How long does it take a pyrite framboid to form?

Framboids are defined as microscopic, sub-spheroidal clusters of equant and equidimensional microcrystals. The microcrystals are usually constituted of pyrite and framboidal pyrite is one of the most abundant mineral textures in the natural environment. They are of particular interest to geochemists, sedimentologists, paleobiologists and materials scientists because of their potential paleoenvironmental significance, their widespread involvement in fossilization and their potential for the manufacture of self-organizing materials. Here I use a simple diffusion-nucleation model to compute framboid formation times. The results show that pyrite framboids take between 3 h and 3 yr to form depending on framboid size. The time taken for the average sedimentary framboid to form is about 5 days and the average syngenetic framboid forms within 3 days. The shorter formation times for syngenetic compared with diagenetic framboids helps explain the smaller size relative size distributions of syngenetic framboids. This has led to the use of framboid size-frequency measurements as proxies for ancient euxinia. The relatively rapid formation of pyrite framboids explains how pyrite infills and preserves soft tissues before cell lysis and before deformation through burial has been initiated. One unexpected consequence of the model is that it further explains how commonly observed groups of framboids can form contemporaneously

Facilitating Group Work: a Guide to Good Practice

Oakley et al. (2004) and Gibbs (2009) observe that owing to the extensive literature on group work, lecturers searching for a succinct guide on how to facilitate this activity effectively would find it challenging to digest such a large corpus. We extensively reviewed the literature in order to produce a quick and accessible guide for lecturers to use. It is our aspiration that this could be referred to when planning and facilitating group work projects with insights and recommendations informed by our research. Moreover, as this work draws on publications from educators in a wide range of disciplines, we expect this guide to be universally applicable. Recommendations: We recommend that lecturers new to group work should consider implementing the following key steps when carrying out group work: Produce and distribute a Group Work Policy document, Ask students to produce Team Expectations Agreements, Establish a transparent group formation mechanism (e.g. ‘Pair and Share’), Choose assessment methods to align with learning outcomes as related to Person, Process, or Product, Manage emergent conflict and discipline issues using a series of measures of increasing consequence for the student Future work Our group report and artefact could be condensed and edited into a short pamphlet or flyer, which could be distributed to lecturers in different departments as a practical aid for facilitating group projects. In addition, our ‘guide to good practice’ could be further developed in the form of a mobile, or web application for rapid accessibility and convenience

Mental Health Smartphone Apps: Review and Evidence-Based Recommendations for Future Developments

BACKGROUND: The number of mental health apps (MHapps) developed and now available to smartphone users has increased in recent years. MHapps and other technology-based solutions have the potential to play an important part in the future of mental health care; however, there is no single guide for the development of evidence-based MHapps. Many currently available MHapps lack features that would greatly improve their functionality, or include features that are not optimized. Furthermore, MHapp developers rarely conduct or publish trial-based experimental validation of their apps. Indeed, a previous systematic review revealed a complete lack of trial-based evidence for many of the hundreds of MHapps available. OBJECTIVE: To guide future MHapp development, a set of clear, practical, evidence-based recommendations is presented for MHapp developers to create better, more rigorous apps. METHODS: A literature review was conducted, scrutinizing research across diverse fields, including mental health interventions, preventative health, mobile health, and mobile app design. RESULTS: Sixteen recommendations were formulated. Evidence for each recommendation is discussed, and guidance on how these recommendations might be integrated into the overall design of an MHapp is offered. Each recommendation is rated on the basis of the strength of associated evidence. It is important to design an MHapp using a behavioral plan and interactive framework that encourages the user to engage with the app; thus, it may not be possible to incorporate all 16 recommendations into a single MHapp. CONCLUSIONS: Randomized controlled trials are required to validate future MHapps and the principles upon which they are designed, and to further investigate the recommendations presented in this review. Effective MHapps are required to help prevent mental health problems and to ease the burden on health systems

Characterization of health care utilization in patients receiving implantable cardioverter-defibrillator therapies: An analysis of the managed ventricular pacing trial.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) are effective in terminating lethal arrhythmias, but little is known about the degree of health care utilization (HCU) after ICD therapies. OBJECTIVE: Using data from the managed ventricular pacing trial, we sought to identify the incidence and types of HCU in ICD patients after receiving ICD therapy (shocks or antitachycardia pacing [ATP]). METHODS: We analyzed HCU events (ventricular tachyarrhythmia [VTA]-related, heart failure-related, ICD implant procedure-related, ICD system-related, or other) and their association with ICD therapies (shocked ventricular tachycardia episode, ATP-terminated ventricular tachycardia episode, and inappropriately shocked episode). RESULTS: A total of 1879 HCUs occurred in 695 of 1030 subjects (80% primary prevention) and were classified as follows: 133 (7%) VTA-related, 373 (20%) heart failure-related, 97 (5%) implant procedure-related, 115 (6%) system-related, and 1160 (62%) other. Of 2113 treated VTA episodes, 1680 (80%) received ATP only and 433 (20%) received shocks. Stratifying VTA-related HCUs on the basis of the type of ICD therapy delivered, there were 25 HCUs per 100 shocked VTA episodes compared with 1 HCU per 100 ATP-terminated episodes. Inappropriate ICD shocks occurred in 8.7% of the subjects and were associated with 115 HCUs. The majority of HCUs (52%) began in the emergency department, and 66% of all HCUs resulted in hospitalization. CONCLUSION: For VTA-related HCUs, shocks are associated with a 25-fold increase in HCUs compared to VTAs treated by ATP only. Application of evidence-based strategies and automated device-based algorithms to reduce ICD shocks (higher rate cutoffs, use of ATP, and arrhythmia detection) may help reduce HCUs