We present a simple, efficient, and unified solution to the problems of synchronizing, initializing, and integrating clocks for systems with different types of failures: crash, omission, and arbitrary failures with and without message authentication. This is the first known solution that achieves optimal accuracy—the accuracy of synchronized clocks (with respect to real time) is as good as that specified for the underlying hardware clocks. The solution is also optimal with respect to the number of faulty processes that can be tolerated to achieve this accuracy.

We describe a Byzantine Agreement algorithm, with early stopping, for systems with arbitrary process failures. The algorithm presented is simpler and more efficient than those previously known. It was derived using a broadcast primitive that provides properties of message authentication and thus restricts the disruptive behavior of faulty processes. This primitive is a general tool for deriving fault-tolerant algorithms in the presence of arbitrary failures.

There is a dearth of published research on uptake and utility of mental health apps in India, despite a rising global trend in the application of technology in the field of mental health. We describe the development and pilot testing of a self-help intervention for depression, PUSH-D (Practice and Use Self-Help for Depression) for urban Indians. This guided self-help app, with essential and optional zone sections, was developed to provide a comprehensive coverage of therapeutic strategies drawn from cognitive behavior therapy, interpersonal therapy, supportive psychotherapy, and positive psychology. Pilot testing was carried out using a single group pre-, post- and follow-up design in 78 eligible participants. Participants were typically young adults with major depression or dysthymia and significant impairment in functioning. Almost two-thirds of the participants had never sought professional mental health help. Significant reductions in depression and improvement in the functioning and well-being were notedon standardized measures in participants completing all 10 essential zone sections. These gains were maintained at follow-up. The results were similar for partial completers, who completed fiveout of the 10 essential sections. PUSH-D is one of the first indigenously developed self-help apps for depression and it shows promise in reducing the treatment gap for depression in India.