Juan Francisco Díaz Morales

A Global Look at Time: A 24-Country Study of the Equivalence of the Zimbardo Time Perspective Inventory

In this article, we assess the structural equivalence of the Zimbardo Time Perspective Inventory (ZTPI) across 26 samples from 24 countries (N = 12,200). The ZTPI is proven to be a valid and reliable index of individual differences in time perspective across five temporal categories: Past Negative, Past Positive, Present Fatalistic, Present Hedonistic, and Future. We obtained evidence for invariance of 36 items (out of 56) and also the five-factor structure of ZTPI across 23 countries. The short ZTPI scales are reliable for country-level analysis, whereas we recommend the use of the full scales for individual-level analysis. The short version of ZTPI will further promote integration of research in the time perspective domain in relation to many different psycho-social processes.

Composite and preferences Scales of Morningness: reliability and factor invariance in adult and university samples.

The creation and adaptation of scales or inventories assessing specific circadian typologies has been a predominant focus within the field of chronopsychology. The present study addressed the psychometric properties of two scales of morningness-eveningness: the Morningness Composite Scale (CS; Smith, Reilly, & Midkiff, 1989) and the Early/Late Preferences Scale (PS; Smith, Folkard, Schmieder, Parra, Spelten, & Almirall, 1993). Internal consistency and factor invariance of the CS and PS were analyzed in two samples: a group of 203 university students (age range = 19-30) and a group of 125 working adults (age range = 31-65). Results indicated satisfactory internal consistency for both full scales with each age group and confirmed the factor invariance across age for the two CS factors and one of the PS factors. A higher tendency in morningness on both scales was noted in the adult sample.

A nanoscopic approach to the kinetics of anhydrite (100) surface growth in the range of temperatures between 60 and 120 °C

Abstract In situ observations of the growth of the anhydrite (100) surface in contact with supersaturated aqueous solutions under conditions within the stability field of this mineral (60-120 °C) were conducted using a hydrothermal atomic force microscope (HAFM). Advancement rates were measured for [001] steps, the most stable ones on the anhydrite (100) surface. Isothermal data fit well to linear correlations between step advancement rate and supersaturation; the activation energy for step advancement is 73 ± 5 kJ/mol. This is not significantly higher than activation energies reported for the growth of gypsum (60-70 kJ/mol) and does not support that slow dehydration rates of aqueous calcium is responsible for the well-known difficulty to precipitate anhydrite crystals from supersaturated aqueous solutions at temperatures well above the anhydrite-gypsum equilibrium temperature. The role of structural factors that could inhibit the growth of anhydrite is discussed.

Nanoscopic characteristics of anhydrite (100) surface growth under mild hydrothermal conditions

Anhydrite (CaSO4) is a major component of evaporitic rocks and is currently forming in submarine hydrothermal fields, where its dissolution and precipitation plays a significant role in controlling porosity. Anhydrite also is a component of undesirable scale on heat transfer surfaces during desalinization and waste water treatments. Knowledge of the molecular processes that control anhydrite growth and dissolution is crucial to understand the geochemical cycling of elements in some natural systems and to develop strategies to limit scale formation on hot surfaces in numerous industrial processes. Several works investigated the nanoscale characteristics of anhydrite growth and dissolution at 25oC [1,2]. However, primary anhydrite mainly forms at temperatures above 60oC. In this work we study the growth of anhydrite (100) surface in contact with supersaturated aqueous solutions (βanhydrite = 1-3.6) under mild hydrothermal conditions (T = 50-115oC, P = 1 atm). The experiments were performed using a hydrothermal atomic force microscope (HAFM) [3]. Our observations showed that: (i) anhydrite (100) surface grows by lateral spreading of monomolecular layers (3.5 Å in height), which originate at cleavage steps, (ii) the growth is highly anisotropic, with very significant differences in advance speed along different directions (S[001] (or S[00-1]) >> S[011] > S[010]), (iii) growth anisotropy is especially evident for <001>, with [001] and [00-1] alternating as fast and slow directions in successive monolayers, (iv) these growth characteristics determine that fast-moving steps combine with slow-moving steps to form bilayer steps around screw dislocations, (v) a reduced number of two-dimensional nuclei (≤ 1nuclei/μm2) forms at T ≥ 80oC and βanhydrite ≥ 2, (vi) two-dimensional nuclei also are monomolecular and their pseudo-triangular shape also reflects the growth anisotropy. Most of anhydrite (100) surface growth characteristics at mild hydrothermal conditions coincide with those reported for its growth at 25oC [2], which evidences that the strong structural control observed at room temperature extends into higher temperature conditions. The marked growth anisotropy results from the non-equivalent geometry of [010] and [0-10] steps in the monolayer. The existence of two-fold screw axes along [100] explains the alternation of [001] and [00-1] as fast-moving and slow-moving directions in successive monolayers. Highly anisotropic growth at the nanoscale seems to be a feature common to crystal surfaces perpendicular to two-fold screw axes. Acknowledgements: We thank Guntram Jordan for kindly providing access to the Hydrothermal Atomic Force Microscope and training J.M. in using it. We thank Spanish Ministerio de Ciencia e Innovación (CGL2007-65523-C02-01 and CGL2010-20134-C02-01) for financial support.