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The hydration of Na-saturated Wyoming-type montmorillonite is investigated by Monte Carlo simulations at constant stress in the NP[sub zz]T ensemble and at constant chemical potential in the μVT ensemble, at the sedimentary basin temperature of 353 K and pressure of 625 bar, equivalent to 2–4 km depth. The simulations use procedures established in Chávez-Páez et al. [J. Chem. Phys. 114, 1405 (2001)]. At these conditions, simulations predict a single stable form of 1,2-water layer Na–montmorillonite, containing 164.38 mg/g or 53.37 molecules/layer of adsorbed water and having a spacing of 12.72 Å. The corresponding density is 0.32 g/ml. Sodium ions are coordinated with six molecules of water separated 2.30–2.33 Å. Water molecules are closer to the central interlayer plane and the spacing is larger than that at 300 K and 1 bar. The interlayer configuration consists of two symmetrical layers of oriented water molecules 1.038 Å from the central plane, with the hydrogen atoms in two outermost layers, 3.826 Å apart, and the sodium ions on the central plane located between the water layers. The interlayer configuration can be considered to be a stable two-layer intermediate between the one- and two-layer hydrates. Our simulations do not predict formation of other hydrates of Na–montmorillonite at 353 K and 615 bar. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

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The adsorption of barium by Ca-exchanged clinoptilolite and montmorillonite is presented. The kinetics of adsorption of Ba(2+) were evaluated contacting 1g portion of each adsorber with 100mL 0.1N BaCl(2) for 200 h. Adsorption by Ca-clinoptilolite is defined by second-order kinetics of rate constant K(v) 8.232 x 10(-2) g mg(-1)h(-1) and maximum removal of 71.885 mg g(-1). It is a two-stage process initiated by a rapid uptake of Ba(2+) followed by more moderate kinetics. The adsorption isotherms were determined contacting 0.2g of each adsorber with 10 mL 0.1-0.005N BaCl(2)+CaCl(2) solution, Ba(2+)/Ca(2+) ratio 1, for periods of 7 days for the tuff and 2 days for the clay. The equilibrium adsorption is described by the Langmuir model, of equilibrium constant K 0.0151 L mg(-1) and maximum adsorption of 15.29 mg g(-1). The adsorption of Ba(2+) by Ca-exchanged montmorillonite also follows a second-order reaction of rate constant K(v) 3.179 x 10(-2) g mg(-1)h(-1), and calculated separation of 36.74 mg g(-1); the Langmuir isotherm is defined by the constant K 0.034 L mg(-1) and maximum adsorption of 15.29 mg g(-1). X-ray diffraction shows that the exchange of Ba(2+) modifies the d(001) of Ca-montmorillonite from 15.4 to 12.4A., ((c) 2009 Elsevier B.V. All rights reserved.)

Factors that influence the prognosis for recovery in psychosocial risk families: The role of child resilience. This study analyses the indicators, such as child resilience, that influence prognosis for recovery in psychosocial risk families, by examining the combination that better discriminates between a favourable prognosis and an unfavourable one. For this purpose, the evaluation of the prognosis of 418 cases of children and their families (224 two-parents and 194 one-parent) were examined through the Psychosocial Risk Profile of the Family, which was filled in by professionals from social services. The impact level on development, the temporality of the problem, and parents' attitudes about the intervention, their children and the service affected the prognosis of both families. Child resilience selectively influenced the favourable prognosis in two-parent families whereas the risk level affected the unfavourable prognosis in one-parent families. Child resilience was only related to those risk indicators which reflect more continuity of the problem and an accumulation of negative life events, but also to some compensatory factors such as the parents' expectations of the child's future that reflect parental competence.

In accordance with the fact the aging process is closely related to the individual nutrition, it is possible to infer that the daily diet could help and improve, to a certain degree, to the elderly well-being. Based on this and making use of the food technology expertise, the development of a low cost, easily prepared and preserved product, in accordance with the taste and needs of the elderly people was considered. The objective of this project was to elaborate an intermediate moisture food (IMF) based on texturized soy protein with carrots, potatoes and peas, adding humectants and microstatic agents according to the moist and dry infusion methods. Fried bacon was added to some formulas in order to evaluate the sensorial preference of the product with and without bacon by elderly people and effect of the bacon on the water activity (aw) reduction. The aw for the product with added bacon was 0.859 and 0.896 for the one with no added bacon. The product with added bacon allowed 20% of the nutritional requirements of the elderly people of protein, vitamin A and thiamine. Both formulas were equally highly accepted by the elderly people (80%) and were microbiologically stable for 8 weeks period at 25 degrees C and 55% RH in aluminium/cellophane/polyethylene and polyester/polyethylene flexible packages. We can conclude that IMF may be an alternative to improve the diet of the elderly people.