Effect of Jitter on the Settling Time of Mesochronous Clock Retiming Circuits

It is well known that timing jitter can degrade the bit error rate (BER) of receivers that recover the clock from input data. However, timing jitter can also result in an indefinite increase in the settling time of clock recovery circuits, particularly in low swing mesochronous systems. Mesochronous clock retiming circuits are required in repeaterless low swing on-chip interconnects. We first discuss how timing jitter can result in a large increase in the settling time of the clock recovery circuit. Next, the circuit is modelled as a Markov chain with absorbing states. The mean time to absorption of the Markov chain, which represents the mean settling time of the circuit, is determined. The model is validated through behavioural simulations of the circuit, the results of which match well with the model predictions. We consider circuits with (i) data dependent jitter, (ii) random jitter, and (iii) combination of both of them. We show that a mismatch between the strengths of up and down corrections of the retiming can reduce the settling time. In particular, a 10% mismatch can reduce the mean settling time by up to 40%. We leverage this fact toward improving the settling time performance, and propose useful techniques based on biased training sequences and mismatched charge pumps. We also present a coarse+fine clock retiming circuit, which can operate in coarse first mode, to reduce the settling time substantially. These fast settling retiming circuits are verified with circuit simulations.Comment: 23 pages, 40 figure

Religious faith and mental health outcomes

In this chapter we review recent research regarding the relationship between religious faith/spirituality and mental health outcomes, as well as provide directions for future research and discussion. The specific aspects of mental health and illness that we focus on include well-being, depression, anxiety, substance abuse, and schizophrenia. We also briefly discuss research pertaining to religious faith and personality disorders, eating disorders, somatoform disorders, and bipolar disorder

Plant Metabolomics: An Emerging Technology for Crop Improvement

The astounding ability of plants to make smart decisions in response to environment is evident. As they have evolved a long list of complex and unique processes that involve photosynthesis, totipotency, long-distance signaling, and ability to restore structural and metabolic memory, recognition, and communication via emission of the selected class of volatiles. In recent years, use of metabolite profiling techniques in detection, unambiguous identification, quantification, and rapid analysis of the minute quantity of cellular micromolecules has increased considerably. Metabolomics is key to understand the chemical footprints during different phases of growth and development of plants. To feed the ever-increasing population with limited inputs and in a rapidly changing environment is the biggest challenges that the world agriculture faces today. To achieve the project genetic gains, the breeding strategies employing marker-assisted selection for high-yielding varieties and identifying germplasm resistant to abiotic and biotic stresses are already in vogue. Henceforth, new approaches are needed to discover and deploy agronomically important gene/s that can help crops better withstand weather extremes and growing pest prevalence worldwide. In this context, metabolic engineering technology looks viable option, with immense potential to deliver the future crops

Correlates of contraceptive use among couples in slums of Chandigarh, India

Background: Population explosion in developing countries is the major problem which neutralizes all the gains and developments achieved in the country. In India, in spite of availability of many contraceptive techniques, the couple protection rate continues to be inadequate. The objective of the study was to compare the fertility behavior of men and women in terms of awareness, preferred and intended use of contraceptives.Methods: Community-based longitudinal study was conducted among 667 couples in four randomly selected slum areas of Chandigarh using a two-stage systematic sample design. Data was collected using a predesigned and pretested semi-structured interview schedule conducting house-to-house survey. Impact of interventions in the form of health education was assessed at the end of follow-up.Results: There were 193 (28.9%) female respondents married before attaining 18 years of age. Medium ages at marriage for women were found to be 18 years. Majority, 91 (13.6%) women delivered first baby prior to 18 years of age. Age wise contraceptive prevalence rate was found to be maximum (66.2%) among women aged 36-49 years. Contraceptive use was more common in case of nuclear families (60.4%) and in case of improvident maternity (65.3%). Overall awareness of contraceptives among couples was found to be among 545 (81.7%) couples whereas, only 382 (57.3) were using contraceptives currently.Conclusions: Migratory couples, having at least one female child, and with history of still births were more likely to use contraceptives. Interventions in the form of health education have some positive role in increasing contraceptive awareness and current as well as intended uses of contraception

Recovering Shared Objects Without Stable Storage

This paper considers the problem of building fault-tolerant shared objects when processes can crash and recover but lose their persistent state on recovery. This Diskless Crash-Recovery (DCR) model matches the way many long-lived systems are built. We show that it presents new challenges, as operations that are recorded at a quorum may not persist after some of the processes in that quorum crash and then recover. To address this problem, we introduce the notion of crash-consistent quorums, where no recoveries happen during the quorum responses. We show that relying on crash-consistent quorums enables a recovery procedure that can recover all operations that successfully finished. Crash-consistent quorums can be easily identified using a mechanism we term the crash vector, which tracks the causal relationship between crashes, recoveries, and other operations. We apply crash-consistent quorums and crash vectors to build two storage primitives. We give a new algorithm for multi-writer, multi-reader atomic registers in the DCR model that guarantees safety under all conditions and termination under a natural condition. It improves on the best prior protocol for this problem by requiring fewer rounds, fewer nodes to participate in the quorum, and a less restrictive liveness condition. We also present a more efficient single-writer, single-reader atomic set - a virtual stable storage abstraction. It can be used to lift any existing algorithm from the traditional Crash-Recovery model to the DCR model. We examine a specific application, state machine replication, and show that existing diskless protocols can violate their correctness guarantees, while ours offers a general and correct solution