Efficacy and cost-effectiveness of a web-based and mobile stress-management intervention for employees: design of a randomized controlled trial

Background: Work-related stress is associated with a variety of mental and emotional problems and can lead to substantial economic costs due to lost productivity, absenteeism or the inability to work. There is a considerable amount of evidence on the effectiveness of traditional face-to-face stress-management interventions for employees; however, they are often costly, time-consuming, and characterized by a high access threshold. Web-based interventions may overcome some of these problems yet the evidence in this field is scarce. This paper describes the protocol for a study that will examine the efficacy and cost-effectiveness of a web-based guided stress-management training which is based on problem solving and emotion regulation and aimed at reducing stress in adult employees. Methods. The study will target stressed employees aged 18 and older. A randomized controlled trial (RCT) design will be applied. Based on a power calculation of d=.35 (1-β of 80%, α =.05), 264 participants will be recruited and randomly assigned to either the intervention group or a six-month waitlist control group. Inclusion criteria include an elevated stress level (Cohen's Perceived Stress Scale-10 ≥ 22) and current employment. Exclusion criteria include risk of suicide or previously diagnosed psychosis or dissociative symptoms. The primary outcome will be perceived stress, and secondary outcomes include depression and anxiety. Data will be collected at baseline and seven weeks and six months after randomization. An extended follow up at 12 months is planned for the intervention group. Moreover, a cost-effectiveness analysis will be conducted from a societal perspective and will include both direct and indirect health care costs. Data will be analyzed on an intention-to-treat basis and per protocol. Discussion. The substantial negative consequences of work-related stress emphasize the necessity for effective stress-management trainings. If the proposed internet intervention proves to be (cost-) effective, a preventative, economical stress-management tool will be conceivable. The strengths and limitations of the present study are discussed. Trial registration. German Register of Clinical Studies (DRKS): DRKS00004749. © 2013 Heber et al.; licensee BioMed Central Ltd

Metamorfe studies van granoliete en verwante hoë-graadse gesteentes in die Suidelike Grenssone van die Limpopo-Metamorfekompleks in Suid-Afrika

D.Sc. (Geology)Please refer to full text to view abstrac

Investigation of soil damping on full-scale test piles

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Conceptual teaching of metamorphic petrology at undergraduate level

Traditionally, undergraduate metamorphic petrology focuses on topics including classification of metamorphic rocks, texture and fabric of metamorphic rocks, and the variation of mineral assemblages as a function of temperature, pressure and rock composition (see, for example, the table of contents in the 2001 textbook by John Winter). Consequently, metamorphic geology can easily become a relatively boring fact-memorising subject. Obviously, factual knowledge is important but, as we will show in this presentation, putting them in context related to concepts/themes (Figure 1) will make the learning experience more efficient and in particular more fun for both the student and the lecturer. Metamorphic geology at James Cook University is taught in two undergraduate subjects of six weeks each. Both subjects have “Understanding crustal evolution using pressure-temperature paths” as the main theme (e.g., Spear, 1995). Each subject includes two 50-minute lecture periods and one three-hour practical session per week. The introductory metamorphic geology subject introduces the basic concepts: controlling factors (pressure, temperature, fluid), geotherms and pressure-temperature paths, mineral assemblages and metamorphic reactions (Figure 1). The concepts are explained in lectures and during the practicals using examples and exercises. Specific teaching material was written for both subjects, which is updated every year using feedback from the students. The advanced metamorphic geology subject is entirely structured around a practical case study in which the students have the task to reconstruct the uplift history of a granulite-facies metamorphic terrain. The methods used in this practical are largely based on the concepts already introduced in the introductory metamorphic geology subject. The practical includes petrography (identification of mineral reactions), construction of Thompson AFM diagrams and Fe-Mg KD diagrams, calculation of pressure and temperature conditions and retrograde pressure-temperature paths. The results are presented in an article-format report. The feedback from students to this approach has generally been positive. In particular the complete integration of lectures and the case study has been well received by the students

Fluid-rock interaction in retrograde granulites of the Southern Marginal Zone, Limpopo high grade terrain, South Africa

AbstractFluid infiltration into retrograde granulites of the Southern Marginal Zone (Limpopo high grade terrain) is exemplified by hydration reactions, shear zone hosted metasomatism, and lode gold mineralisation. Hydration reactions include the breakdown of cordierite and orthopyroxene to gedrite + kyanite, and anthophyllite, respectively. Metamorphic petrology, fluid inclusions, and field data indicate that a low H2O-activity carbon-saturated CO2-rich and a saline aqueous fluid infiltrated the Southern Marginal Zone during exhumation. The formation of anthophyllite after orthopyroxene established a regional retrograde anthophyllite-in isograd and occurred at P-T conditions of ∼6 kbar and 610 °C, which fixes the minimum mole fraction of H2O in the CO2-rich fluid phase at ∼0.1. The maximum H2O mole fraction is fixed by the lower temperature limit (∼800 °C) for partial melting at ∼0.3. C-O-H fluid calculations show that the CO2-rich fluid had an oxygen fugacity that was 0.6 log10 units higher than that of the fayalite-magnetite-quartz buffer and that the CO2/(CO2+CH4) mole ratio of this fluid was 1. The presence of dominantly relatively low density CO2-rich fluid inclusions in the hydrated granulites indicates that the fluid pressure was less than the lithostatic pressure. This can be explained by strike slip faulting and/or an increase of the rock permeability caused by hydration reactions

ORTHOPYROXENE plus SILLIMANITE PREDATING SAPPHIRINE plus QUARTZ: A RARE CASE OF ULTRAHIGH-TEMPERATURE METAMORPHISM FROM THE CENTRAL ZONE, LIMPOPO COMPLEX, SOUTH AFRICA

Sapphirine + quartz and orthopyroxene + sillimanite occur in garnet from an Mg-Al granulite from the Central Zone of the Limpopo Complex in South Africa. Textural evidence and a chemical gradient in garnet between the zones preserving the inclusions argue for the formation of sapphirine + quartz after orthopyroxene + sillimanite. Petrological observations, pressure-temperature phase diagrams, and compositional and model proportion results on isopleths indicate the sapphirine + quartz + garnet + orthopyroxene (high-Al) assemblage as the peak metamorphic assemblage (similar to 1050 degrees C at similar to 8.5 kbars), whereas orthopyroxene (low-Al) + sillimanite represents the prograde stage (at ca. 900 degrees C at similar to 8.5 kbars). Our report of these two diagnostic ultrahigh-temperature mineral assemblages in garnet from an Mg-Al granulite is unique, given the rare occurrence of sapphirine + quartz postdating orthopyroxene + sillimanite assemblage in granulites

Explaining the effects of processing on the electrical properties of PEDOT:PSS.

By simultaneously measuring the Seebeck coefficient and the conductivity in differently processed PEDOT:PSS films, fundamental understanding is gained on how commonly used processing methods improve the conductivity of PEDOT:PSS. Use of a high boiling solvent (HBS) enhances the conductivity by 3 orders of magnitude, as is well-known. Simultaneously, the Seebeck coefficient S remains largely unaffected, which is shown to imply that the conductivity is improved by enhanced connectivity between PEDOT-rich filaments within the film, rather than by improved conductivity of the separate PEDOT filaments. Post-treatment of PEDOT:PSS films by washing with H2SO4 leads to a similarly enhanced conductivity and a significant reduction in the layer thickness. This reduction strikingly corresponds to the initial PSS ratio in the PEDOT:PSS films, which suggests removal and replacement of PSS in PEDOT:PSS by HSO4- or SO42- after washing. Like for the HBS treatment, this improves the connectivity between PEDOT filaments. Depending on whether the H2SO4 treatment is or is not preceded by an HBS treatment also the intra-filament transport is affected. We show that by characterization of S and s it is possible to obtain more fundamental understanding of the effects of processing on the (thermo)electrical characteristics of PEDOT:PSS