls) are not saturated and have high chromas without redoximorphic features in the B horizon, have deeper water tables, and have maximum fluctuation of water table levels. The soils on toeslopes and depressions (Aquolls) have the shallowest water tables, have the longest time of saturation, and have B horizons with gray matrices, bright mottles, and Fe‐Mn concretions. Nicollet soils (fine‐loamy, mixed, mesic Aquic Hapludoll) on backslope positions have intermediate characteristics. Redoximorphic features present in these soils are correlated with the fluctuating depth of the present‐day water table. The extent of recharge and discharge and artificial the drainage are contributing factors to the water table level. Data for water table level and calcite/dolomite ratio indicate that ephemeral recharge and discharge of groundwater occur in the soils on lower landscape positions. Recharge is the dominant process in the soils of higher landscape. This study was designed to contribute to the understanding of drainage class‐water table‐morphological features of soils in this region. The apparent drainage conditions and the redoximorphic features contribute to the testing and clarification of soil classification and soil taxonomy.
Biomolecular folding often occurs through a cooperative two-state reactant ↔ product transition; the term cooperative does not convey that intermediate structures are nonexistent but rather that these states are not observable by existing experimental techniques. Because of this, few intermediates have been studied and characterized. Recently, ion mobility spectrometry (IMS) measurements revealed that the oligomer polyproline-13 (Pro13, which in propanol (PrOH) favors the right-handed helical PPI structure having adjacent pyrrolidine rings in a cis configuration) folds through six sequential long-lived intermediates as it converts to the all-trans-configured PPII structure that is favored in aqueous solutions. Here, we examine the PPI → PPII folding transition for a HisPro13 sequence, i.e., Pro13 having a single histidine residue added to the N-terminus. Remarkably, the IMS measurements show that, upon addition of histidine, all of the IMS peaks associated with intermediate structures disappear. Instead, HisPro13 folds via a cooperative two-state transition, delayed by a significant induction period. The induction period is temperature dependent-shifting the transition to longer times at lower temperatures. Equilibrium studies show that the HisPro13 PPI → PPII transition is endothermic but favored entropically. From these clues, we propose a sequential folding mechanism and develop a model that suggests that ∼13-17 long-lived intermediates are likely responsible for the induction period. In this model, intermediates are separated by average individual activation barriers of ∼90 kJ·mol, and are entropically favorable.
In this paper, we introduce a class of P -η-accretive mappings, an extension of η-m-accretive mappings [C.E. Chidume, K.R. Kazmi, H. Zegeye, Iterative approximation of a solution of a general variationallike inclusion in Banach spaces, Int. J. Math. Math. Sci. 22 (2004) 1159-1168] and P -accretive mappings [Y.-P. Fang, N.-J. Huang, H -accretive operators and resolvent operator technique for solving variational inclusions in Banach spaces, Appl. Math. Lett. 17 (2004) 647-653], in real Banach spaces. We prove some properties of P -η-accretive mappings and give the notion of proximal-point mapping, termed as P -η-proximal-point mapping, associated with P -η-accretive mapping. Further, using P -η-proximal-point mapping technique, we prove the existence of solution and discuss the convergence analysis of iterative algorithm, for multi-valued variational-like inclusions in real Banach space. The theorems presented in this paper extend and improve many known results in the literature.
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