Search results for "Stability"
showing 10 items of 3085 documents
Students’ accounts of their participation in an intensive long-term learning community
2005
Collaborative learning environments have been analysed extensively, yet we know relatively little about how students experience their participation in long-term learning communities where learners work together over extended periods of time. This study aims to understand pre-service teacher–students’ experiences and accounts of their participation in a university-based long-term learning community. The study investigates issues of change and stability, with respect to the students’ perceptions of participation over the first 2 years of their work within the learning community. The study also addresses the relations between the students’ accounts of participation and their learning experienc…
Synthesis and characterization of vanadyl(IV) complexes of Schiff bases derived from anthranilic acid and salicylaldehyde (or its derivatives) or ace…
1997
Anhydrous, dimeric vanadyl(IV) complexes of Schiff bases derived from [1+1] condensation of salicylaldehyde (or its derivatives) and anthranilic acid, have been synthesized from CH3CN and were characterized by elemental analysis, FTIR, EPR, absorption, TGA, cyclic voltammetry and room temperature magnetic susceptibility measurements. These complexes were found to be oxidized by air in polar solvents like MeOH and DMF to V-V products. The E(1/2) values were found to be around 660 mV indicating that the carboxylate group favours vanadyl(IV) binding when compared to the alkoxo-bound vanadium complexes. Oxidative instability of these complexes are dependent on the substituent on the salicylalde…
Zn(II)-alloferon complexes - Similar sequence, different coordination modes, no antibacterial activity.
2020
Often, in the search for a highly defined scientific phenomenon, a different one becomes apparent. This was also the case of this work, in the scope of which we planned to search for metal-enhanced, novel antibacterial/ antifungal compounds. Instead, we denied the existence of such and revealed the details of the bioinorganic chemistry of Zn(II)-alloferon complexes. Zinc(II) complexes of alloferon 1 and 2, ligands with a sequential difference of one amino acid only, show a substantially different coordination pattern at physiological pH. In the case of Zn(II)-alloferon 1 species, a histamine-like binding mode is observed (N-terminal amine and imidazole of His-1) and the coordination sphere …
Photomagnetic properties of an Iron(II) low-spin complex with an unusually long-lived metastable LIESST state
2007
A comprehensive study of the photomagnetic behavior of the [Fe(L222N5)(CN)2].H2O complex has been carried out. This complex is characterized by a low-spin (LS) iron(II)-metal center up to 400 K and exhibits at 10 K the well-known Light-Induced Excited Spin State Trapping (LIESST) effect. The critical LIESST temperature (T(LIESST)) has been measured to be 105 K. The kinetics of the transition from the metastable high-spin (HS) state to the low-spin state have been determined and used for reproducing the experimental T(LIESST) curve. This study represents a second example of a fully low-spin iron(II)-metal complex up to 400 K, which can be photoexcited at low temperature with an atypical long…
The interplay of emotional instability, empathy, and coping on prosocial and aggressive behaviors
2012
Abstract Mediating and moderating effects of socioemotive traits and coping styles on aggression and prosocial behaviors were examined. A sample of 1557 students from Spain (53% male, M age = 13.12) completed self-report instruments of coping, empathy, emotional instability, physical aggression, and prosocial behaviors. Structural equation analysis showed support for two mediation models but little support for moderation. Emotional instability positively predicted emotion-focused coping, which in turn, positively predicted aggression. In contrast, empathy positively predicted problem-focused coping, which in turn, positively predicted prosocial behaviors. Moreover, problem-focused coping po…
Emociones, estilos de afrontamiento y agresividad en la adolescencia
2012
Este estudio analiza la relación entre las estrategias de afrontamiento y las emociones para determinar en qué medida son procesos relacionados con la conducta agresiva. Se parte del supuesto de que en la agresividad influyen los mecanismos de afrontamiento en la resolución de problemas y el manejo de las emociones: inestabilidad emocional (falta de autocontrol ante situaciones que producen tensión) o empatía (sentimientos orientados al otro que tiene un problema o necesidad). Se ha evaluado una muestra de 1.557 niños y niñas, con un rango de edad entre 12 y 15 años, escolarizados en primer ciclo de Educación Secundaria Obligatoria (ESO) en 36 Centros escolares de la Comunidad Valenciana, s…
Vínculos familiares e inclusión social. Variables predictoras de la conducta prosocial en la infancia
2018
The purpose of this study was to investigate the relationship between prosocial behavior and family environment variables (attachment to the mother and father and abandonment by the mother and father), personal variables (emotional instability, aggression, and coping strategies), and variables that relate to the immediate social environment (peer acceptance and rejection). This study also examined the predictors of prosocial behavior. Prosocial behavior is a personal protective factor that encourages positive relationships between peers and promotes personal and social adjustment behaviors (Mikolajewski, Chavarria, Moltisanti, Hart & Taylor, 2014). A study with a sample of 1,447 chi…
Bridging vs. chelating coordination modes of vinylsilanes in CuI π-Complexes: Structure and stability
2014
Two new copper(I) olefin complexes, [Cu6Cl6(MTrVS)2] (1) and [Cu2Cl2(DMVSP)2] (2), of tridentate bridging methyltrivinylsilane (MTrVS) and bidentate chelating 2-[dimethyl(vinyl)silyl]pyridine (DMVSP) have been synthesized and characterized by single-crystal X-ray structure analysis, IR and 1H NMR spectroscopy. It has been shown that using the alkenylsilanes with required electronic properties, molecular symmetry and conformational flexibility, it is possible to control the formation of optimal copper(I) halide oligomers. The obtained results, together with relevant literature data, also illustrate how the coordination mode of vinylsilanes is related to Cu–(C=C) bond strengthening and, conse…
New delay-dependent stability conditions for time-varying delay systems
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/360924 Open Access This paper addresses the delay-dependent stability for systems with time-varying delay. First, by taking multi-integral terms into consideration, new Lyapunov-Krasovskii functional is defined. Second, in order to reduce the computational complexity of the main results, reciprocally convex approach and some special transformations are introduced, and new delay-dependent stability criteria are proposed, which are less conservative and have less decision variables than some previous results. Finally, two well-known example…
The transient gravitational-wave sky
2013
Interferometric detectors will very soon give us an unprecedented view of the gravitational-wave sky, and in particular of the explosive and transient Universe. Now is the time to challenge our theoretical understanding of short-duration gravitational-wave signatures from cataclysmic events, their connection to more traditional electromagnetic and particle astrophysics, and the data analysis techniques that will make the observations a reality. This paper summarizes the state of the art, future science opportunities, and current challenges in understanding gravitational-wave transients.